Pics with the VFD mounted, and all up and running. I actually produced some
chips with it today.

http://i734.photobucket.com/albums/w...VFDmounted.jpg

http://i734.photobucket.com/albums/w...201200/VFD.jpg

--
Greg O

On 2009-12-14, Greg O wrote:
Pics with the VFD mounted, and all up and running. I actually produced some
chips with it today.

http://i734.photobucket.com/albums/w...VFDmounted.jpg

http://i734.photobucket.com/albums/w...201200/VFD.jpg


Looks way cool. Where is the switch, though?

i

"Ignoramus15449" wrote in message
...
On 2009-12-14, Greg O wrote:
Pics with the VFD mounted, and all up and running. I actually produced
some
chips with it today.

http://i734.photobucket.com/albums/w...VFDmounted.jpg

http://i734.photobucket.com/albums/w...201200/VFD.jpg


Looks way cool. Where is the switch, though?

i

Switch? Switch for what?
I got it set up to run it all through the VFD, and axed the factory on-off
switch. I have forward/reverse, jog, start, and stop. I have the braking set
to one second, which is the lowest setting, so at any speed it will come to
a complete stop in one second, or less. When running the VFD at 30 hertz,
and the variable speed cranked all the way down, about 60 RPM, the spindle
will stop in 1/2 a revolution.
What more do you need?
Greg

On Dec 13, 4:58*pm, "Greg O" wrote:
Pics with the VFD mounted, and all up and running. I actually produced some
chips with it today.

http://i734.photobucket.com/albums/w...tic%201200/VFD...

http://i734.photobucket.com/albums/w...tic%201200/VFD...

--
Greg O

The bins to the left in the picture are empty. What kind of a
metalworker has empty bins?
Paul

"Greg O" wrote in message
...
Pics with the VFD mounted, and all up and running. I actually produced
some chips with it today.

http://i734.photobucket.com/albums/w...VFDmounted.jpg

http://i734.photobucket.com/albums/w...201200/VFD.jpg

--
Greg O


Kool. I mistread it as Problematic drill press. ;)

" wrote in message
...
On Dec 13, 4:58 pm, "Greg O" wrote:
Pics with the VFD mounted, and all up and running. I actually produced
some
chips with it today.

http://i734.photobucket.com/albums/w...tic%201200/VFD...

http://i734.photobucket.com/albums/w...tic%201200/VFD...

--
Greg O

The bins to the left in the picture are empty. What kind of a
metalworker has empty bins?
Paul

Bolt bins, and they are not empty. They are just not real full, just full
enough!
Greg O

Greg O wrote:
Pics with the VFD mounted, and all up and running. I actually produced
some chips with it today.

http://i734.photobucket.com/albums/w...VFDmounted.jpg


http://i734.photobucket.com/albums/w...201200/VFD.jpg


Nice set-up, seems to be missing the OH-SH(T button though. The one that
you can mash when things go wrong and stop it NOW.

--
Steve W.

"Steve W." wrote in message
...
Greg O wrote:
Pics with the VFD mounted, and all up and running. I actually produced
some chips with it today.

http://i734.photobucket.com/albums/w...VFDmounted.jpg


http://i734.photobucket.com/albums/w...201200/VFD.jpg


Nice set-up, seems to be missing the OH-SH(T button though. The one that
you can mash when things go wrong and stop it NOW.

--
Steve W.

The stop button stops the spindle in one second. Fastest braking this VFD
will do.
Good enough "oh ****" button for me.
Greg O

no - that 1 sec "braking" is really a deceleration profile that will power
it for 1 sec on a donward RPM slope - you want the E-stop to cut power to
the motor - every VFD I've ever seen (a few dozen that I've looked at
carefully) had a feature that put it into "neutral" - sometimes you had to
choose but it is always there. Set the "off" switch to "coast" rather than
the decl profile - much safer.

Note that you can have surprises due to too fast decl, such as a screw
mounted thing unscrewing - coast is a much better choice

"Greg O" wrote in message
...

