On 8/31/2011 2:33 PM, NT wrote:
On Aug 31, 7:11 pm, John wrote:
On 8/31/2011 1:06 PM, The Ghost In The Machine wrote:



YES A-NT-MAN BUT THE RMS REFERS TO THE AC WAVEFORM NOT THE DC OUTPUT.
HENCE THERE IS NO SUCH THING AS RMS DC VOLTAGE.
PATECUM
TGITM

Root Mean Square does not imply an ac waveform, its jsut most commonly
used for ac waveforms. Every stable waveform has an rms value, even
perfect dc.


Actually, RMS DC voltage is a redundant expression since DC is RMS.

I realised it was perhaps not the best phrasing. But... would the dc
component be the average V or the rms?


NT

DC is all of the following: Average, Peak, RMS, Mean, Mode, and most
anything else.

John S

Generally, in electronics, "DC component" is defined as the average
value (say, over a period of a periodic waveform). So a 1V peak sine
wave sitting on top of 1VDC would have DC component of 1.0V.
A 1V peak sine wave has a DC component of 0.

The RMS value is the heating value- a 1 ohm resistor with 1VDC across
it will dissipate 1W. A 1 ohm resistor with 1.414V peak sine wave
across it (1 V RMS) will dissipate 1W.

A 1 ohm resistor powered with a 1V peak sine wave sitting on top of
1VDC will dissipate a bit more than 1 watt (RMS value is sqrt(3/2) if
you want to get analytical about it, so about 1.22W).

Thank you SP. Amid all the chest-pounding and playground antics here I can
actually learn something.

"NT" wrote in message
...

On Aug 31, 1:36 am, John Fields wrote:
On Tue, 30 Aug 2011 05:11:20 -0700 (PDT), NT
wrote:
On Aug 30, 12:39 pm, John Fields
wrote:
On Mon, 29 Aug 2011 07:25:23 -0700 (PDT), NT
wrote:

IME relays pull in at in the region of half rated voltage, and dc
ratings are typically about half the voltage of the ac rating, which
gives an idea of how much current is determined by L and how much by
R.

---
IME, most relays (with either AC or DC coils) are guaranteed to pull
in at about 80% of their rated coil voltage, so I'm at a loss trying
to understand what you meant by: "dc ratings are typically about half
of the ac rating."

Can you elaborate, please?

When relays have dual ratings for ac and dc, its normal for the dc
voltage rating to be half the ac voltage rating.

Running your relay on 220v 60Hz it will work fine.

Knowing nothing about the contactor, other than that it's specified to
energize when 240V 50Hz is placed across the coil, your imprimatur is
premature.

I really dont agree. I do know the basics about relays, and one
normally finds that pull-in occurs at around 50% rated voltage. The OP
is welcome to test theirs to see if it behaves the usual way.

Contact closing speed will be slightly slower. Margin will be reduced,
but its only being reduced from enormous to slightly less enormous,
so its a non-issue except in very unusual situations.

It seems you've forgotten that when the armature makes, and the
magnetic circuit is closed, the inductance of the coil will rise.

I dont know why you think I've forgotten it. What's relevant here is
inductance in the closed position.

I disagree.

Since the relay is open when power is applied to the coil, it's the
open inductance (and the resistance, of course) which will determine
how much current will flow through the coil, that current being what
generates the magnetic field to start the armature on its way.

yup

Then when the relay closes, the closed inductance comes into play and
holds the armature in place until the current through the coil is
reduced to a point where the armature's return spring overcomes the
weakened magnetic field, allowing the armature to open.

yes. I guess in theory both matter, one determines closing behaviour,
the other ensures the relay doesnt overheat. In practice though the
margins are very large, and its normal to simply fix holding current
to suit the relay, and not worry about closing current, which will be
so close as to make no real world difference in all but exceptional
circumstances. But yes, we can consider both if need be.


Such being the case, the current in it will diminish,

true with all relays under all ac conditions. Theyre designed to work
that way.

reducing the
hold on the armature and making the contacts more likely to chatter.

No, its exactly how theyre designed to operate.

The vibration tolerance of
the contacts will be little affected in practice; if your environment
is harsh enough to shake the relay contact open, then you've got
bigger worries than contacts crackling.
If instead you meant you would use it on 110v 60Hz, then dont. But you
could use diodes to get a higher dc voltage and use that.

Interesting conjecture.

Where's the conjecture? I get the feeling you could do with bringing
your skills up to speed on relays.

---
Perhaps.
---

Something like this?

+-----+
120AC--|~ +|----+
| | |
| | [COIL]
| | |
120AC--|~ -|----+
+-----+

That would work.

Not in all cases, certainly.

I'd like to see you find one single electromechanical relay that wont
work for.


Since the coil has an impedance of about 6600 ohms at 50Hz, then the
current through it will be:

E 240V
I = --- = ------- = 0.036A = 36mA
Z 6600R

Then, since the coil has a resistance of 4800 ohms, the DC voltage
across it required to force 36mA through it would be:

E = IR = 0.036A * 4800R ~ 174V.

You're not saying where you got those figures from.

---
The P&B MR5A I talked about in an earlier post, which has a 240V
50/60Hz coil, a coil resistance of 4800 ohms, an impedance of ~ 6600
ohms at 50 Hz, an open inductance of 14.5 henrys, and a closed
inductance of 16 henrys

Typically dc rating is half ac rating.

But I don't think "typical" is what we're after since we want
something that will _always_ work.

This 2:1 ratio normally is good for relays, and the OP can check his
to see if it conforms to that. If it does, the thing will always work
when subject to this formula.

FWIW, when ac is applied you get puling force plus vibration. With dc
there is no vibration component when its closed, so less holding
current is needed. How much less I've really no idea.

Some relays are fast movers capable of 100s of Hz, some are slow. Ac
relays can always work on dc, but dc ones often dont work ok on ac.


Since current is what's doing the work, my real-world example shows
that 240V 50 Hz RMS impressed across a load with an impedance of 6600
ohms will force 36mA RMS of current through the load.

Then, since it's current that's doing the work, 36mA of DC through the
coil should accomplish the same thing.
---

The peak voltage out of the bridge would be:

E = RMS * sqrt(2) = 120 * 1.414 ~ 170V.

Pretty close, but at 120Hz, the reactance of the coil would increase,
limiting the current to something less than the 36mA needed to close
the armature.

The effect of the relay's inductance, when run off a BR, is simply to
smooth the current flow somewhat.

---
Yeah, I know, said so earlier, and posted a simulation showing the
ripple.
---

Mean current remains much the same.
So we're looking for 120v rms, which is what the BR would deliver.

---
But, what it won't deliver is the worst-case voltage required over the
interval required to guarantee the armature will close.

Re ripple: If the relay is designed to run on ac 50 or 60Hz, its
designed and rated to live with the current and force variations that
go along with that, 100-120 times a second. Running it on rectified
mains will only serve to reduce the current variations through the
cycle, it wont cause the relay any issues.

Re rms voltage: With my 2:1 figures, rectified 120v is spot on. With
your 174v figure, 120v is well within the 50% margin. Of course for
some uses that margin would need to be confirmed by testing before
production, and reconfirmed if a new relay type is used. Or as you
say, a cap could be added. Or for off brand consumer goods, in it
goes, relays are good for it.


However, the reactance of the coil will smooth the current and the
addition of a capacitor in parallel with the coil will remove some of
the ripple and allow the coil to see more nearly pure DC.

and overheat the relay by increasing its rms dc voltage to above 120v.

There's no such thing as "rms dc voltage",

RMS can be applied to any and every waveform, dc included. Its very
relevant when working with rectified ac, semismoothed or unsmoothed.

and if the relay is
designed to operate on AC with a certain RMS current in its coil, how
can it possibly overheat if that current is DC?

With the same current it wont, with higher curren ti will. IIRC you
proposed using 174v rms, that would be ok on your specific relay, but
not a universal solution.

NT
-----------------------
I sense a bit of cross confusion in this thread.

a)Do not the AC/DC ratings refer to the contact rating rather than the coil
rating? As with any switch, there is a big derating of contacts designed for
AC use but applied to DC- Example a typical 120V 15 A light switch would
fail at 15A 120V DC- it might work at 15A, 12V. Older switches with good
snap contacts do much better.

You indicate experience for the factor of 2:1- but is this something that
translates across the AC/DC barrier?

b) John indicates 174VDC giving 0.036A would be OK- for closing. However
when closed, the holding current will be 0.031A and this is the steady state
current that is involved in heating when the relay is closed. For DC the
voltage would need to be about 150VDC [ (174*0.031/0.036)^2]. So it
remains to be seen if that is sufficient to close the relay. According to
you- it would be more than adequate. From John's 80% criterion it is
inadequate.- so point (c).

c) The peak force is related to the square of peak flux For AC, this is
proportional to (Vrms/f)^2 independent of the magnetic medium. The magnetic
medium determines the corresponding peak current. While a DC current of
0.036A corresponds to an rms current of the same magnitude, and the average
force is the same, at that current, as the average force in the AC case, it
is well below the peak force (about a factor of 2, ). This may have have a
bearing on the relay's operation- just a conjecture.


Don Kelly
cross out to reply







WINDOW 3 32 32 VTop 0
SYMATTR InstName C1
SYMATTR Value 10µ
TEXT -298 246 Left 0 !.tran .05

If the relay is spec'ed as "must make" at 80% of rated current through
the coil (~29mA), then note that with a 10µF cap in parallel with the
coil the relay will _always_ make using full-wave rectified 120V 60Hz
mains.

--
JF

John S wrote:

On 8/31/2011 1:06 PM, The Ghost In The Machine wrote:

YES A-NT-MAN BUT THE RMS REFERS TO THE AC WAVEFORM NOT THE DC OUTPUT.
HENCE THERE IS NO SUCH THING AS RMS DC VOLTAGE.
PATECUM
TGITM

Actually, RMS DC voltage is a redundant expression since DC is RMS.


RMS = 'Roy? Mouthy & Stupid.'


--
You can't have a sense of humor, if you have no sense.

In article , John S
wrote:

On 8/31/2011 2:33 PM, NT wrote:
On Aug 31, 7:11 pm, John wrote:
On 8/31/2011 1:06 PM, The Ghost In The Machine wrote:



YES A-NT-MAN BUT THE RMS REFERS TO THE AC WAVEFORM NOT THE DC OUTPUT.
HENCE THERE IS NO SUCH THING AS RMS DC VOLTAGE.
PATECUM
TGITM

Root Mean Square does not imply an ac waveform, its jsut most commonly
used for ac waveforms. Every stable waveform has an rms value, even
perfect dc.


Actually, RMS DC voltage is a redundant expression since DC is RMS.

I realised it was perhaps not the best phrasing. But... would the dc
component be the average V or the rms?


NT

DC is all of the following: Average, Peak, RMS, Mean, Mode, and most
anything else.

John S

but not peak to peak...

On Sep 1, 5:54*am, "Don Kelly" wrote:
"NT" *wrote in message
...
On Aug 31, 1:36 am, John Fields wrote:
On Tue, 30 Aug 2011 05:11:20 -0700 (PDT), NT
wrote:
On Aug 30, 12:39 pm, John Fields
wrote:
On Mon, 29 Aug 2011 07:25:23 -0700 (PDT), NT
wrote:

IME relays pull in at in the region of half rated voltage, and dc
ratings are typically about half the voltage of the ac rating, which
gives an idea of how much current is determined by L and how much by
R.

---
IME, most relays (with either AC or DC coils) are guaranteed to pull
in at about 80% of their rated coil voltage, so I'm at a loss trying
to understand what you meant by: "dc ratings are typically about half
of the ac rating."

Can you elaborate, please?

When relays have dual ratings for ac and dc, its normal for the dc
voltage rating to be half the ac voltage rating.

Running your relay on 220v 60Hz it will work fine.

Knowing nothing about the contactor, other than that it's specified to
energize when 240V 50Hz is placed across the coil, your imprimatur is
premature.

I really dont agree. I do know the basics about relays, and one
normally finds that pull-in occurs at around 50% rated voltage. The OP
is welcome to test theirs to see if it behaves the usual way.

Contact closing speed will be slightly slower. Margin will be reduced,
but its only being reduced from enormous to slightly less enormous,
so its a non-issue except in very unusual situations.

It seems you've forgotten that when the armature makes, and the
magnetic circuit is closed, the inductance of the coil will rise.

I dont know why you think I've forgotten it. What's relevant here is
inductance in the closed position.

I disagree.

Since the relay is open when power is applied to the coil, it's the
open inductance (and the resistance, of course) which will determine
how much current will flow through the coil, that current being what
generates the magnetic field to start the armature on its way.

yup

Then when the relay closes, the closed inductance comes into play and
holds the armature in place until the current through the coil is
reduced to a point where the armature's return spring overcomes the
weakened magnetic field, allowing the armature to open.

yes. I guess in theory both matter, one determines closing behaviour,
the other ensures the relay doesnt overheat. In practice though the
margins are very large, and its normal to simply fix holding current
to suit the relay, and not worry about closing current, which will be
so close as to make no real world difference in all but exceptional
circumstances. But yes, we can consider both if need be.



