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Default Re-winding solenoids.

On Oct 19, 6:59*pm, Jamie
t wrote:
spamtrap1888 wrote:
On Oct 19, 3:14 pm, Jamie
t wrote:


spamtrap1888 wrote:


On Oct 19, 5:09 am, Jeffrey Angus wrote:


On 10/17/2011 6:05 PM, Jamie wrote:


You know, at this point, you pretty much don't care


You're right. I don't. Because my original question was
in regards to ampere turns and rewinding a solenoid for
a different operating voltage.


I wish that that had been your original question, which was a rambling
stream of consciousness. Your reference to a program for calculating
aircore inductors made me think you were using "solenoid" in the sense
of "helical coil."


Because so far, with one notable exception, everyone has
insisted on coming up with some Rube Goldberg solution or
accusing me of trying to murder widows and orphans.


Your desire to save $380 in the belief that ASCO was screwing its
customers with jacked-up prices seemed a bit unreasonable, the more so
when you revealed the true application for the solenoid actuator.


But your juryrig would merely produce widows and orphans, not kill
them. Only the lineman trying to restore power would be killed if your
Rube Goldberg solution failed to work.


I must say, you are an idiot!


*How is the device itself any less dangerous than using an alternate to
operate it?


Jamie


If the alternate does not operate sufficiently like the original.


If he could explain how the actuator works and what the important
parameters were, we could speculate as to all the possible failure
modes.


You can speculate all you want. You sound like an attorney looking for
work or closely related to one.

* *If you read the blog, you would see what he is using if for, and if
he really wants you to know, I am sure he'll refresh your memory.


I used to break things for a living. Before that, I had to worry about
the adequacy of insulation. From his first post, the guy did not
appear to understand much of anything. I hoped he at least would not
kill anyone.

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Default Re-winding solenoids.

On 10/19/2011 9:38 PM, spamtrap1888 wrote:
From his first post, the guy did not appear to understand
much of anything. I hoped he at least would not kill anyone.


Really? Explain how you came to that conclusion.

I started with known measured numbers. Worked backwards with
a calculator to get the unknown. From there I went forward
towards what I thought was correct.

Then asked if what I was doing sounded right. I.e. basing the
requirements on ampere turns.

I even went so far as to include the calculator I used to
determine the number turns based on the physical size, DC
resistance and measured inductance.

So, and unfortunately VERY typical of Usenet, I've had to put
up with unfounded personal attacks and a whole plethora of
"How you should do anything except what you want to."

Jeff-1.0

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Default Re-winding solenoids.

On Oct 16, 4:48*pm, Jeffrey Angus wrote:
Just a few abstract thoughts here. It makes sense to me,
but then I've been known to over look the obvious on
occasion. ;-)

I have a solenoid coil that actuates a large 3-pole
contactor. A short pulse to pull up on a lever that
will toggle it from on position to another, and back.

Making measurements of the solenoid coil, although
potted in epoxy, yields a few measurements and a
couple of guesses.

http://www.pronine.ca/multind.htm

Coil form 1" diameter, 1-3/8" width and 1.5" depth.
Going backwards on a solenoid coil java script, yields
a matching 125 mH inductance (as measured) and 95 ohm
DCR (as measured) for 2500 turns of #30 AWG which will
fill the bobbin.

This a 480 VAC actuator.

Am I headed in the right direction if I assume the key
factor here is ampere turns?

Not allowing for the added inductance by a movable core,
this has an impedance of roughly 100 ohms. So that works
out to 4.8 amps or 12,000 ampere turns.

Substituting 2000 turns of #28 AWG yields 80 mH, and 42
Ohms. And subsequently roughly 12,000 ampere turns at
240 VAC.

Putting 240 VAC across the 480 VAC coil yields only 6,000
ampere turns and obviously is NOT enough to actuate the
contactor transfer mechanism.