"Steve W." wrote in message
...
Greg O wrote:
Pics with the VFD mounted, and all up and running. I actually produced
some chips with it today.

http://i734.photobucket.com/albums/w...VFDmounted.jpg


http://i734.photobucket.com/albums/w...201200/VFD.jpg


Nice set-up, seems to be missing the OH-SH(T button though. The one that
you can mash when things go wrong and stop it NOW.

--
Steve W.

The stop button stops the spindle in one second. Fastest braking this VFD
will do.
Good enough "oh ****" button for me.
Greg O

On 2009-12-15, Bill Noble wrote:
no - that 1 sec "braking" is really a deceleration profile that will power
it for 1 sec on a donward RPM slope - you want the E-stop to cut power to
the motor - every VFD I've ever seen (a few dozen that I've looked at
carefully) had a feature that put it into "neutral" - sometimes you had to
choose but it is always there. Set the "off" switch to "coast" rather than
the decl profile - much safer.

Note that you can have surprises due to too fast decl, such as a screw
mounted thing unscrewing - coast is a much better choice

You obviously have not tried elecronic deceleration. It may be the
best feature of a VFD on a drill press and other machines.

i

"Bill Noble" wrote in message
...
no - that 1 sec "braking" is really a deceleration profile that will power
it for 1 sec on a donward RPM slope - you want the E-stop to cut power to
the motor - every VFD I've ever seen (a few dozen that I've looked at
carefully) had a feature that put it into "neutral" - sometimes you had to
choose but it is always there. Set the "off" switch to "coast" rather
than the decl profile - much safer.

Note that you can have surprises due to too fast decl, such as a screw
mounted thing unscrewing - coast is a much better choice



Stopping too fast on a drill press?? Never heard of such a concept! I would
rather stop right now, than coast to a stop when something goes to hell!
And what is this screw mounted thing you talk of??
Greg O

On Tue, 15 Dec 2009 18:08:14 -0600, Ignoramus18922
wrote:

On 2009-12-15, Bill Noble wrote:
no - that 1 sec "braking" is really a deceleration profile that will power
it for 1 sec on a donward RPM slope - you want the E-stop to cut power to
the motor - every VFD I've ever seen (a few dozen that I've looked at
carefully) had a feature that put it into "neutral" - sometimes you had to
choose but it is always there. Set the "off" switch to "coast" rather than
the decl profile - much safer.

Note that you can have surprises due to too fast decl, such as a screw
mounted thing unscrewing - coast is a much better choice

You obviously have not tried elecronic deceleration. It may be the
best feature of a VFD on a drill press and other machines.

i


I concure. There are some issues with power stop and coasting..but
frankly..they are less in number and severity when using power stop.


Gunner


"First Law of Leftist Debate
The more you present a leftist with factual evidence
that is counter to his preconceived world view and the
more difficult it becomes for him to refute it without
losing face the chance of him calling you a racist, bigot,
homophobe approaches infinity.

This is despite the thread you are in having not mentioned
race or sexual preference in any way that is relevant to
the subject." Grey Ghost

"Bill Noble" wrote in message
...




so, should I tell you about having a heavy blank unscrew from a wood lathe
when the decel was set too high? you can set your stuff any way you want,
I posted how I set my stuff, and why. I, for the information of whomever
said I had never used "tried electronic deceleration", certainly have done
so, on both a wood and on a metal lathe, and have turned it off on both,
because of negative results.

No arguement over that one, Each machine/situation may need differant
emergency stops setings. Personally, I have never run a machine with a
screwed on face plate or chuck. The only lathes I have run had cam locks,
and reversing motors so quick stops were not an issue.
Going back to the drill press, I see abssolutely no reason not to stop it
quickly, which is where the topic started!

Greg O

"Greg O" wrote in message
...

"Bill Noble" wrote in message
...




so, should I tell you about having a heavy blank unscrew from a wood
lathe when the decel was set too high? you can set your stuff any way
you want, I posted how I set my stuff, and why. I, for the information
of whomever said I had never used "tried electronic deceleration",
certainly have done so, on both a wood and on a metal lathe, and have
turned it off on both, because of negative results.