Such being the case, the current in it will diminish,

true with all relays under all ac conditions. Theyre designed to work
that way.

reducing the
hold on the armature and making the contacts more likely to chatter.

No, its exactly how theyre designed to operate.

The vibration tolerance of
the contacts will be little affected in practice; if your environment
is harsh enough to shake the relay contact open, then you've got
bigger worries than contacts crackling.
If instead you meant you would use it on 110v 60Hz, then dont. But you
could use diodes to get a higher dc voltage and use that.

Interesting conjecture.

Where's the conjecture? I get the feeling you could do with bringing
your skills up to speed on relays.

---
Perhaps.
---

Something like this?

* * * * +-----+
120AC--|~ * +|----+
* * * * | * * | * *|
* * * * | * * | *[COIL]
* * * * | * * | * *|
120AC--|~ * -|----+
* * * * +-----+

That would work.

Not in all cases, certainly.

I'd like to see you find one single electromechanical relay that wont
work for.



Since the coil has an impedance of about 6600 ohms at 50Hz, then the
current through it will be:

* * * * * E * * *240V
* * *I = --- = ------- = 0.036A = 36mA
* * * * * Z * * 6600R

Then, since the coil has a resistance of 4800 ohms, the DC voltage
across it required to force 36mA through it would be:

* * *E = IR = 0.036A * 4800R ~ 174V.

You're not saying where you got those figures from.

---
The P&B MR5A I talked about in an earlier post, which has a 240V
50/60Hz coil, a coil resistance of 4800 ohms, an impedance of ~ 6600
ohms at 50 Hz, an open inductance of 14.5 henrys, and a closed
inductance of 16 henrys
Typically dc rating is half ac rating.

But I don't think "typical" is what we're after since we want
something that will _always_ work.

This 2:1 ratio normally is good for relays, and the OP can check his
to see if it conforms to that. If it does, the thing will always work
when subject to this formula.

FWIW, when ac is applied you get puling force plus vibration. With dc
there is no vibration component when its closed, so less holding
current is needed. How much less I've really no idea.

Some relays are fast movers capable of 100s of Hz, some are slow. Ac
relays can always work on dc, but dc ones often dont work ok on ac.



Since current is what's doing the work, my real-world example shows
that 240V 50 Hz RMS impressed across a load with an impedance of 6600
ohms will force 36mA RMS of current through the load.

Then, since it's current that's doing the work, 36mA of DC through the
coil should accomplish the same thing.
---

The peak voltage out of the bridge would be:

* * *E = RMS * sqrt(2) = 120 * 1.414 ~ 170V.

Pretty close, but at 120Hz, the reactance of the coil would increase,
limiting the current to something less than the 36mA needed to close
the armature.

The effect of the relay's inductance, when run off a BR, is simply to
smooth the current flow somewhat.

---
Yeah, I know, said so earlier, and posted a simulation showing the
ripple.
---

Mean current remains much the same.
So we're looking for 120v rms, which is what the BR would deliver.

---
But, what it won't deliver is the worst-case voltage required over the
interval required to guarantee the armature will close.

Re ripple: If the relay is designed to run on ac 50 or 60Hz, its
designed and rated to live with the current and force variations that
go along with that, 100-120 times a second. Running it on rectified
mains will only serve to reduce the current variations through the
cycle, it wont cause the relay any issues.

Re rms voltage: With my 2:1 figures, rectified 120v is spot on. With
your 174v figure, 120v is well within the 50% margin. Of course for
some uses that margin would need to be confirmed by testing before
production, and reconfirmed if a new relay type is used. Or as you
say, a cap could be added. Or for off brand consumer goods, in it
goes, relays are good for it.

However, the reactance of the coil will smooth the current and the
addition of a capacitor in parallel with the coil will remove some of
the ripple and allow the coil to see more nearly pure DC.

and overheat the relay by increasing its rms dc voltage to above 120v.

There's no such thing as "rms dc voltage",

RMS can be applied to any and every waveform, dc included. Its very
relevant when working with rectified ac, semismoothed or unsmoothed.

and if the relay is
designed to operate on AC with a certain RMS current in its coil, how
can it possibly overheat if that current is DC?

With the same current it wont, with higher curren ti will. IIRC you
proposed using 174v rms, that would be ok on your specific relay, but
not a universal solution.

NT
-----------------------
I sense a bit of cross confusion in this thread.

a)Do not the AC/DC ratings refer to the contact rating rather than the coil
rating? As with any switch, there is a big derating of contacts designed for
AC use but applied to DC- Example a typical 120V 15 A light switch would
fail at 15A 120V DC- it might work at 15A, 12V. *Older switches with good
snap contacts do much better.

No, I'm talking about coil voltage ratings.


You indicate experience for the factor of 2:1- but is this something that
translates across the AC/DC barrier?

I'm not 100% clear what you mean there. In short, many relays only
have one coil voltage rating, and its for just one of either ac or dc.
The various ones I've seen that have coil 2 ratings, one for ac one
for dc, have consistently had the dc coil rating be half the ac
voltage rating.


b) John indicates 174VDC *giving 0.036A *would be OK- for closing. However
when closed, the holding current will be 0.031A and this is the steady state
current that is involved in heating when the relay is closed. *For DC the
voltage would need to be about 150VDC [ (174*0.031/0.036)^2]. * So it
remains to be seen if that is sufficient to close the relay. *According to
you- it would be more than adequate. From John's 80% criterion it is
inadequate.- so point (c).

c) The peak force is related to the square of peak flux * For AC, this is
proportional to (Vrms/f)^2 independent of the magnetic medium. The magnetic
medium determines the corresponding peak current. While a DC current of
0.036A corresponds to an rms current of the same magnitude, and the average
force is the same, at that current, as the average force in the AC case, it
is well below the peak force (about a factor of 2, ). *This may *have have a
bearing on the relay's operation- just a conjecture.

Don Kelly
cross out to reply

Peak force would come into play when dealing with stiction, but a
relay would have to be on its very last legs for stiction to be
significant in practice.


NT

On Wed, 31 Aug 2011 09:38:16 -0700 (PDT), NT
wrote:

On Aug 31, 1:36*am, John Fields wrote:
On Tue, 30 Aug 2011 05:11:20 -0700 (PDT), NT
wrote:
On Aug 30, 12:39*pm, John Fields
wrote:
On Mon, 29 Aug 2011 07:25:23 -0700 (PDT), NT
wrote:

IME relays pull in at in the region of half rated voltage, and dc
ratings are typically about half the voltage of the ac rating, which
gives an idea of how much current is determined by L and how much by
R.

---
IME, most relays (with either AC or DC coils) are guaranteed to pull
in at about 80% of their rated coil voltage, so I'm at a loss trying
to understand what you meant by: "dc ratings are typically about half
of the ac rating."

Can you elaborate, please?

When relays have dual ratings for ac and dc, its normal for the dc
voltage rating to be half the ac voltage rating.

---
But, in this case, the OP has a relay which isn't dual-rated, but
rated only for 240V 50Hz.
---

Running your relay on 220v 60Hz it will work fine.

Knowing nothing about the contactor, other than that it's specified to
energize when 240V 50Hz is placed across the coil, your imprimatur is
premature.

I really dont agree. I do know the basics about relays, and one
normally finds that pull-in occurs at around 50% rated voltage. The OP
is welcome to test theirs to see if it behaves the usual way.

Contact closing speed will be slightly slower. Margin will be reduced,
but its only being reduced from enormous to slightly less enormous,
so its a non-issue except in very unusual situations.

It seems you've forgotten that when the armature makes, and the
magnetic circuit is closed, the inductance of the coil will rise.

I dont know why you think I've forgotten it. What's relevant here is
inductance in the closed position.

I disagree.

Since the relay is open when power is applied to the coil, it's the
open inductance (and the resistance, of course) which will determine
how much current will flow through the coil, that current being what
generates the magnetic field to start the armature on its way.

yup

---
"yup"?

Strangely, your pretentiously authoritative "yup" seems designed to
denigrate my critique as if you knew you were wrong and tried to
assign the guilt to me.
---

Then when the relay closes, the closed inductance comes into play and
holds the armature in place until the current through the coil is
reduced to a point where the armature's return spring overcomes the
weakened magnetic field, allowing the armature to open.

yes. I guess in theory both matter, one determines closing behaviour,
the other ensures the relay doesnt overheat. In practice though the
margins are very large,

---
I don't understand; what margins are you talking about?
---

and its normal to simply fix holding current
to suit the relay, and not worry about closing current, which will be
so close as to make no real world difference in all but exceptional
circumstances. But yes, we can consider both if need be.

---
Again, I'm confused.

If, as you say, it's normal to simply fix holding current to keep from
overheating the coil [by using the impedance of the coil as a current
limiter, once it's closed] then, since the strength of the magnetic
field varies, in an inverse square law kind of way, as a function of
the distance between the pole pieces, there's the very real worry
about the spacing of the pole pieces which will guarantee closure.
---

Such being the case, the current in it will diminish,

true with all relays under all ac conditions. Theyre designed to work
that way.

---
By God, maybe, but to us mortals the change in impedance is
serendipitous and all we can do with it is to work out the "must
close" to "must open" hysteresis.
---

reducing the
hold on the armature and making the contacts more likely to chatter.

No, its exactly how theyre designed to operate.

---
Are you saying that a variable current in the coil won't react against
the holding force of the armature's return spring?
---

The vibration tolerance of
the contacts will be little affected in practice; if your environment
is harsh enough to shake the relay contact open, then you've got
bigger worries than contacts crackling.
If instead you meant you would use it on 110v 60Hz, then dont. But you
could use diodes to get a higher dc voltage and use that.

Interesting conjecture.

Where's the conjecture? I get the feeling you could do with bringing
your skills up to speed on relays.

---
Perhaps.
---

Something like this?

* * * * +-----+
120AC--|~ * +|----+
* * * * | * * | * *| *
* * * * | * * | *[COIL]
* * * * | * * | * *|
120AC--|~ * -|----+
* * * * +-----+

That would work.

Not in all cases, certainly.

I'd like to see you find one single electromechanical relay that wont
work for.

---
Well, I'm certainly not going to spend any portion of the rest of my
life searching for that reclusive gem but, in the same vein, I invite
you to find any electromechanical relay with a guarantee that its
must-close voltage is half of its nominal energization voltage.
---

Since the coil has an impedance of about 6600 ohms at 50Hz, then the
current through it will be:

* * * * * E * * *240V
* * *I = --- = ------- = 0.036A = 36mA
* * * * * Z * * 6600R

Then, since the coil has a resistance of 4800 ohms, the DC voltage
across it required to force 36mA through it would be:

* * *E = IR = 0.036A * 4800R ~ 174V.

You're not saying where you got those figures from.

---
The P&B MR5A I talked about in an earlier post, which has a 240V
50/60Hz coil, a coil resistance of 4800 ohms, an impedance of ~ 6600
ohms at 50 Hz, an open inductance of 14.5 henrys, and a closed
inductance of 16 henrys

Typically dc rating is half ac rating.

But I don't think "typical" is what we're after since we want
something that will _always_ work.

This 2:1 ratio normally is good for relays, and the OP can check his
to see if it conforms to that. If it does, the thing will always work
when subject to this formula.

---
You keep saying that ratio is "normal", but when a manufacturer
specifies the "must make" voltage as 80% of the relay's rated voltage,
then the voltage across the coil must never be allowed to fall below
that when the relay is being energized.

If it's allowed to fall below that point, then even though the relay
may make, its ON delay and bounce specs will no longer be valid, with
the increased bounce time certainly being detrimental to the relay's
lifetime.
---

..
..
..

Since current is what's doing the work, my real-world example shows
that 240V 50 Hz RMS impressed across a load with an impedance of 6600
ohms will force 36mA RMS of current through the load.

Then, since it's current that's doing the work, 36mA of DC through the
coil should accomplish the same thing.
---

The peak voltage out of the bridge would be:

* * *E = RMS * sqrt(2) = 120 * 1.414 ~ 170V.

Pretty close, but at 120Hz, the reactance of the coil would increase,
limiting the current to something less than the 36mA needed to close
the armature.

The effect of the relay's inductance, when run off a BR, is simply to
smooth the current flow somewhat.

---
Yeah, I know, said so earlier, and posted a simulation showing the
ripple.
---

Mean current remains much the same.
So we're looking for 120v rms, which is what the BR would deliver.

---
But, what it won't deliver is the worst-case voltage required over the
interval required to guarantee the armature will close.

Re ripple: If the relay is designed to run on ac 50 or 60Hz, its
designed and rated to live with the current and force variations that
go along with that, 100-120 times a second. Running it on rectified
mains will only serve to reduce the current variations through the
cycle, it wont cause the relay any issues.