The reason I'm curious is that ASCO seems to think that
the replacement coil for this is worth $585, although
they will sell it as the "sale price" of only $421.80.

Jeff-1.0
The other other one

--
"Everything from Crackers to Coffins"


Hi Jeff, I know nothing about power stuff or soleniod coils. I have
made a few open air magnetics. (Usually Helmholtz things) If the size
of both air coils is the same, then I believe your calculations are
correct. It's only the magnetic field strength that you need to match
and that's proportional to number of amp-turns. Wind away I say!

George H.
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Default Re-winding solenoids.

On Oct 20, 4:31*pm, George Herold wrote:
On Oct 16, 4:48*pm, Jeffrey Angus wrote:





Just a few abstract thoughts here. It makes sense to me,
but then I've been known to over look the obvious on
occasion. ;-)


I have a solenoid coil that actuates a large 3-pole
contactor. A short pulse to pull up on a lever that
will toggle it from on position to another, and back.


Making measurements of the solenoid coil, although
potted in epoxy, yields a few measurements and a
couple of guesses.


http://www.pronine.ca/multind.htm


Coil form 1" diameter, 1-3/8" width and 1.5" depth.
Going backwards on a solenoid coil java script, yields
a matching 125 mH inductance (as measured) and 95 ohm
DCR (as measured) for 2500 turns of #30 AWG which will
fill the bobbin.


This a 480 VAC actuator.


Am I headed in the right direction if I assume the key
factor here is ampere turns?


Not allowing for the added inductance by a movable core,
this has an impedance of roughly 100 ohms. So that works
out to 4.8 amps or 12,000 ampere turns.


Substituting 2000 turns of #28 AWG yields 80 mH, and 42
Ohms. And subsequently roughly 12,000 ampere turns at
240 VAC.


Putting 240 VAC across the 480 VAC coil yields only 6,000
ampere turns and obviously is NOT enough to actuate the
contactor transfer mechanism.


The reason I'm curious is that ASCO seems to think that
the replacement coil for this is worth $585, although
they will sell it as the "sale price" of only $421.80.


Jeff-1.0
The other other one


--
"Everything from Crackers to Coffins"


Hi Jeff, *I know nothing about power stuff or soleniod coils. *I have
made a few open air magnetics. (Usually Helmholtz things) If the size
of both air coils is the same, then I believe your calculations are
correct. *It's only the magnetic field strength that you need to match
and that's proportional to number of amp-turns. *Wind away I say!


Driving home, I was thinking that since you're doing a pulsed thing
you may care about the L/R time constant. (Is the pulse time much
longer than that?) Did 'your' program spit out inductance values
too? (Forgive me, I'm too lazy to look for them.) For 'thin' coils
you'd expect the inducatance (for the low voltage coil) to go down by
four and the resistance to go down by two, so a decrease of two in the
time constant... hardly seems like it would matter, unless somethng
else in the circuit is expectng it to take longer. For your fat coil
the change in time constant is likely even less.

George H.



George H.- Hide quoted text -

- Show quoted text -


Oh
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Default Re-winding solenoids.

On 10/20/2011 5:54 PM, George Herold wrote:
Driving home, I was thinking that since you're doing a pulsed thing
you may care about the L/R time constant. (Is the pulse time much
longer than that?)


The pulse is mechanically derived.
The small control relay energizes the solenoid. When the solenoid
causes the transfer switch to actuate, the auxiliary contacts
open the solenoid connection.

Jeff-1.0

--
"Everything from Crackers to Coffins"


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Default Re-winding solenoids.

On Wed, 19 Oct 2011 21:32:14 -0500, Jeffrey Angus
wrote:

On 10/19/2011 8:39 PM, spamtrap1888 wrote:
I see that only the ASCO 4000 and 7000 series are closed-transition
switches, i.e. break before make, not the Series 940 -- which I had to
look up from the replacement part number you gave.

My bad, I suppose.