No arguement over that one, Each machine/situation may need differant
emergency stops setings. Personally, I have never run a machine with a
screwed on face plate or chuck. The only lathes I have run had cam locks,
and reversing motors so quick stops were not an issue.
Going back to the drill press, I see abssolutely no reason not to stop it
quickly, which is where the topic started!

Greg O


Greg - here is why it's a bad idea on a drill press - let's suppose you are
drilling away and the bit jams - it doesn't break the bit and it's pulling
on whatever you were drilling (I don't' know about you, but this does happen
to me from time to time) - if I set the stop to "coast", when I hit stop the
force stops immediately. If I set stop to "decelerate", the force continues
for the length of the deceleration time. I prefer the former.

On Sat, 19 Dec 2009 15:27:15 -0800, Gunner Asch
wrote:

As for me...whenever I use a VFD...it will have a ramp up and a ramp
down time..and the ramp down time will be just about as fast as I can
get it.

I can set the VFD I use for my Bridgeport to stop in 1 second. Would
it be hard on the VFD to come to a quick stop like that? Sould you
have an external add-on resistor if you're going to be doing that? My
VFD is rated at 3 HP and the motor is 2 HP.

RWL

On Sat, 19 Dec 2009 23:34:47 -0500, GeoLane at PTD dot NET GeoLane at
PTD dot NET wrote:

On Sat, 19 Dec 2009 15:27:15 -0800, Gunner Asch
wrote:

As for me...whenever I use a VFD...it will have a ramp up and a ramp
down time..and the ramp down time will be just about as fast as I can
get it.

I can set the VFD I use for my Bridgeport to stop in 1 second. Would
it be hard on the VFD to come to a quick stop like that? Sould you
have an external add-on resistor if you're going to be doing that? My
VFD is rated at 3 HP and the motor is 2 HP.

RWL


It really SHOULD have an external resistor. Its a slush pond that all
the nasty stuff gets sent to when you slam on the brakes. And if you
brake to a stop a lot..it really needs to be what the manual calls for,
given some margin for farting around with surplus goodies.

If you can find something appropriate..you really should install it.
The BP spindle is a fairly massive group of steel chunks and needs a
braking resistor to stop it quickly.

A good wirewound works pretty well, and is adjustable...and are often
damned cheap.



Gunner


"First Law of Leftist Debate
The more you present a leftist with factual evidence
that is counter to his preconceived world view and the
more difficult it becomes for him to refute it without
losing face the chance of him calling you a racist, bigot,
homophobe approaches infinity.

This is despite the thread you are in having not mentioned
race or sexual preference in any way that is relevant to
the subject." Grey Ghost

In article ,
Gunner Asch wrote:

On Sat, 19 Dec 2009 23:34:47 -0500, GeoLane at PTD dot NET GeoLane at
PTD dot NET wrote:

On Sat, 19 Dec 2009 15:27:15 -0800, Gunner Asch
wrote:

As for me...whenever I use a VFD...it will have a ramp up and a ramp
down time..and the ramp down time will be just about as fast as I can
get it.

I can set the VFD I use for my Bridgeport to stop in 1 second. Would
it be hard on the VFD to come to a quick stop like that? Sould you
have an external add-on resistor if you're going to be doing that? My
VFD is rated at 3 HP and the motor is 2 HP.

RWL


It really SHOULD have an external resistor. Its a slush pond that all
the nasty stuff gets sent to when you slam on the brakes. And if you
brake to a stop a lot..it really needs to be what the manual calls for,
given some margin for farting around with surplus goodies.

If you can find something appropriate..you really should install it.
The BP spindle is a fairly massive group of steel chunks and needs a
braking resistor to stop it quickly.

A good wirewound works pretty well, and is adjustable...and are often
damned cheap.

Yes. However, if you use a wirewound resistor not intended as a braking
resistor, there are a few things to ensu

1. If the open-tube vitrified type (which is what adjustable units
usually are), the resistor must be mounted in a grounded metal enclosure
such that no fire will result should the resistor achieve red heat.
This can happen, and will not damage an open-tube vitrified wirewound
resistor if it doesn't happen too often. Be sure to use heater wire to
connect to the resistor. Unless the resistor is too large for such
overheating to occur.