Re rms voltage: With my 2:1 figures, rectified 120v is spot on. With
your 174v figure, 120v is well within the 50% margin.

---
But that 50% margin is bogus since any manufacturer's guaranteed "must
make" voltage is far higher than 50%.
---

Of course for
some uses that margin would need to be confirmed by testing before
production, and reconfirmed if a new relay type is used. Or as you
say, a cap could be added. Or for off brand consumer goods, in it
goes, relays are good for it.


However, the reactance of the coil will smooth the current and the
addition of a capacitor in parallel with the coil will remove some of
the ripple and allow the coil to see more nearly pure DC.

and overheat the relay by increasing its rms dc voltage to above 120v.

There's no such thing as "rms dc voltage",

RMS can be applied to any and every waveform, dc included. Its very
relevant when working with rectified ac, semismoothed or unsmoothed.

and if the relay is
designed to operate on AC with a certain RMS current in its coil, how
can it possibly overheat if that current is DC?

With the same current it wont, with higher curren ti will. IIRC you
proposed using 174v rms,

---
No, I merely added a capacitor across the output of _your_ proposed
full wave rectified 120 VRMS 60Hz source (170V peak) in order to get
smoothed DC closer to the relay's must-make current.
---

that would be ok on your specific relay, but
not a universal solution.

---
???

Take a look at the sim again:


Version 4
SHEET 1 880 680
WIRE -144 16 -304 16
WIRE 112 16 -144 16
WIRE 448 16 288 16
WIRE 704 16 448 16
WIRE -304 80 -304 16
WIRE 288 80 288 16
WIRE 448 80 448 64
WIRE 480 80 448 80
WIRE 592 80 560 80
WIRE 704 80 704 64
WIRE 704 80 672 80
WIRE -144 112 -144 80
WIRE -112 112 -144 112
WIRE 0 112 -32 112
WIRE 112 112 112 80
WIRE 112 112 80 112
WIRE -144 160 -144 112
WIRE 112 160 112 112
WIRE 448 160 448 80
WIRE 544 160 448 160
WIRE 704 160 704 80
WIRE 704 160 608 160
WIRE -304 224 -304 160
WIRE -144 224 -304 224
WIRE 112 224 -144 224
WIRE 288 224 288 160
WIRE 448 224 288 224
WIRE 704 224 448 224
WIRE -304 272 -304 224
WIRE 288 272 288 224
FLAG -304 272 0
FLAG 288 272 0
SYMBOL ind -128 128 R270
WINDOW 0 32 56 VTop 0
WINDOW 3 5 56 VBottom 0
SYMATTR InstName L1
SYMATTR Value 15
SYMBOL voltage -304 64 R0
WINDOW 3 24 104 Invisible 0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value SINE(0 170 60)
SYMBOL diode -160 16 R0
WINDOW 0 4 -52 Left 0
WINDOW 3 -28 -24 Left 0
SYMATTR InstName D1
SYMATTR Value MUR460
SYMBOL diode 128 80 R180
WINDOW 0 1 119 Left 0
WINDOW 3 -33 84 Left 0
SYMATTR InstName D2
SYMATTR Value MUR460
SYMBOL diode 96 160 R0
WINDOW 0 3 89 Left 0
WINDOW 3 -27 118 Left 0
SYMATTR InstName D3
SYMATTR Value MUR460
SYMBOL diode -128 224 R180
WINDOW 0 2 -28 Left 0
WINDOW 3 -31 -57 Left 0
SYMATTR InstName D4
SYMATTR Value MUR460
SYMBOL res -16 128 R270
WINDOW 0 32 56 VTop 0
WINDOW 3 0 56 VBottom 0
SYMATTR InstName R1
SYMATTR Value 4800
SYMBOL ind 464 96 R270
WINDOW 0 32 56 VTop 0
WINDOW 3 5 56 VBottom 0
SYMATTR InstName L2
SYMATTR Value 15
SYMBOL voltage 288 64 R0
WINDOW 3 24 104 Invisible 0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V2
SYMATTR Value SINE(0 170 60)
SYMBOL diode 432 16 R0
WINDOW 0 4 -52 Left 0
WINDOW 3 -28 -24 Left 0
SYMATTR InstName D5
SYMATTR Value MUR460
SYMBOL diode 720 80 R180
WINDOW 0 1 119 Left 0
WINDOW 3 -33 84 Left 0
SYMATTR InstName D6
SYMATTR Value MUR460
SYMBOL diode 688 160 R0
WINDOW 0 3 89 Left 0
WINDOW 3 -27 118 Left 0
SYMATTR InstName D7
SYMATTR Value MUR460
SYMBOL diode 464 224 R180
WINDOW 0 2 -28 Left 0
WINDOW 3 -31 -57 Left 0
SYMATTR InstName D8
SYMATTR Value MUR460
SYMBOL res 576 96 R270
WINDOW 0 32 56 VTop 0
WINDOW 3 0 56 VBottom 0
SYMATTR InstName R2
SYMATTR Value 4800
SYMBOL cap 608 144 R90
WINDOW 0 0 32 VBottom 0
WINDOW 3 32 32 VTop 0
SYMATTR InstName C1
SYMATTR Value 10µ
TEXT -298 246 Left 0 !.tran .05

If the relay is spec'ed as "must make" at 80% of rated current through
the coil (~29mA), then note that with a 10µF cap in parallel with the
coil the relay will _always_ make using full-wave rectified 120V 60Hz
mains. *

--
JF
--
JF

On Aug 30, 6:59*pm, Jeff Liebermann wrote:
On Tue, 30 Aug 2011 10:55:10 -0500, Jeffrey Angus
wrote:

Hasn't anybody read the original question?

Nope. *With 5 groups in the distribution, I just assumed the original
question to not be worth reading. *Besides, some of the groups appear
to be write-only, where nobody (including me) reads the original
question.


That must be the explaination as to why so much crap has been written
on this thread!!

On Fri, 2 Sep 2011 05:47:43 -0700 (PDT), "
wrote:

On Aug 30, 6:59*pm, Jeff Liebermann wrote:
On Tue, 30 Aug 2011 10:55:10 -0500, Jeffrey Angus
wrote:

Hasn't anybody read the original question?

Nope. *With 5 groups in the distribution, I just assumed the original
question to not be worth reading. *Besides, some of the groups appear
to be write-only, where nobody (including me) reads the original
question.


That must be the explaination as to why so much crap has been written
on this thread!!

---
The addition of your three turds to this punchbowl certainly isn't
helping, is it?

--
JF

On Fri, 02 Sep 2011 09:04:24 -0500, John Fields
wrote:

The addition of your three turds to this punchbowl certainly isn't
helping, is it?

Hmmm.... 5 newsgroups.... where's my soap box?

Usenet, blogs, forums, and mailing lists are much like a trash
dumpster. At the bottom of every dumpster is a gem. All one needs to
do is dig through mountains of garbage in order to find it[1]. I try
to include some of those gems in my postings, no matter how far off
topic. As a general rule, one should not write anything that one
would not personally want to read.

In this case, there are some common indications of articles not worth
reading. My list includes:
1. One line replies. These are usually devoid of any thought,
substantiation, or useful detail.
2. Massive crossposting. This suggests that the OP hasn't bothered
to research the topic before asking, usually resulting in a question
with insufficient detail necessary for a productive answer.
3. Large numbers in the line count. This suggests that the author
has included massive quotes from the previous discussion, usually
automatically reformatted into an unreadable mess. Best to skip to
the next message in the thread, which usually includes the one line
the author has added.
4. URL only. Invariably, it's spam or self promotion.
5. All CAPS in the Subject line. That's usually spam, but sometimes
is from someone that can't type. Occasionally, it's used for its
original purpose as shouting. Unless you're into emotional content,
it's not worth reading.
6. Change of Subject line. The author doing that, instead of
starting a new topic, is usually a Usenet lawyer, more interested in
form than content. In most cases, the change of topic doesn't do much
as few readers bother to read the header. Some readers will
optionally start a new thread when the subject line changes. These
are probably worth reading, but with some suspicion as to the
motivations of the author.
7. Unsubstantiated offers of truth. These are declarations of fact
or truth based solely on the reputation or authority of the author. My
assumption is that the author usually can't prove his point if pressed
and therefore supplies no substantiation. This is difficult because
many well known authorities on a topic are too busy to lecture on
Usenet and will often assume the reader will automatically accept
their point of view based on their reputation. Personally, I don't
care what someone things. I want to know why.


[1] The few times I've asked a question on Usenet, only a small
percentage of the replies were genuinely useful. When I asked a
really complex question, with considerable detail and background,
there were no replies.
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Sep 2, 1:29*pm, John Fields wrote:
On Wed, 31 Aug 2011 09:38:16 -0700 (PDT), NT
wrote:
On Aug 31, 1:36*am, John Fields wrote:
On Tue, 30 Aug 2011 05:11:20 -0700 (PDT), NT
wrote:
On Aug 30, 12:39*pm, John Fields
wrote:
On Mon, 29 Aug 2011 07:25:23 -0700 (PDT), NT
wrote:


IME relays pull in at in the region of half rated voltage, and dc
ratings are typically about half the voltage of the ac rating, which
gives an idea of how much current is determined by L and how much by
R.

---
IME, most relays (with either AC or DC coils) are guaranteed to pull
in at about 80% of their rated coil voltage, so I'm at a loss trying
to understand what you meant by: "dc ratings are typically about half
of the ac rating."

Can you elaborate, please?

When relays have dual ratings for ac and dc, its normal for the dc
voltage rating to be half the ac voltage rating.

---
But, in this case, the OP has a relay which isn't dual-rated, but
rated only for 240V 50Hz.

We know that. I also know from observation of various mfr specs that
ac relays are normally happy on half the voltage at dc. The relays
I've seen the dual ratings on havent been significantly different to
others.


Running your relay on 220v 60Hz it will work fine.

Knowing nothing about the contactor, other than that it's specified to
energize when 240V 50Hz is placed across the coil, your imprimatur is
premature.

I really dont agree. I do know the basics about relays, and one
normally finds that pull-in occurs at around 50% rated voltage. The OP
is welcome to test theirs to see if it behaves the usual way.

Contact closing speed will be slightly slower. Margin will be reduced,
but its only being reduced from enormous to slightly less enormous,
so its a non-issue except in very unusual situations.

It seems you've forgotten that when the armature makes, and the
magnetic circuit is closed, the inductance of the coil will rise.

I dont know why you think I've forgotten it. What's relevant here is
inductance in the closed position.

I disagree.

Since the relay is open when power is applied to the coil, it's the
open inductance (and the resistance, of course) which will determine
how much current will flow through the coil, that current being what
generates the magnetic field to start the armature on its way.

yup

"yup"?

Strangely, your *pretentiously authoritative "yup" seems designed to
denigrate my critique as if you knew you were wrong and tried to
assign the guilt to me.

Yup just means yes, it indicates agreement. Nothing else.


Then when the relay closes, the closed inductance comes into play and
holds the armature in place until the current through the coil is
reduced to a point where the armature's return spring overcomes the
weakened magnetic field, allowing the armature to open.

yes. I guess in theory both matter, one determines closing behaviour,
the other ensures the relay doesnt overheat. In practice though the
margins are very large,

I don't understand; what margins are you talking about?

The coil v/i margins, the difference between what works and the
nominal voltage rating


and its normal to simply fix holding current
to suit the relay, and not worry about closing current, which will be
so close as to make no real world difference in all but exceptional
circumstances. But yes, we can consider both if need be.

---
Again, I'm confused.

If, as you say, it's normal to simply fix holding current to keep from
overheating the coil [by using the impedance of the coil as a current
limiter, once it's closed] then, since the strength of the magnetic
field varies, in an inverse square law kind of way, as a function of
the distance between the pole pieces, there's the very real worry
about the spacing of the pole pieces which will guarantee closure.

a design question for the relay manufacturer perhaps, its a non-issue
for us


Such being the case, the current in it will diminish,

true with all relays under all ac conditions. Theyre designed to work
that way.

---
By God, maybe, but to us mortals the change in impedance is
serendipitous and all we can do with it is to work out the "must
close" to "must open" hysteresis.

One seldom need worry about the must open rating. The must close and
wont overheat points are what counts in 99.9% of applications.


reducing the
hold on the armature and making the contacts more likely to chatter..

No, its exactly how theyre designed to operate.

---
Are you saying that a variable current in the coil won't react against
the holding force of the armature's return spring?

I'm saying it already taken into account in teh design of the relay,
its an ac relay. All we need do is give it enough current, but not too
much.


The vibration tolerance of
the contacts will be little affected in practice; if your environment
is harsh enough to shake the relay contact open, then you've got
bigger worries than contacts crackling.
If instead you meant you would use it on 110v 60Hz, then dont. But you
could use diodes to get a higher dc voltage and use that.

Interesting conjecture.

Where's the conjecture? I get the feeling you could do with bringing
your skills up to speed on relays.

---
Perhaps.
---

Something like this?