I suppose. The solenoid coil listed is for the series 940. It
is also used for several other series. Specifically, in my case,
the Series 386 manual transfer switch.

And in case you missed it earlier, here is the link for an eBay
auction showing picturs of the transfer switch contactor.

A similar model. 2-pole 120 VAC rather than 3-pole 480 VAC.
http://www.ebay.com/itm/130520617745

And if you go to the partsasco.com website and look up the replacement
part numbers for the model 300 or 386, it directs you to the coil
marked as being for the series 940.

This is the coil itself from ASCO.
http://www.ascoparts.com/343500-063.html

But again, you're making all sorts of asumption looking to find
fault. You've done nothing what so ever to answer the question
on rewinding a solenoid to operate at 240 volts rather than 480.

Jeff-1.0


Just for grins, Jeff 1.0 have you tried spice models of the rectifier
solenoid at 480 and 240? It may help you see something you may have
missed. BTW i expect you will replace the bridge with one appropriated
rated for the solenoid?

?-)
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Default Re-winding solenoids.

On 10/20/2011 9:51 PM, josephkk wrote:
Just for grins, Jeff 1.0 have you tried spice models of the rectifier
solenoid at 480 and 240? It may help you see something you may have
missed.


It hadn't occurred to me to do that. It's pretty much of a static
operation. You apply power, it pulls up on the armature. When the
mechanism changes position, an auxiliary switch disconnects the
solenoid.

BTW i expect you will replace the bridge with one appropriated
rated for the solenoid?


The original bridge was dealing with 480 vac @ 5.2 amps. The new
coil will present a load of about 4 amps @ 240 vac. It's not an
issue.

Jeff-1.0



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Default Re-winding solenoids.

On Fri, 21 Oct 2011 05:22:39 -0500, Jeffrey Angus
wrote:

On 10/20/2011 9:51 PM, josephkk wrote:
Just for grins, Jeff 1.0 have you tried spice models of the rectifier
solenoid at 480 and 240? It may help you see something you may have
missed.


It hadn't occurred to me to do that.


See
where I mumbled:
At 60Hz, that's 276 uF. 330uf 600VDC caps should work.
I'm not very confident with my crude approximations. Therefore,
I would feed the model to LTSpice and see what it's really going
to do.
http://www.linear.com/designtools/software/#LTspice
Look for current and voltage spikes.

It's pretty much of a static
operation. You apply power, it pulls up on the armature. When the
mechanism changes position, an auxiliary switch disconnects the
solenoid.


You can specify an input pulse with:

Syntax: Ixxx n+ n- PULSE(Ioff Ion Tdelay Trise Tfall Ton Tperiod
Ncycles)

There are also other circuit simulators that might work:
http://www.falstad.com/circuit/ (Java)

Make me rich and I'll do the recti-fire and sol-e-void model for you.


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# 831-336-2558
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Default Re-winding solenoids.

On Fri, 21 Oct 2011 05:22:39 -0500, Jeffrey Angus
wrote:

On 10/20/2011 9:51 PM, josephkk wrote:
Just for grins, Jeff 1.0 have you tried spice models of the rectifier
solenoid at 480 and 240? It may help you see something you may have
missed.


It hadn't occurred to me to do that. It's pretty much of a static
operation. You apply power, it pulls up on the armature. When the
mechanism changes position, an auxiliary switch disconnects the
solenoid.


I expect you can learn interesting things looking at the current waveforms
in the various configurations.


BTW i expect you will replace the bridge with one appropriated
rated for the solenoid?


The original bridge was dealing with 480 vac @ 5.2 amps. The new
coil will present a load of about 4 amps @ 240 vac. It's not an
issue.


That does not make sense for the ampere-turns argument. The number of
turns drops dramatically thus the current must increase accordingly.


Jeff-1.0

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On 10/22/2011 11:55 PM, josephkk wrote:

The original bridge was dealing with 480 vac @ 5.2 amps. The new
coil will present a load of about 4 amps @ 240 vac. It's not an
issue.