2. The resistor mounting enclosure must prevent accidental contact with
the terminals, as their normal voltage is around 350 volts DC.

3. Entry of and shorting by metal chips must be prevented. Mounting up
high helps a lot.

4. The resistor must be physically large enough to absorb the stored
energy of all that rotating metal without burnout, as no real heat
dissipation can occur over the one-second stopping time. The energy
from stopping is stored in the resistor as heat, which is only later and
slowly transferred to the atmosphere.

For metalworkers, none of this is hard to do, but I wanted to be sure
that the issues are understood. The easiest option is probably a large
aluminum-clad boltdown power resistor. These are available on the
surplus market for small dollars, as are the big open-tube vitrified
units.


Joe Gwinn

" Greg - here is why it's a bad idea on a drill press - let's suppose you
are drilling away and the bit jams - it doesn't break the bit and it's
pulling on whatever you were drilling (I don't' know about you, but this
does happen to me from time to time) - if I set the stop to "coast", when
I hit stop the force stops immediately. If I set stop to "decelerate",
the force continues for the length of the deceleration time. I prefer
the former.

I have the braking set at one second, the lowest setting, but on this VFD
it seems that it will stop sooner, depending on the load, and RPM. At low
RPM, and low spindle speed on the variable it stops in way less than one
second. At 30 Hertz, about 60 RPM, and low speed it will stop in 1/2 a
revolution, or about 1/2 second. At higher speeds even on coast to stop
you have inertia to be concerned about. The way this machine reacts I
believe if the tool is jammed and the motor or spindle stalled the braking
would be instant. Keep in mind on most VFDs, if the motor is stalled, the
braking time is zero, the VFD will not continue to apply power to a
stalled motor after the stop button is pushed because the VFD sees that
the motor is stopped. I guess I don't worry much either way as my reaction
time is slow enough that what ever carnage that results from a problem
will most likely be way over before I can hit the stop button any way!
Greg O


the characteristic you report is apparently dependent on the VFD - on the
Eurotherm drive on my wood lathe, for example, it will power for the entire
ramp down time even if stalled. So, I guess the final answer is "it
depends"

On Sun, 20 Dec 2009 12:49:56 -0500, Joseph Gwinn
wrote:

In article ,
Gunner Asch wrote:

On Sat, 19 Dec 2009 23:34:47 -0500, GeoLane at PTD dot NET GeoLane at
PTD dot NET wrote:

On Sat, 19 Dec 2009 15:27:15 -0800, Gunner Asch
wrote:

As for me...whenever I use a VFD...it will have a ramp up and a ramp
down time..and the ramp down time will be just about as fast as I can
get it.

I can set the VFD I use for my Bridgeport to stop in 1 second. Would
it be hard on the VFD to come to a quick stop like that? Sould you
have an external add-on resistor if you're going to be doing that? My
VFD is rated at 3 HP and the motor is 2 HP.

RWL


It really SHOULD have an external resistor. Its a slush pond that all
the nasty stuff gets sent to when you slam on the brakes. And if you
brake to a stop a lot..it really needs to be what the manual calls for,
given some margin for farting around with surplus goodies.

If you can find something appropriate..you really should install it.
The BP spindle is a fairly massive group of steel chunks and needs a
braking resistor to stop it quickly.

A good wirewound works pretty well, and is adjustable...and are often
damned cheap.

Yes. However, if you use a wirewound resistor not intended as a braking
resistor, there are a few things to ensu

1. If the open-tube vitrified type (which is what adjustable units
usually are), the resistor must be mounted in a grounded metal enclosure
such that no fire will result should the resistor achieve red heat.
This can happen, and will not damage an open-tube vitrified wirewound
resistor if it doesn't happen too often. Be sure to use heater wire to
connect to the resistor. Unless the resistor is too large for such
overheating to occur.

2. The resistor mounting enclosure must prevent accidental contact with
the terminals, as their normal voltage is around 350 volts DC.

3. Entry of and shorting by metal chips must be prevented. Mounting up
high helps a lot.

4. The resistor must be physically large enough to absorb the stored
energy of all that rotating metal without burnout, as no real heat
dissipation can occur over the one-second stopping time. The energy
from stopping is stored in the resistor as heat, which is only later and
slowly transferred to the atmosphere.