* * * * +-----+
120AC--|~ * +|----+
* * * * | * * | * *| *
* * * * | * * | *[COIL]
* * * * | * * | * *|
120AC--|~ * -|----+
* * * * +-----+

That would work.

Not in all cases, certainly.

I'd like to see you find one single electromechanical relay that wont
work for.

---
Well, I'm certainly not going to spend any portion of the rest of my
life searching for that reclusive gem but, in the same vein, I invite
you to find any electromechanical relay with a guarantee that its
must-close voltage is half of its nominal energization voltage.

I'm talking about what relays actually do in the real world. Reality
and mfr specs often dont match.


Since the coil has an impedance of about 6600 ohms at 50Hz, then the
current through it will be:

* * * * * E * * *240V
* * *I = --- = ------- = 0.036A = 36mA
* * * * * Z * * 6600R

Then, since the coil has a resistance of 4800 ohms, the DC voltage
across it required to force 36mA through it would be:

* * *E = IR = 0.036A * 4800R ~ 174V.

You're not saying where you got those figures from.

---
The P&B MR5A I talked about in an earlier post, which has a 240V
50/60Hz coil, a coil resistance of 4800 ohms, an impedance of ~ 6600
ohms at 50 Hz, an open inductance of 14.5 henrys, and a closed
inductance of 16 henrys

Typically dc rating is half ac rating.

But I don't think "typical" is what we're after since we want
something that will _always_ work.

This 2:1 ratio normally is good for relays, and the OP can check his
to see if it conforms to that. If it does, the thing will always work
when subject to this formula.

---
You keep saying that ratio is "normal", but when a manufacturer
specifies the "must make" voltage as 80% of the relay's rated voltage,
then the voltage across the coil must never be allowed to fall below
that when the relay is being energized.

I have to say that is false. Its fairly normal engineering practice to
use parts outside of mfr's specs so long as their effectiveness in
such conditions is verified, they can reasonably be counted on to
continue to operate satisfactorily, and so long as the level of
reliability that gives is sufficient for the app. And in this case the
OP has good motivation to do so.


If it's allowed to fall below that point, then even though the relay
may make, its ON delay and bounce specs will no longer be valid, with
the increased bounce time certainly being detrimental to the relay's
lifetime. * *

On delay specs are seldom critical. If they are then of course you'll
hit the coil with full rated v - or as I used to do at times, much
higher for a small fraction of a second to get it switching faster.

Bounce specs, again whether its ok depends on the app, and effect on
lifetime depends on whats being switched, and what lifetime is in fact
required of the part.


Since current is what's doing the work, my real-world example shows
that 240V 50 Hz RMS impressed across a load with an impedance of 6600
ohms will force 36mA RMS of current through the load.

Then, since it's current that's doing the work, 36mA of DC through the
coil should accomplish the same thing.
---

The peak voltage out of the bridge would be:

* * *E = RMS * sqrt(2) = 120 * 1.414 ~ 170V.

Pretty close, but at 120Hz, the reactance of the coil would increase,
limiting the current to something less than the 36mA needed to close
the armature.

The effect of the relay's inductance, when run off a BR, is simply to
smooth the current flow somewhat.

---
Yeah, I know, said so earlier, and posted a simulation showing the
ripple.
---

Mean current remains much the same.
So we're looking for 120v rms, which is what the BR would deliver.

---
But, what it won't deliver is the worst-case voltage required over the
interval required to guarantee the armature will close.

Re ripple: If the relay is designed to run on ac 50 or 60Hz, its
designed and rated to live with the current and force variations that
go along with that, 100-120 times a second. Running it on rectified
mains will only serve to reduce the current variations through the
cycle, it wont cause the relay any issues.

Re rms voltage: With my 2:1 figures, rectified 120v is spot on. With
your 174v figure, 120v is well within the 50% margin.

But that 50% margin is bogus since any manufacturer's guaranteed "must
make" voltage is far higher than 50%.

Its not bogus at all. If you really want to settle this, take a pile
of random relays and test what v they actually do close at. Then we
can discuss why what you find and what the mfr says are different.

You're stuck on mfr spec when the situation is that the OP is strongly
motivated to use the part outside of its mfr spec. Engineers do that.


Of course for
some uses that margin would need to be confirmed by testing before
production, and reconfirmed if a new relay type is used. Or as you
say, a cap could be added. Or for off brand consumer goods, in it
goes, relays are good for it.

However, the reactance of the coil will smooth the current and the
addition of a capacitor in parallel with the coil will remove some of
the ripple and allow the coil to see more nearly pure DC.

and overheat the relay by increasing its rms dc voltage to above 120v..

There's no such thing as "rms dc voltage",

RMS can be applied to any and every waveform, dc included. Its very
relevant when working with rectified ac, semismoothed or unsmoothed.

and if the relay is
designed to operate on AC with a certain RMS current in its coil, how
can it possibly overheat if that current is DC?

With the same current it wont, with higher curren ti will. IIRC you
proposed using 174v rms,

No, I merely added a capacitor across the output of _your_ proposed
full wave rectified 120 VRMS 60Hz source (170V peak) in order to get
smoothed DC closer to the relay's must-make current.

fwliw I said use diodes, you came back with a FW BR. I dont think it
matters.


that would be ok on your specific relay, but
not a universal solution.

???

Your proposd BR+C delivers the right i for one specific relay. For
some relays it will fry them.


NT

Snipped a lot of repetitious, self serving nonsense.

and if the relay is
designed to operate on AC with a certain RMS current in its coil, how
can it possibly overheat if that current is DC?

With the same current it wont, with higher curren ti will. IIRC you
proposed using 174v rms,

No, I merely added a capacitor across the output of _your_ proposed
full wave rectified 120 VRMS 60Hz source (170V peak) in order to get
smoothed DC closer to the relay's must-make current.

fwliw I said use diodes, you came back with a FW BR. I dont think it
matters.

---
Then show me your circuit.

Just in case you've forgotten, your suggestion was to use a 240V AC
relay using diodes and 120V mains.
---

that would be ok on your specific relay, but
not a universal solution.

???

Your proposd BR+C delivers the right i for one specific relay. For
some relays it will fry them.

---
Show me.

--
JF

On Tue, 30 Aug 2011 09:49:01 -0700, Rich Grise
wrote:

John Fields wrote:
On Tue, 30 Aug 2011 02:58:19 +0000 (UTC), David Lesher
John Fields writes:

I have an old P&B MR5A here with a 240V 50/60Hz coil.

The coil has a resistance of 4800 ohms, and an open inductance of 14.5
henrys, so it has an impedance of 6616 ohms at 50 Hz, and 7270 ohms at
60 Hz.

What's the inductance while closed?

16 henries, but that measurement was made by closing the armature
manually.

If there's any real interest I can measure it energized.

Well, I guess that depends on what you mean by "real interest" - I'd be
interested in seeing your experimental results, but that's just because
I like seeing experimental results. ;-)

---
OK. :-)

First, in order to measure the coil's unexcited inductance, I set up
the experiment like this:



+---------+ R1 +-----+
| SINE OUT|--[30K]---+----|VERT |
| | | | |
| | [0.1µF] | |
| | | | |
| | [DUT] | |
| | | | |
| GND|----------+----|GND |
+---------+ +-----+
FUNCTION SCOPE
GRNERATOR


I then cranked up the generator's output to get a decent display on
the scope and changed frequency until I got a suckout on the scope.

That was at 110Hz so, since in a resonant circuit the reactances
cancel, the suckout was caused by the voltage divider formed by R1 and
the resistance of the coil.

The reactance of the cap at that frequency was:

1 1
Xc = --------- = ---------------------- = 14476 ohms ~ 14.5kohms
2pi f C 6.28 * 110Hz * 1e-7F

Then, since the reactances of the capacitance and the inductance are
equal (but of opposite sign) at resonance, we can find the inductance
with:


Xl 14500R
L = ------- = -------------- = 21 henrys
2pi f 6.28 * 110Hz



Next, I measured the coil's DC resistance, found it to be 4900
ohms,and in order to measure the coil's excited inductance, set up an
experiment, like this, in order to measure the coil current at 240V
60Hz:

0-120V
/
VARIAC / 0-480V 240V
+------+ / / /
120AC--| HOT|--+ +--[AC AMPS]--+-------+
| | | | | |
| | P||S | |
| | R||E [DUT] [AC VOLTS]
| | I||C | |
| | | | | |
120AC--|-NEUT-|--+ +-------------+-------+
+------+ BFT


I got 15mA with 240V across the coil.


Now, to find the impedance of the coil we can say:

E 240V
Z = --- = -------- = 16000 ohms.
I 0.015A

Then the inductive reactance of the coil will be:

Xl = sqrt(Z² - R²) = sqrt(2.56e8 - 2.4e7) ~ 15200 ohms

and, finally, the inductance:

Xl
L = ------- = 40.3 henrys
2pi f

TADA!

--
JF

On Sep 2, 3:04*pm, John Fields wrote:
On Fri, 2 Sep 2011 05:47:43 -0700 (PDT), "

wrote:
On Aug 30, 6:59*pm, Jeff Liebermann wrote:
On Tue, 30 Aug 2011 10:55:10 -0500, Jeffrey Angus
wrote:

Hasn't anybody read the original question?

Nope. *With 5 groups in the distribution, I just assumed the original
question to not be worth reading. *Besides, some of the groups appear
to be write-only, where nobody (including me) reads the original
question.

That must be the explaination as to why so much crap has been written
on this thread!!

---
The addition of your three turds to this punchbowl certainly isn't
helping, is it?

--
JF

Well they might if you actually read them, I have actually given the
op the correct answer, I actually read the question. Of course your
free to ramble on about relays instead of contactors if you like.

On Sep 2, 4:23*pm, Jeff Liebermann wrote:
Hmmm.... 5 newsgroups.... where's my soap box?

Usenet, blogs, forums, and mailing lists are much like a trash
dumpster. *At the bottom of every dumpster is a gem. *All one needs to
do is dig through mountains of garbage in order to find it[1]. *I try
to include some of those gems in my postings, no matter how far off
topic.

If it's off topic what use is it?


*As a general rule, one should not write anything that one
would not personally want to read.

In this case, there are some common indications of articles not worth
reading. *My list includes:
1. *One line replies. *These are usually devoid of any thought,
substantiation, or useful detail.

One liners often get straight to the point, many nonsence posts need
that kind of answer.

2. *Massive crossposting. *This suggests that the OP hasn't bothered
to research the topic before asking, usually resulting in a question
with insufficient detail necessary for a productive answer.

Most OPs havent done any research, if they had they wouldnt need to
post in the first place.

7. *Unsubstantiated offers of truth.

Well they all unsubstantiated, some are accurate but most are not,
some are total nonsence.

*These are declarations of fact
or truth based solely on the reputation or authority of the author. My
assumption is that the author usually can't prove his point if pressed
and therefore supplies no substantiation.

He cant because he doesnt know what he's talking about mostly.

*This is difficult because
many well known authorities on a topic are too busy to lecture on
Usenet and will often assume the reader will automatically accept
their point of view based on their reputation.

They are only well known because they post alot, that doesn't make
them expert or an authority in any way.

*Personally, I don't
care what someone things. *I want to know why.

Well google it then.


[1] *The few times I've asked a question on Usenet, only a small
percentage of the replies were genuinely useful.

Your asking the wrong question then.


*When I asked a
really complex question, with considerable detail and background,
there were no replies.

Who can be bothered to read all that? You need to get your question
consice, you need to independently verify any answer you get. This is
not the place to learn anything except maybe to do your research
somewhere else.


--
Jeff Liebermann * *
150 Felker St #D * *http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann * * AE6KS * *831-336-2558

On Fri, 2 Sep 2011 15:42:28 -0700 (PDT), "
wrote:

On Sep 2, 3:04*pm, John Fields wrote:
On Fri, 2 Sep 2011 05:47:43 -0700 (PDT), "

wrote:
On Aug 30, 6:59*pm, Jeff Liebermann wrote:
On Tue, 30 Aug 2011 10:55:10 -0500, Jeffrey Angus
wrote:

Hasn't anybody read the original question?

Nope. *With 5 groups in the distribution, I just assumed the original
question to not be worth reading. *Besides, some of the groups appear
to be write-only, where nobody (including me) reads the original
question.

That must be the explaination as to why so much crap has been written
on this thread!!

---
The addition of your three turds to this punchbowl certainly isn't
helping, is it?

--
JF

Well they might if you actually read them, I have actually given the
op the correct answer,

---
Really?

Here are your previous posts to this thread:

Your first:

"Finally someone comes up with the correct answer."

Your second:

"Oh they don't do practical here! It's rare for them to get it right
either, this thread is no exception. Some of them even advertise their
place of work! I wonder how much business that has cost them."

Your third:

"That must be the explaination as to why so much crap has been written
on this thread!!"

Which of those gives the correct answer to the OP?
---

I actually read the question.