That does not make sense for the ampere-turns argument. The number of
turns drops dramatically thus the current must increase accordingly.


480v coil 2500 turns @ 4.8 amps
240 coil 2000 turns @ 6.0 amps

Jeff-1.0


--
"Everything from Crackers to Coffins"


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On Sun, 23 Oct 2011 03:36:07 -0500, Jeffrey Angus
wrote:

On 10/22/2011 11:55 PM, josephkk wrote:

The original bridge was dealing with 480 vac @ 5.2 amps. The new
coil will present a load of about 4 amps @ 240 vac. It's not an
issue.

That does not make sense for the ampere-turns argument. The number of
turns drops dramatically thus the current must increase accordingly.


480v coil 2500 turns @ 4.8 amps
240 coil 2000 turns @ 6.0 amps

Jeff-1.0


Not as bad of a turns drop as thought. The new numbers make sense.

?-)
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Default Re-winding solenoids.

A follow up to this exercise.

Using 1/16" PVC for the ends and schedule 40 1/2" PVC
for the core, I wound 2000 turns of #28 wire on the
form and put things together to test them.

It works with 240 VAC across the bridge rectifier now.

And yes, the coil heats up. It's trying to dissipate
1440 watts. (240 VAC @ 6 amps)

The contacts on the transfer switch disconnect the
solenoid coil from power as soon as it starts to move.
Inertia carries it through the sequence.

Jeff-1.0

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On Sun, 13 Nov 2011 15:08:29 -0600, Jeffrey Angus
wrote:

And yes, the coil heats up. It's trying to dissipate
1440 watts. (240 VAC @ 6 amps)


You might want to add a thermal fuse in series with the coil. It the
contactor gets stuck in the energized position, you might have a fire.

The contacts on the transfer switch disconnect the
solenoid coil from power as soon as it starts to move.
Inertia carries it through the sequence.


That happens it the actuator gets stuck or if the energizing voltage
is unusually low? Duz it stick in the "on" state?

Worrying about the widows and orphans this might harm...



--
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150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
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On 11/13/2011 6:19 PM, Jeff Liebermann wrote:
On Sun, 13 Nov 2011 15:08:29 -0600, Jeffrey
wrote:

And yes, the coil heats up. It's trying to dissipate
1440 watts. (240 VAC @ 6 amps)

You might want to add a thermal fuse in series with the coil. It the
contactor gets stuck in the energized position, you might have a fire.


There is that. See below...

The contacts on the transfer switch disconnect the
solenoid coil from power as soon as it starts to move.
Inertia carries it through the sequence.

That happens it the actuator gets stuck or if the energizing voltage
is unusually low? Duz it stick in the "on" state?

Worrying about the widows and orphans this might harm...


See, now this is where everyone got upset over nothing.

This whole exercise was to see _IF_ I could correctly wind a
replacement solenoid for 240 V rather than the original 480 V.

Now that I've satisfied my curiosity, I'm going to sell it in
it's original format (480 v 3-phase) as THAT is where it's value
lies.

Jeff

--
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On Sun, 13 Nov 2011 20:47:45 -0600, Jeffrey Angus
wrote:

This whole exercise was to see _IF_ I could correctly wind a
replacement solenoid for 240 V rather than the original 480 V.

Now that I've satisfied my curiosity, I'm going to sell it in
it's original format (480 v 3-phase) as THAT is where it's value
lies.


So, this was all an academic exercise, with no practical purpose or
monetary value? Had I known, I would have been less helpful and more
insulting. You should feel guilty for having wasted my time. For
penitence, please either flog yourself, or send me an appropriate
percentage of the proceeds.

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


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On 11/13/2011 10:43 PM, Jeff Liebermann wrote:
send me an appropriate percentage of the proceeds.


Fear not fearless leader, I'll remember to cut you in.

Jeff-1.0


--
"Everything from Crackers to Coffins"
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