---
More's the pity then, since you obviously didn't understand it.
---

Of course your free to ramble on about relays instead of contactors if you like.

---
If you have any capacity for learning, you need to smart up on
reasoning and punctuation before you start talking about **** you know
nothing about.

Just to help you along, here's a clue:

All contactors are relays, but not all relays are contactors.

--
JF

On Fri, 2 Sep 2011 16:10:42 -0700 (PDT), "
wrote:

On Sep 2, 4:23*pm, Jeff Liebermann wrote:
Hmmm.... 5 newsgroups.... where's my soap box?

Usenet, blogs, forums, and mailing lists are much like a trash
dumpster. *At the bottom of every dumpster is a gem. *All one needs to
do is dig through mountains of garbage in order to find it[1]. *I try
to include some of those gems in my postings, no matter how far off
topic.

If it's off topic what use is it?


*As a general rule, one should not write anything that one
would not personally want to read.

In this case, there are some common indications of articles not worth
reading. *My list includes:
1. *One line replies. *These are usually devoid of any thought,
substantiation, or useful detail.

One liners often get straight to the point, many nonsence posts need
that kind of answer.

2. *Massive crossposting. *This suggests that the OP hasn't bothered
to research the topic before asking, usually resulting in a question
with insufficient detail necessary for a productive answer.

Most OPs havent done any research, if they had they wouldnt need to
post in the first place.

7. *Unsubstantiated offers of truth.

Well they all unsubstantiated, some are accurate but most are not,
some are total nonsence.

*These are declarations of fact
or truth based solely on the reputation or authority of the author. My
assumption is that the author usually can't prove his point if pressed
and therefore supplies no substantiation.

He cant because he doesnt know what he's talking about mostly.

*This is difficult because
many well known authorities on a topic are too busy to lecture on
Usenet and will often assume the reader will automatically accept
their point of view based on their reputation.

They are only well known because they post alot, that doesn't make
them expert or an authority in any way.

*Personally, I don't
care what someone things. *I want to know why.

Well google it then.


[1] *The few times I've asked a question on Usenet, only a small
percentage of the replies were genuinely useful.

Your asking the wrong question then.


*When I asked a
really complex question, with considerable detail and background,
there were no replies.

Who can be bothered to read all that? You need to get your question
consice, you need to independently verify any answer you get. This is
not the place to learn anything except maybe to do your research
somewhere else.

---
Another of the illiterati bums rears up and flaunts his midget
intellect while standing on soggy ground.

--
JF

On Monday, August 29, 2011 7:25:23 AM UTC-7, NT wrote:
On Aug 29, 7:21*am, DaveC wrote:
I may be able to obtain a very small 2-pole 240 vac contactor I need rated
for 50 Hz only.

If I install it in N. America, what's the implication? Is the hold-in
magnetism less than if it were 60 Hz?


If instead you meant you would use it on 110v 60Hz, then dont. But you
could use diodes to get a higher dc voltage and use that.

NO NO NO!
DC excitation of an AC-rated coil is never a good idea.
DC coils and DC-activated relays are designed very differently
from their AC cousins.

On Sep 3, 12:55*am, John Fields wrote:


---
Another of the illiterati bums rears up and flaunts his midget
intellect while standing on soggy ground.

--
JF- Hide quoted text -

- Show quoted text -

Thats an outstanding insult John, must have taken you a while to come
up with, or is it a quote you stole?

"whit3rd" wrote in message
...
On Monday, August 29, 2011 7:25:23 AM UTC-7, NT wrote:
On Aug 29, 7:21 am, DaveC wrote:
I may be able to obtain a very small 2-pole 240 vac contactor I need
rated
for 50 Hz only.

If I install it in N. America, what's the implication? Is the hold-in
magnetism less than if it were 60 Hz?


If instead you meant you would use it on 110v 60Hz, then dont. But you
could use diodes to get a higher dc voltage and use that.

NO NO NO!
DC excitation of an AC-rated coil is never a good idea.
DC coils and DC-activated relays are designed very differently
from their AC cousins.

vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

As long as you alter the voltage to take into account no inductive effect,
its probably not as bad as running a DC contactor with AC.

On Sep 2, 8:41*pm, John Fields wrote:
Snipped a lot of repetitious, self serving nonsense.

and if the relay is
designed to operate on AC with a certain RMS current in its coil, how
can it possibly overheat if that current is DC?

With the same current it wont, with higher curren ti will. IIRC you
proposed using 174v rms,

No, I merely added a capacitor across the output of _your_ proposed
full wave rectified 120 VRMS 60Hz source (170V peak) in order to get
smoothed DC closer to the relay's must-make current.

fwliw I said use diodes, you came back with a FW BR. I dont think it
matters.

---
Then show me your circuit.

Just in case you've forgotten, your suggestion was to use a 240V AC
relay using diodes and 120V mains.
---

that would be ok on your specific relay, but
not a universal solution.

???

Your proposd BR+C delivers the right i for one specific relay. For
some relays it will fry them.

---
Show me.

If you want to go get some specs of other relays, you can. This is
starting to get silly.

On Sat, 3 Sep 2011 10:13:51 -0700 (PDT), NT
wrote:

On Sep 2, 8:41*pm, John Fields wrote:
Snipped a lot of repetitious, self serving nonsense.

and if the relay is
designed to operate on AC with a certain RMS current in its coil, how
can it possibly overheat if that current is DC?

With the same current it wont, with higher curren ti will. IIRC you
proposed using 174v rms,

No, I merely added a capacitor across the output of _your_ proposed
full wave rectified 120 VRMS 60Hz source (170V peak) in order to get
smoothed DC closer to the relay's must-make current.

fwliw I said use diodes, you came back with a FW BR. I dont think it
matters.

---
Then show me your circuit.

Just in case you've forgotten, your suggestion was to use a 240V AC
relay using diodes and 120V mains.
---

that would be ok on your specific relay, but
not a universal solution.

???

Your proposd BR+C delivers the right i for one specific relay. For
some relays it will fry them.

---
Show me.

If you want to go get some specs of other relays, you can. This is
starting to get silly.

---
Translation: "I can do neither, but let me see what I can do to duck
out of here without losing too much face."

--
JF

On Saturday, September 3, 2011 7:45:47 AM UTC-7, Ian Field wrote:
"whit3rd" wrote in message


NO NO NO!
DC excitation of an AC-rated coil is never a good idea.

As long as you alter the voltage to take into account no inductive effect,
its probably not as bad as running a DC contactor with AC.

There's a subtle difference, though, in an iron pole piece that gets
permanently magnetized by repeated DC excitation, and the same
pole piece that gets AC and is repeatedly demagnetized. I'd worry
about the DC causing, maybe after weeks, a failure of a perfectly
good AC component.

The 'no inductive effect' means that only the wire resistance, not the
resistance plus inductance, limits field current. That means the
field current with DC isn't predictably proportioned to the field
current with AC (though THAT could be quickly tested).

"NT" wrote in message
...

-----------------------
I sense a bit of cross confusion in this thread.

a)Do not the AC/DC ratings refer to the contact rating rather than the
coil
rating? As with any switch, there is a big derating of contacts designed
for
AC use but applied to DC- Example a typical 120V 15 A light switch would
fail at 15A 120V DC- it might work at 15A, 12V. Older switches with good
snap contacts do much better.

No, I'm talking about coil voltage ratings.


You indicate experience for the factor of 2:1- but is this something that
translates across the AC/DC barrier?

I'm not 100% clear what you mean there. In short, many relays only
have one coil voltage rating, and its for just one of either ac or dc.
The various ones I've seen that have coil 2 ratings, one for ac one
for dc, have consistently had the dc coil rating be half the ac
voltage rating.


b) John indicates 174VDC giving 0.036A would be OK- for closing. However
when closed, the holding current will be 0.031A and this is the steady
state
current that is involved in heating when the relay is closed. For DC the
voltage would need to be about 150VDC [ (174*0.031/0.036)^2]. So it
remains to be seen if that is sufficient to close the relay. According to
you- it would be more than adequate. From John's 80% criterion it is
inadequate.- so point (c).

c) The peak force is related to the square of peak flux For AC, this is
proportional to (Vrms/f)^2 independent of the magnetic medium. The
magnetic
medium determines the corresponding peak current. While a DC current of
0.036A corresponds to an rms current of the same magnitude, and the
average
force is the same, at that current, as the average force in the AC case,
it
is well below the peak force (about a factor of 2, ). This may have have
a
bearing on the relay's operation- just a conjecture.

Don Kelly
cross out to reply

Peak force would come into play when dealing with stiction, but a
relay would have to be on its very last legs for stiction to be
significant in practice.


NT

Thank you.

Possibly the DC rating is lower because of the lower impedance (In the
example, with the coil closed the resistance cited is about 60 % of the 60
Hz impedance and the same current is wanted.

Don Kelly
cross out to reply

On Sep 3, 6:50*pm, John Fields wrote:
On Sat, 3 Sep 2011 10:13:51 -0700 (PDT), NT
wrote:



On Sep 2, 8:41*pm, John Fields wrote:
Snipped a lot of repetitious, self serving nonsense.

and if the relay is
designed to operate on AC with a certain RMS current in its coil, how
can it possibly overheat if that current is DC?

With the same current it wont, with higher curren ti will. IIRC you
proposed using 174v rms,

No, I merely added a capacitor across the output of _your_ proposed
full wave rectified 120 VRMS 60Hz source (170V peak) in order to get
smoothed DC closer to the relay's must-make current.

fwliw I said use diodes, you came back with a FW BR. I dont think it
matters.

---
Then show me your circuit.

Just in case you've forgotten, your suggestion was to use a 240V AC
relay using diodes and 120V mains.
---

that would be ok on your specific relay, but
not a universal solution.

???

Your proposd BR+C delivers the right i for one specific relay. For
some relays it will fry them.

---
Show me.

If you want to go get some specs of other relays, you can. This is
starting to get silly.

---
Translation: *"I can do neither, but let me see what I can do to duck
out of here without losing too much face."

translation: if you want to go teach yoursef, youre free to. I'm not
puting however many hours in for you for free.

On Sep 3, 12:41*am, John Fields wrote:
On Fri, 2 Sep 2011 15:42:28 -0700 (PDT), "





wrote:
On Sep 2, 3:04*pm, John Fields wrote:
On Fri, 2 Sep 2011 05:47:43 -0700 (PDT), "

wrote:
On Aug 30, 6:59*pm, Jeff Liebermann wrote:
On Tue, 30 Aug 2011 10:55:10 -0500, Jeffrey Angus
wrote:

Hasn't anybody read the original question?

Nope. *With 5 groups in the distribution, I just assumed the original
question to not be worth reading. *Besides, some of the groups appear
to be write-only, where nobody (including me) reads the original
question.

That must be the explaination as to why so much crap has been written
on this thread!!

---
The addition of your three turds to this punchbowl certainly isn't
helping, is it?

--
JF

Well they might if you actually read them, I have actually given the
op the correct answer,

---
Really?

Here are your previous posts to this thread:

Your first:

"Finally someone comes up with the correct answer."

Your second:

"Oh they don't do practical here! It's rare for them to get it right
either, this thread is no exception. Some of them even advertise their
place of work! I wonder how much business that has cost them."

Your third:

"That must be the explaination as to why so much crap has been written
on this thread!!"

Which of those gives the correct answer to the OP?

Err the first, maybe you didnt read the post it was replying to.

---

I actually read the question.

---
More's the pity then, since you obviously didn't understand it.

What do you think i didn't understand?


---

Of course your free to ramble on about relays instead of contactors if you like.

---
If you have any capacity for learning, you need to smart up on
reasoning and punctuation before you start talking about **** you know
nothing about.

smarten up John



Just to help you along, here's a clue:

All contactors are relays, but not all relays are contactors.

No there not dopey.



--
JF- Hide quoted text -

- Show quoted text -

On Sep 3, 8:57*pm, NT wrote:
On Sep 3, 6:50*pm, John Fields wrote:





On Sat, 3 Sep 2011 10:13:51 -0700 (PDT), NT
wrote:

On Sep 2, 8:41*pm, John Fields wrote:
Snipped a lot of repetitious, self serving nonsense.

and if the relay is
designed to operate on AC with a certain RMS current in its coil, how
can it possibly overheat if that current is DC?

With the same current it wont, with higher curren ti will. IIRC you
proposed using 174v rms,

No, I merely added a capacitor across the output of _your_ proposed
full wave rectified 120 VRMS 60Hz source (170V peak) in order to get
smoothed DC closer to the relay's must-make current.

fwliw I said use diodes, you came back with a FW BR. I dont think it
matters.

---
Then show me your circuit.

Just in case you've forgotten, your suggestion was to use a 240V AC
relay using diodes and 120V mains.
---

that would be ok on your specific relay, but
not a universal solution.

???

Your proposd BR+C delivers the right i for one specific relay. For
some relays it will fry them.

---
Show me.

If you want to go get some specs of other relays, you can. This is
starting to get silly.

---
Translation: *"I can do neither, but let me see what I can do to duck
out of here without losing too much face."

translation: if you want to go teach yoursef, youre free to. I'm not
puting however many hours in for you for free.

TRANSLATION: I'M JUST SAYING.

On Sat, 3 Sep 2011 17:57:46 -0700 (PDT), NT
wrote:

On Sep 3, 6:50*pm, John Fields wrote:
On Sat, 3 Sep 2011 10:13:51 -0700 (PDT), NT
wrote:



On Sep 2, 8:41*pm, John Fields wrote:
Snipped a lot of repetitious, self serving nonsense.

and if the relay is
designed to operate on AC with a certain RMS current in its coil, how
can it possibly overheat if that current is DC?

With the same current it wont, with higher curren ti will. IIRC you
proposed using 174v rms,

No, I merely added a capacitor across the output of _your_ proposed
full wave rectified 120 VRMS 60Hz source (170V peak) in order to get
smoothed DC closer to the relay's must-make current.

fwliw I said use diodes, you came back with a FW BR. I dont think it
matters.

---
Then show me your circuit.

Just in case you've forgotten, your suggestion was to use a 240V AC
relay using diodes and 120V mains.
---

that would be ok on your specific relay, but
not a universal solution.

???

Your proposd BR+C delivers the right i for one specific relay. For
some relays it will fry them.

---
Show me.

If you want to go get some specs of other relays, you can. This is
starting to get silly.

---
Translation: *"I can do neither, but let me see what I can do to duck
out of here without losing too much face."

translation: if you want to go teach yoursef, youre free to. I'm not
puting however many hours in for you for free.

---
You're the one who made the accusations, copycat, so it's up to you to
prove them.

The fact is, you can't, since you have no working circuit which isn't
a full-wave bridge yet uses more than one diode, and there is no relay
with a 240VAC coil which will fry when driven with perfectly rectified
and smoothed 120VAC.

If you had either you'd post proof but, instead, you choose to be
ignominious.

--
JF

On Sat, 3 Sep 2011 20:01:00 -0700 (PDT), "
wrote:

On Sep 3, 12:41*am, John Fields wrote:
On Fri, 2 Sep 2011 15:42:28 -0700 (PDT), "





wrote:
On Sep 2, 3:04*pm, John Fields wrote:
On Fri, 2 Sep 2011 05:47:43 -0700 (PDT), "

wrote:
On Aug 30, 6:59*pm, Jeff Liebermann wrote:
On Tue, 30 Aug 2011 10:55:10 -0500, Jeffrey Angus
wrote:

Hasn't anybody read the original question?

Nope. *With 5 groups in the distribution, I just assumed the original
question to not be worth reading. *Besides, some of the groups appear
to be write-only, where nobody (including me) reads the original
question.

That must be the explaination as to why so much crap has been written
on this thread!!

---
The addition of your three turds to this punchbowl certainly isn't
helping, is it?

--
JF

Well they might if you actually read them, I have actually given the
op the correct answer,

---
Really?

Here are your previous posts to this thread:

Your first:

"Finally someone comes up with the correct answer."

Your second:

"Oh they don't do practical here! It's rare for them to get it right
either, this thread is no exception. Some of them even advertise their
place of work! I wonder how much business that has cost them."

Your third:

"That must be the explaination as to why so much crap has been written
on this thread!!"

Which of those gives the correct answer to the OP?

Err the first, maybe you didnt read the post it was replying to.

---

I actually read the question.

---
More's the pity then, since you obviously didn't understand it.

What do you think i didn't understand?


---

Of course your free to ramble on about relays instead of contactors if you like.

---
If you have any capacity for learning, you need to smart up on
reasoning and punctuation before you start talking about **** you know
nothing about.

smarten up John



Just to help you along, here's a clue:

All contactors are relays, but not all relays are contactors.

No there not dopey.

---
Goodbye, inept troll...

PLONK

--
JF

On Sep 4, 11:06*am, John Fields wrote:
On Sat, 3 Sep 2011 17:57:46 -0700 (PDT), NT
wrote:
On Sep 3, 6:50*pm, John Fields wrote:
On Sat, 3 Sep 2011 10:13:51 -0700 (PDT), NT
wrote:
On Sep 2, 8:41*pm, John Fields wrote:
Snipped a lot of repetitious, self serving nonsense.

and if the relay is
designed to operate on AC with a certain RMS current in its coil, how
can it possibly overheat if that current is DC?

With the same current it wont, with higher curren ti will. IIRC you
proposed using 174v rms,

No, I merely added a capacitor across the output of _your_ proposed
full wave rectified 120 VRMS 60Hz source (170V peak) in order to get
smoothed DC closer to the relay's must-make current.

fwliw I said use diodes, you came back with a FW BR. I dont think it
matters.

---
Then show me your circuit.

Just in case you've forgotten, your suggestion was to use a 240V AC
relay using diodes and 120V mains.
---

that would be ok on your specific relay, but
not a universal solution.

???

Your proposd BR+C delivers the right i for one specific relay. For
some relays it will fry them.

---
Show me.

If you want to go get some specs of other relays, you can. This is
starting to get silly.

---
Translation: *"I can do neither, but let me see what I can do to duck
out of here without losing too much face."

translation: if you want to go teach yoursef, youre free to. I'm not
puting however many hours in for you for free.

---
You're the one who made the accusations, copycat, so it's up to you to
prove them.

I havent made any accusations


The fact is, you can't, since you have no working circuit which isn't
a full-wave bridge yet uses more than one diode,

what are you talking about

and there is no relay
with a 240VAC coil which will fry when driven with perfectly rectified
and smoothed 120VAC.

So your sample of one proves it for all relays? Do all have the same L/
R ratio?


If you had either you'd post proof but, instead, you choose to be
ignominious.

You get stupid and make personal insults, AND expect the person you
insult to spend time for you for nothing. No, it is not my job, like
everyone here I only write when I have time & feel like it, and its
not my concern whether you look stuff up or not.

On Sun, 4 Sep 2011 06:50:56 -0700 (PDT), NT
wrote:

On Sep 4, 11:06*am, John Fields wrote:
On Sat, 3 Sep 2011 17:57:46 -0700 (PDT), NT
wrote:
On Sep 3, 6:50*pm, John Fields wrote:
On Sat, 3 Sep 2011 10:13:51 -0700 (PDT), NT
wrote:
On Sep 2, 8:41*pm, John Fields wrote:
Snipped a lot of repetitious, self serving nonsense.

and if the relay is
designed to operate on AC with a certain RMS current in its coil, how
can it possibly overheat if that current is DC?

With the same current it wont, with higher curren ti will. IIRC you
proposed using 174v rms,

No, I merely added a capacitor across the output of _your_ proposed
full wave rectified 120 VRMS 60Hz source (170V peak) in order to get
smoothed DC closer to the relay's must-make current.

fwliw I said use diodes, you came back with a FW BR. I dont think it
matters.

---
Then show me your circuit.

Just in case you've forgotten, your suggestion was to use a 240V AC
relay using diodes and 120V mains.
---

that would be ok on your specific relay, but
not a universal solution.

???

Your proposd BR+C delivers the right i for one specific relay. For
some relays it will fry them.

---
Show me.

If you want to go get some specs of other relays, you can. This is
starting to get silly.

---
Translation: *"I can do neither, but let me see what I can do to duck
out of here without losing too much face."

translation: if you want to go teach yoursef, youre free to. I'm not
puting however many hours in for you for free.

---
You're the one who made the accusations, copycat, so it's up to you to
prove them.

I havent made any accusations

---
OK, then, unsubstantiated claims.
---


The fact is, you can't, since you have no working circuit which isn't
a full-wave bridge yet uses more than one diode,

what are you talking about

---
You don't know?

By claiming to use "diodes" the meaning is taken that more than one
will be used.

My request was simply to show the circuit.

Can you?
---

and there is no relay
with a 240VAC coil which will fry when driven with perfectly rectified
and smoothed 120VAC.

So your sample of one proves it for all relays? Do all have the same L/
R ratio?

---
Unless you can prove my claim is wrong, somehow, my claim stands
undefeated.
---

If you had either you'd post proof but, instead, you choose to be
ignominious.

You get stupid and make personal insults,

---
PKB???
---

AND expect the person you
insult to spend time for you for nothing.

---
I really expect nothing from you, and you may find being called
ignominious insulting, but I was just stating a fact.
---

No, it is not my job, like
everyone here I only write when I have time & feel like it, and its
not my concern whether you look stuff up or not.

---
Well, since it's not my job to do _your_ legwork, and you refuse to
back up what you claim to be true, this discussion is over.

--
JF

On Sep 4, 11:10*am, John Fields wrote:
On Sat, 3 Sep 2011 20:01:00 -0700 (PDT), "





wrote:
On Sep 3, 12:41*am, John Fields wrote:
On Fri, 2 Sep 2011 15:42:28 -0700 (PDT), "

wrote:
On Sep 2, 3:04*pm, John Fields wrote:
On Fri, 2 Sep 2011 05:47:43 -0700 (PDT), "

wrote:
On Aug 30, 6:59*pm, Jeff Liebermann wrote:
On Tue, 30 Aug 2011 10:55:10 -0500, Jeffrey Angus
wrote:

Hasn't anybody read the original question?

Nope. *With 5 groups in the distribution, I just assumed the original
question to not be worth reading. *Besides, some of the groups appear
to be write-only, where nobody (including me) reads the original
question.

That must be the explaination as to why so much crap has been written
on this thread!!

---
The addition of your three turds to this punchbowl certainly isn't
helping, is it?

--
JF

Well they might if you actually read them, I have actually given the
op the correct answer,

---
Really?

Here are your previous posts to this thread:

Your first:

"Finally someone comes up with the correct answer."

Your second:

"Oh they don't do practical here! It's rare for them to get it right
either, this thread is no exception. Some of them even advertise their
place of work! I wonder how much business that has cost them."

Your third:

"That must be the explaination as to why so much crap has been written
on this thread!!"

Which of those gives the correct answer to the OP?

Err the first, maybe you didnt read the post it was replying to.

---

I actually read the question.

---
More's the pity then, since you obviously didn't understand it.

What do you think i didn't understand?

---

Of course your free to ramble on about relays instead of contactors if you like.

---
If you have any capacity for learning, you need to smart up on
reasoning and punctuation before you start talking about **** you know
nothing about.

smarten up John

Just to help you along, here's a clue:

All contactors are relays, but not all relays are contactors.

No there not dopey.

---
Goodbye, inept troll...

PLONK

--
JF- Hide quoted text -

- Show quoted text -

Yes night night, dont forget to take your meds

On Sep 4, 3:25*pm, John Fields wrote:
On Sun, 4 Sep 2011 06:50:56 -0700 (PDT), NT
wrote:



On Sep 4, 11:06*am, John Fields wrote:
On Sat, 3 Sep 2011 17:57:46 -0700 (PDT), NT
wrote:
On Sep 3, 6:50*pm, John Fields wrote:
On Sat, 3 Sep 2011 10:13:51 -0700 (PDT), NT
wrote:
On Sep 2, 8:41*pm, John Fields wrote:
Snipped a lot of repetitious, self serving nonsense.

and if the relay is
designed to operate on AC with a certain RMS current in its coil, how
can it possibly overheat if that current is DC?

With the same current it wont, with higher curren ti will. IIRC you
proposed using 174v rms,

No, I merely added a capacitor across the output of _your_ proposed
full wave rectified 120 VRMS 60Hz source (170V peak) in order to get
smoothed DC closer to the relay's must-make current.

fwliw I said use diodes, you came back with a FW BR. I dont think it
matters.

---
Then show me your circuit.

Just in case you've forgotten, your suggestion was to use a 240V AC
relay using diodes and 120V mains.
---

that would be ok on your specific relay, but
not a universal solution.

???

Your proposd BR+C delivers the right i for one specific relay. For
some relays it will fry them.

---
Show me.

If you want to go get some specs of other relays, you can. This is
starting to get silly.

---
Translation: *"I can do neither, but let me see what I can do to duck
out of here without losing too much face."

translation: if you want to go teach yoursef, youre free to. I'm not
puting however many hours in for you for free.

---
You're the one who made the accusations, copycat, so it's up to you to
prove them.

I havent made any accusations

---
OK, then, unsubstantiated claims.
---

The fact is, you can't, since you have no working circuit which isn't
a full-wave bridge yet uses more than one diode,

what are you talking about

---
You don't know?

By claiming to use "diodes" the meaning is taken that more than one
will be used.

My request was simply to show the circuit.

Can you?
--- *

and there is no relay
with a 240VAC coil which will fry when driven with perfectly rectified
and smoothed 120VAC.

So your sample of one proves it for all relays? Do all have the same L/
R ratio?

---
Unless you can prove my claim is wrong, somehow, my claim stands
undefeated.
---

If you had either you'd post proof but, instead, you choose to be
ignominious.

You get stupid and make personal insults,

---
PKB???
---

AND expect the person you
insult to spend time for you for nothing.

---
I really expect nothing from you, and you may find being called
ignominious insulting, but I was just stating a fact.
---

No, it is not my job, like
everyone here I only write when I have time & feel like it, and its
not my concern whether you look stuff up or not.

---
Well, since it's not my job to do _your_ legwork, and you refuse to
back up what you claim to be true, this discussion is over.

--
JF

what a waste of time

NT wrote:
On Sep 2, 8:41 pm, John Fields wrote:

Snipped a lot of repetitious, self serving nonsense.


and if the relay is
designed to operate on AC with a certain RMS current in its coil, how
can it possibly overheat if that current is DC?

With the same current it wont, with higher curren ti will. IIRC you
proposed using 174v rms,

No, I merely added a capacitor across the output of _your_ proposed
full wave rectified 120 VRMS 60Hz source (170V peak) in order to get
smoothed DC closer to the relay's must-make current.

fwliw I said use diodes, you came back with a FW BR. I dont think it
matters.

---
Then show me your circuit.

Just in case you've forgotten, your suggestion was to use a 240V AC
relay using diodes and 120V mains.
---


that would be ok on your specific relay, but
not a universal solution.

???

Your proposd BR+C delivers the right i for one specific relay. For
some relays it will fry them.

---
Show me.


If you want to go get some specs of other relays, you can. This is
starting to get silly.

Worth investigating, to me. JF gave a specific relay & numbers. I
tried to find a relay to support the idea that an AC/DC relay would
be happy with DC voltage about 50% of AC rating. Can you please
provide a reference?

Meanwhile, what I did find was an ap note from Tyco entitled
"Operating DC Relays from AC and Vice-Versa" .
http://relays.te.com/appnotes/app_pdfs/13c3250.pdf

It does not agree with the DC at ~50% of AC rating idea. It uses
the example of a KR series relay coil. Their example uses a 12
volt AC relay fed by DC. The example states that the "DC voltage
cannot exceed 9.8 volts", and "should not be lower than 7.35 volts".
Thus the DC range would be ~61%(minimum) to ~81% (maximum) of the
12VAC rating.

Extrapolating, it does agree with the idea of BR+C fed by 120 for
the 240 volt relay, insofar as the DC voltage:
~146VDC min to ~194VDC max, which makes the midpoint ~170VDC.
That's very close to ~168 from the BR+C

Regarding coil ratings, I've worked with DC relays, and I've worked
with AC relays, but I haven't worked with AC/DC coil relays, so
I can't speak from experience with them, and I haven't found
anything yet specifically dealing with that, other than the
link I found to Tyco. So a specific link or links would be
most helpful.

Thanks,
Ed

ehsjr wrote:
NT wrote:

On Sep 2, 8:41 pm, John Fields wrote:

Snipped a lot of repetitious, self serving nonsense.


and if the relay is
designed to operate on AC with a certain RMS current in its coil,
how
can it possibly overheat if that current is DC?


With the same current it wont, with higher curren ti will. IIRC you
proposed using 174v rms,


No, I merely added a capacitor across the output of _your_ proposed
full wave rectified 120 VRMS 60Hz source (170V peak) in order to get
smoothed DC closer to the relay's must-make current.


fwliw I said use diodes, you came back with a FW BR. I dont think it
matters.


---
Then show me your circuit.

Just in case you've forgotten, your suggestion was to use a 240V AC
relay using diodes and 120V mains.
---


that would be ok on your specific relay, but
not a universal solution.


???


Your proposd BR+C delivers the right i for one specific relay. For
some relays it will fry them.


---
Show me.



If you want to go get some specs of other relays, you can. This is
starting to get silly.


Worth investigating, to me. JF gave a specific relay & numbers. I
tried to find a relay to support the idea that an AC/DC relay would
be happy with DC voltage about 50% of AC rating. Can you please
provide a reference?

Meanwhile, what I did find was an ap note from Tyco entitled
"Operating DC Relays from AC and Vice-Versa" .
http://relays.te.com/appnotes/app_pdfs/13c3250.pdf

It does not agree with the DC at ~50% of AC rating idea. It uses
the example of a KR series relay coil. Their example uses a 12
volt AC relay fed by DC. The example states that the "DC voltage
cannot exceed 9.8 volts", and "should not be lower than 7.35 volts".
Thus the DC range would be ~61%(minimum) to ~81% (maximum) of the
12VAC rating.

Extrapolating, it does agree with the idea of BR+C fed by 120 for
the 240 volt relay, insofar as the DC voltage:
~146VDC min to ~194VDC max, which makes the midpoint ~170VDC.
That's very close to ~168 from the BR+C

Regarding coil ratings, I've worked with DC relays, and I've worked
with AC relays, but I haven't worked with AC/DC coil relays, so
I can't speak from experience with them, and I haven't found
anything yet specifically dealing with that, other than the
link I found to Tyco. So a specific link or links would be
most helpful.

Thanks,
Ed
You must remember that AC coil relays are wound a little different,
its not just induction here. Inter pole windings help keep the AC coil
from chattering the armature. I am sure under DC operation, this may
effect the calculations.

There are some AC coil relays that do not do this and thus the 50%
voltage for DC should come close, but then again, DC R in the coil also
plays a role in this.

Jamie

Jamie wrote:
ehsjr wrote:

NT wrote:

On Sep 2, 8:41 pm, John Fields wrote:

Snipped a lot of repetitious, self serving nonsense.


and if the relay is
designed to operate on AC with a certain RMS current in its
coil, how
can it possibly overheat if that current is DC?



With the same current it wont, with higher curren ti will. IIRC you
proposed using 174v rms,



No, I merely added a capacitor across the output of _your_ proposed
full wave rectified 120 VRMS 60Hz source (170V peak) in order to get
smoothed DC closer to the relay's must-make current.



fwliw I said use diodes, you came back with a FW BR. I dont think it
matters.



---
Then show me your circuit.

Just in case you've forgotten, your suggestion was to use a 240V AC
relay using diodes and 120V mains.
---


that would be ok on your specific relay, but
not a universal solution.



???



Your proposd BR+C delivers the right i for one specific relay. For
some relays it will fry them.



---
Show me.




If you want to go get some specs of other relays, you can. This is
starting to get silly.



Worth investigating, to me. JF gave a specific relay & numbers. I
tried to find a relay to support the idea that an AC/DC relay would
be happy with DC voltage about 50% of AC rating. Can you please
provide a reference?

Meanwhile, what I did find was an ap note from Tyco entitled
"Operating DC Relays from AC and Vice-Versa" .
http://relays.te.com/appnotes/app_pdfs/13c3250.pdf

It does not agree with the DC at ~50% of AC rating idea. It uses
the example of a KR series relay coil. Their example uses a 12
volt AC relay fed by DC. The example states that the "DC voltage
cannot exceed 9.8 volts", and "should not be lower than 7.35 volts".
Thus the DC range would be ~61%(minimum) to ~81% (maximum) of the
12VAC rating.

Extrapolating, it does agree with the idea of BR+C fed by 120 for
the 240 volt relay, insofar as the DC voltage:
~146VDC min to ~194VDC max, which makes the midpoint ~170VDC.
That's very close to ~168 from the BR+C

Regarding coil ratings, I've worked with DC relays, and I've worked
with AC relays, but I haven't worked with AC/DC coil relays, so
I can't speak from experience with them, and I haven't found
anything yet specifically dealing with that, other than the
link I found to Tyco. So a specific link or links would be
most helpful.

Thanks,
Ed

You must remember that AC coil relays are wound a little different,
its not just induction here. Inter pole windings help keep the AC coil
from chattering the armature. I am sure under DC operation, this may
effect the calculations.

There are some AC coil relays that do not do this and thus the 50%
voltage for DC should come close, but then again, DC R in the coil also
plays a role in this.

Jamie


Your post contains nothing specific and does not address
my question.

I am looking for a specific link or links that shows a datasheet,
ap note, or example of a relay that NT has in mind. Do you have one?

I want specifics, like John Fields posted; the specs that NT
said you could get: "If you want to go get some specs of other
relays, you can." The specs I have been able to find so far
do not demonstrate what NT was talking about, thus my post
asking for a reference.

Ed

ehsjr wrote:
Jamie wrote:

ehsjr wrote:

NT wrote:

On Sep 2, 8:41 pm, John Fields wrote:

Snipped a lot of repetitious, self serving nonsense.


and if the relay is
designed to operate on AC with a certain RMS current in its
coil, how
can it possibly overheat if that current is DC?




With the same current it wont, with higher curren ti will. IIRC you
proposed using 174v rms,




No, I merely added a capacitor across the output of _your_ proposed
full wave rectified 120 VRMS 60Hz source (170V peak) in order to get
smoothed DC closer to the relay's must-make current.




fwliw I said use diodes, you came back with a FW BR. I dont think it
matters.




---
Then show me your circuit.

Just in case you've forgotten, your suggestion was to use a 240V AC
relay using diodes and 120V mains.
---


that would be ok on your specific relay, but
not a universal solution.




???




Your proposd BR+C delivers the right i for one specific relay. For
some relays it will fry them.




---
Show me.





If you want to go get some specs of other relays, you can. This is
starting to get silly.




Worth investigating, to me. JF gave a specific relay & numbers. I
tried to find a relay to support the idea that an AC/DC relay would
be happy with DC voltage about 50% of AC rating. Can you please
provide a reference?

Meanwhile, what I did find was an ap note from Tyco entitled
"Operating DC Relays from AC and Vice-Versa" .
http://relays.te.com/appnotes/app_pdfs/13c3250.pdf

It does not agree with the DC at ~50% of AC rating idea. It uses
the example of a KR series relay coil. Their example uses a 12
volt AC relay fed by DC. The example states that the "DC voltage
cannot exceed 9.8 volts", and "should not be lower than 7.35 volts".
Thus the DC range would be ~61%(minimum) to ~81% (maximum) of the
12VAC rating.

Extrapolating, it does agree with the idea of BR+C fed by 120 for
the 240 volt relay, insofar as the DC voltage:
~146VDC min to ~194VDC max, which makes the midpoint ~170VDC.
That's very close to ~168 from the BR+C

Regarding coil ratings, I've worked with DC relays, and I've worked
with AC relays, but I haven't worked with AC/DC coil relays, so
I can't speak from experience with them, and I haven't found
anything yet specifically dealing with that, other than the
link I found to Tyco. So a specific link or links would be
most helpful.

Thanks,
Ed


You must remember that AC coil relays are wound a little different,
its not just induction here. Inter pole windings help keep the AC coil
from chattering the armature. I am sure under DC operation, this may
effect the calculations.

There are some AC coil relays that do not do this and thus the 50%
voltage for DC should come close, but then again, DC R in the coil also
plays a role in this.

Jamie


Your post contains nothing specific and does not address
my question.

I am looking for a specific link or links that shows a datasheet,
ap note, or example of a relay that NT has in mind. Do you have one?

I want specifics, like John Fields posted; the specs that NT
said you could get: "If you want to go get some specs of other
relays, you can." The specs I have been able to find so far
do not demonstrate what NT was talking about, thus my post
asking for a reference.

Ed
Don't be anal, they make relays that will do AD/DC because they have a
diode imbedded in them. The voltage ratings are the same. The coil is
actually of DC type.. They also have relays with shunt diodes built into
them, for those you need to insure the polarity is correct and are
strictly DC only.

We also deal with solenoids to operate in the same manner..

Scroll down and read about AC coils, I am sure if you're looking for
some more detailed information you can find it, but this will explain
some of the differences.

http://www.ehow.com/about_6498402_di...elay-coil.html


Jamie

On Sep 8, 11:23*am, Jamie
t wrote:
ehsjr wrote:
Jamie wrote:

ehsjr wrote:

NT wrote:

On Sep 2, 8:41 pm, John Fields wrote:

Snipped a lot of repetitious, self serving nonsense.

and if the relay is
designed to operate on AC with a certain RMS current in its
coil, how
can it possibly overheat if that current is DC?

With the same current it wont, with higher curren ti will. IIRC you
proposed using 174v rms,

No, I merely added a capacitor across the output of _your_ proposed
full wave rectified 120 VRMS 60Hz source (170V peak) in order to get
smoothed DC closer to the relay's must-make current.

fwliw I said use diodes, you came back with a FW BR. I dont think it
matters.

---
Then show me your circuit.

Just in case you've forgotten, your suggestion was to use a 240V AC
relay using diodes and 120V mains.
---

that would be ok on your specific relay, but
not a universal solution.

???

Your proposd BR+C delivers the right i for one specific relay. For
some relays it will fry them.

---
Show me.

If you want to go get some specs of other relays, you can. This is
starting to get silly.

Worth investigating, to me. JF gave a specific relay & numbers. *I
tried to find a relay to support the idea that an AC/DC relay would
be happy with DC voltage about 50% of AC rating. *Can you please
provide a reference?

Meanwhile, what I did find was an ap note from Tyco entitled
"Operating DC Relays from AC and Vice-Versa" .
http://relays.te.com/appnotes/app_pdfs/13c3250.pdf

It does not agree with the DC at ~50% of AC rating idea. It uses
the example of a KR series relay coil. Their example uses a 12
volt AC relay fed by DC. *The example states that the "DC voltage
cannot exceed 9.8 volts", and "should not be lower than 7.35 volts".
Thus the DC range would be ~61%(minimum) to ~81% (maximum) of the
12VAC rating.

Extrapolating, it does agree with the idea of BR+C fed by 120 for
the 240 volt relay, insofar as the DC voltage:
~146VDC min to ~194VDC max, which makes the midpoint ~170VDC.
That's very close to ~168 from the BR+C

Regarding coil ratings, I've worked with DC relays, and I've worked
with AC relays, but I haven't worked with AC/DC coil relays, so
I can't speak from experience with them, and I haven't found
anything yet specifically dealing with that, other than the
link I found to Tyco. *So a specific link or links would be
most helpful.

Thanks,
Ed

* You must remember that AC coil relays are wound a little different,
its not just induction here. Inter pole windings help keep the AC coil
from chattering the armature. I am sure under DC operation, this may
effect the calculations.

* There are some AC coil relays that do not do this and thus the 50%
voltage for DC should come close, but then again, DC R in the coil also
*plays a role in this.

*Jamie

Your post contains nothing specific and does not address
my question.

I am looking for a specific link or links that shows a datasheet,
ap note, or example of a relay that NT has in mind. Do you have one?

I want specifics, like John Fields posted; the specs that NT
said you could get: "If you want to go get some specs of other
relays, you can." *The specs I have been able to find so far
do not demonstrate what NT was talking about, thus my post
asking for a reference.

Ed

Don't be anal, they make relays that will do AD/DC because they have a
diode imbedded in them. The voltage ratings are the same. The coil is
actually of DC type.. They also have relays with shunt diodes built into
them, for those you need to insure the polarity is correct and are
strictly DC only.

* *We also deal with solenoids to operate in the same manner..

Scroll down and read about AC coils, I am sure if you're looking for
some more detailed information you can find it, but this will explain
some of the differences.

http://www.ehow.com/about_6498402_di...elay-coil.html

Jamie

First you tell him not to be anal then you lube him up really good
then you ram your howdy doody linkage , what's up kiddo?
BOOWAHAHA...I JUST HAD TO, YOU HAD TO LOL
MOST UNIVERSAL MODELS ARE SOMEWHAT ERRATIC & DUBIOUS.
EUROS AND AMERICANS WILL ALWAYS BE THEMSELVES, BEST CAN BE DONE IS PUT
TO USE A CONVERTER DEVICE HARMONIC WITH BOTH WAVES PHI's. OR FREQUENCY
TO OR FROM THE INSTINCTIVE DEVICE BE IT AC OR DC PLAIN COIL OR
CONTACTOR WHICH IS HIS CONUNDRUM.

PLEASE SEND YOUR ARGUMENTS TO WHO GIVES A FLYING ****.COM :-)

TGITM

The Ghost In The Machine wrote:

On Sep 8, 11:23 am, Jamie
t wrote:

ehsjr wrote:

Jamie wrote:

ehsjr wrote:

NT wrote:

On Sep 2, 8:41 pm, John Fields wrote:

Snipped a lot of repetitious, self serving nonsense.

and if the relay is
designed to operate on AC with a certain RMS current in its
coil, how
can it possibly overheat if that current is DC?

With the same current it wont, with higher curren ti will. IIRC you
proposed using 174v rms,

No, I merely added a capacitor across the output of _your_ proposed
full wave rectified 120 VRMS 60Hz source (170V peak) in order to get
smoothed DC closer to the relay's must-make current.

fwliw I said use diodes, you came back with a FW BR. I dont think it
matters.

---
Then show me your circuit.

Just in case you've forgotten, your suggestion was to use a 240V AC
relay using diodes and 120V mains.
---

that would be ok on your specific relay, but
not a universal solution.

???

Your proposd BR+C delivers the right i for one specific relay. For
some relays it will fry them.

---
Show me.

If you want to go get some specs of other relays, you can. This is
starting to get silly.

Worth investigating, to me. JF gave a specific relay & numbers. I
tried to find a relay to support the idea that an AC/DC relay would
be happy with DC voltage about 50% of AC rating. Can you please
provide a reference?

Meanwhile, what I did find was an ap note from Tyco entitled
"Operating DC Relays from AC and Vice-Versa" .
http://relays.te.com/appnotes/app_pdfs/13c3250.pdf

It does not agree with the DC at ~50% of AC rating idea. It uses
the example of a KR series relay coil. Their example uses a 12
volt AC relay fed by DC. The example states that the "DC voltage
cannot exceed 9.8 volts", and "should not be lower than 7.35 volts".
Thus the DC range would be ~61%(minimum) to ~81% (maximum) of the
12VAC rating.

Extrapolating, it does agree with the idea of BR+C fed by 120 for
the 240 volt relay, insofar as the DC voltage:
~146VDC min to ~194VDC max, which makes the midpoint ~170VDC.
That's very close to ~168 from the BR+C

Regarding coil ratings, I've worked with DC relays, and I've worked
with AC relays, but I haven't worked with AC/DC coil relays, so
I can't speak from experience with them, and I haven't found
anything yet specifically dealing with that, other than the
link I found to Tyco. So a specific link or links would be
most helpful.

Thanks,
Ed

You must remember that AC coil relays are wound a little different,
its not just induction here. Inter pole windings help keep the AC coil
from chattering the armature. I am sure under DC operation, this may
effect the calculations.

There are some AC coil relays that do not do this and thus the 50%
voltage for DC should come close, but then again, DC R in the coil also
plays a role in this.

Jamie

Your post contains nothing specific and does not address
my question.

I am looking for a specific link or links that shows a datasheet,
ap note, or example of a relay that NT has in mind. Do you have one?

I want specifics, like John Fields posted; the specs that NT
said you could get: "If you want to go get some specs of other
relays, you can." The specs I have been able to find so far
do not demonstrate what NT was talking about, thus my post
asking for a reference.

Ed

Don't be anal, they make relays that will do AD/DC because they have a
diode imbedded in them. The voltage ratings are the same. The coil is
actually of DC type.. They also have relays with shunt diodes built into
them, for those you need to insure the polarity is correct and are
strictly DC only.

We also deal with solenoids to operate in the same manner..

Scroll down and read about AC coils, I am sure if you're looking for
some more detailed information you can find it, but this will explain
some of the differences.

http://www.ehow.com/about_6498402_di...elay-coil.html

Jamie


First you tell him not to be anal then you lube him up really good
then you ram your howdy doody linkage , what's up kiddo?
BOOWAHAHA...I JUST HAD TO, YOU HAD TO LOL
MOST UNIVERSAL MODELS ARE SOMEWHAT ERRATIC & DUBIOUS.
EUROS AND AMERICANS WILL ALWAYS BE THEMSELVES, BEST CAN BE DONE IS PUT
TO USE A CONVERTER DEVICE HARMONIC WITH BOTH WAVES PHI's. OR FREQUENCY
TO OR FROM THE INSTINCTIVE DEVICE BE IT AC OR DC PLAIN COIL OR
CONTACTOR WHICH IS HIS CONUNDRUM.

PLEASE SEND YOUR ARGUMENTS TO WHO GIVES A FLYING ****.COM :-)

TGITM
You must? You read and replied to it. It didn't concern you one bit how
ever, you were interested enough to push those fat fingers along while
burning all those calories sitting on your fat ass, just to post your
dumb ****..


You are taking up valuable space, move on and allow some one more
deserving to fill that gap.

Jamie

On Sep 8, 2:30*pm, Jamie
t wrote:
The Ghost In The Machine wrote:





On Sep 8, 11:23 am, Jamie
t wrote:

ehsjr wrote:

Jamie wrote:

ehsjr wrote:

NT wrote:

On Sep 2, 8:41 pm, John Fields wrote:

Snipped a lot of repetitious, self serving nonsense.

and if the relay is
designed to operate on AC with a certain RMS current in its
coil, how
can it possibly overheat if that current is DC?

With the same current it wont, with higher curren ti will. IIRC you
proposed using 174v rms,

No, I merely added a capacitor across the output of _your_ proposed
full wave rectified 120 VRMS 60Hz source (170V peak) in order to get
smoothed DC closer to the relay's must-make current.

fwliw I said use diodes, you came back with a FW BR. I dont think it
matters.

---
Then show me your circuit.

Just in case you've forgotten, your suggestion was to use a 240V AC
relay using diodes and 120V mains.
---

that would be ok on your specific relay, but
not a universal solution.

???

Your proposd BR+C delivers the right i for one specific relay. For
some relays it will fry them.

---
Show me.

If you want to go get some specs of other relays, you can. This is
starting to get silly.

Worth investigating, to me. JF gave a specific relay & numbers. *I
tried to find a relay to support the idea that an AC/DC relay would
be happy with DC voltage about 50% of AC rating. *Can you please
provide a reference?

Meanwhile, what I did find was an ap note from Tyco entitled
"Operating DC Relays from AC and Vice-Versa" .
http://relays.te.com/appnotes/app_pdfs/13c3250.pdf

It does not agree with the DC at ~50% of AC rating idea. It uses
the example of a KR series relay coil. Their example uses a 12
volt AC relay fed by DC. *The example states that the "DC voltage
cannot exceed 9.8 volts", and "should not be lower than 7.35 volts".
Thus the DC range would be ~61%(minimum) to ~81% (maximum) of the
12VAC rating.

Extrapolating, it does agree with the idea of BR+C fed by 120 for
the 240 volt relay, insofar as the DC voltage:
~146VDC min to ~194VDC max, which makes the midpoint ~170VDC.
That's very close to ~168 from the BR+C

Regarding coil ratings, I've worked with DC relays, and I've worked
with AC relays, but I haven't worked with AC/DC coil relays, so
I can't speak from experience with them, and I haven't found
anything yet specifically dealing with that, other than the
link I found to Tyco. *So a specific link or links would be
most helpful.

Thanks,
Ed

*You must remember that AC coil relays are wound a little different,
its not just induction here. Inter pole windings help keep the AC coil
from chattering the armature. I am sure under DC operation, this may
effect the calculations.

*There are some AC coil relays that do not do this and thus the 50%
voltage for DC should come close, but then again, DC R in the coil also
plays a role in this.

Jamie

Your post contains nothing specific and does not address
my question.

I am looking for a specific link or links that shows a datasheet,
ap note, or example of a relay that NT has in mind. Do you have one?

I want specifics, like John Fields posted; the specs that NT
said you could get: "If you want to go get some specs of other
relays, you can." *The specs I have been able to find so far
do not demonstrate what NT was talking about, thus my post
asking for a reference.

Ed

Don't be anal, they make relays that will do AD/DC because they have a
diode imbedded in them. The voltage ratings are the same. The coil is
actually of DC type.. They also have relays with shunt diodes built into
them, for those you need to insure the polarity is correct and are
strictly DC only.

* We also deal with solenoids to operate in the same manner..

Scroll down and read about AC coils, I am sure if you're looking for
some more detailed information you can find it, but this will explain
some of the differences.

http://www.ehow.com/about_6498402_di...elay-coil.html

Jamie

First you tell him not to be anal then you lube him up really good
then you ram your howdy doody linkage , what's up kiddo?
BOOWAHAHA...I JUST HAD TO, YOU HAD TO LOL
MOST UNIVERSAL MODELS ARE SOMEWHAT ERRATIC & DUBIOUS.
EUROS AND AMERICANS WILL ALWAYS BE THEMSELVES, BEST CAN BE DONE IS PUT
TO USE A CONVERTER DEVICE HARMONIC WITH BOTH WAVES PHI's. OR FREQUENCY
TO OR FROM THE INSTINCTIVE DEVICE BE IT AC OR DC *PLAIN COIL OR
CONTACTOR WHICH IS HIS CONUNDRUM.

PLEASE SEND YOUR ARGUMENTS TO WHO GIVES A FLYING ****.COM :-)

TGITM

You must? You read and replied to it. It didn't concern you one bit how
ever, you were interested enough to push those fat fingers along while
burning all those calories sitting on your fat ass, just to post your
dumb ****..

* *You are taking up valuable space, move on and allow some one more
deserving to fill that gap.

Jamie

YOU THINK YOU KNOW SOMEONE MORE DESERVING?
**** YOU CUMSHOT..GO POP YOUR LOAD SOMEWHERE ELSE.
TELL YOUR FAT ASS FATHER I AM POSTING HIS NAME AS A REFERNCE ON A
HAUNTED HOUSE I HAVE MY EYES ON......BOOWAHAHAHAHA!
AND DONT ASK ME TO BILL THE GROUP FOR MY SERVICES EITHER.
THIS IS HOW WE DO IT.
PATECUM
TGITM