For metalworkers, none of this is hard to do, but I wanted to be sure
that the issues are understood. The easiest option is probably a large
aluminum-clad boltdown power resistor. These are available on the
surplus market for small dollars, as are the big open-tube vitrified
units.


Joe Gwinn


Very well stated Joe. I tend to simplify things perhaps too much for
some readers.

Gunner


"First Law of Leftist Debate
The more you present a leftist with factual evidence
that is counter to his preconceived world view and the
more difficult it becomes for him to refute it without
losing face the chance of him calling you a racist, bigot,
homophobe approaches infinity.

This is despite the thread you are in having not mentioned
race or sexual preference in any way that is relevant to
the subject." Grey Ghost

My Teco VFD specifies a 70 Ohm, 200 Watt braking resistor. I did
some quick looking on eBay and Mouser. It looks like the least
expensive ones are the open tube ones - BUT at around $33 and up. Is
there a less expensive place to buy these or a different way to search
either site that would bring up the less expensive alternatives?


RWL

look for a 200 watt heating element, or put several higher wattage units in
series

GeoLane at PTD dot NET wrote in message
...

My Teco VFD specifies a 70 Ohm, 200 Watt braking resistor. I did
some quick looking on eBay and Mouser. It looks like the least
expensive ones are the open tube ones - BUT at around $33 and up. Is
there a less expensive place to buy these or a different way to search
either site that would bring up the less expensive alternatives?


RWL

GeoLane at PTD dot NET GeoLane at PTD dot NET writes:


My Teco VFD specifies a 70 Ohm, 200 Watt braking resistor. I did
some quick looking on eBay and Mouser. It looks like the least
expensive ones are the open tube ones - BUT at around $33 and up. Is
there a less expensive place to buy these or a different way to search
either site that would bring up the less expensive alternatives?


Think suplus places as well. You can use multiple resistors if
you don't mind the simple math.



--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

On Sun, 20 Dec 2009 23:53:58 -0500, GeoLane at PTD dot NET GeoLane at
PTD dot NET wrote:


My Teco VFD specifies a 70 Ohm, 200 Watt braking resistor. I did
some quick looking on eBay and Mouser. It looks like the least
expensive ones are the open tube ones - BUT at around $33 and up. Is
there a less expensive place to buy these or a different way to search
either site that would bring up the less expensive alternatives?


RWL


One can get away with a 100 watt tubular or solid resistor if you are
simply operating it HSM and not doing rapid starts and stops ie CNC.

Surplus houses often have similar resistors btw....google is your
friend.


Such as this page....time to find it less than 1 minute...

http://www.surplussales.com/resistor.../WW70-110.html



Gunner


"First Law of Leftist Debate
The more you present a leftist with factual evidence
that is counter to his preconceived world view and the
more difficult it becomes for him to refute it without
losing face the chance of him calling you a racist, bigot,
homophobe approaches infinity.

This is despite the thread you are in having not mentioned
race or sexual preference in any way that is relevant to
the subject." Grey Ghost

On 2009-12-19, Greg O wrote:

"Bill Noble" wrote in message
...

[ ... ]

Greg - here is why it's a bad idea on a drill press - let's suppose you
are drilling away and the bit jams - it doesn't break the bit and it's
pulling on whatever you were drilling (I don't' know about you, but this
does happen to me from time to time) - if I set the stop to "coast", when
I hit stop the force stops immediately. If I set stop to "decelerate",
the force continues for the length of the deceleration time. I prefer the
former.

I have the braking set at one second, the lowest setting, but on this VFD it
seems that it will stop sooner, depending on the load, and RPM. At low RPM,
and low spindle speed on the variable it stops in way less than one second.
At 30 Hertz, about 60 RPM, and low speed it will stop in 1/2 a revolution,
or about 1/2 second. At higher speeds even on coast to stop you have inertia
to be concerned about. The way this machine reacts I believe if the tool is
jammed and the motor or spindle stalled the braking would be instant. Keep
in mind on most VFDs, if the motor is stalled, the braking time is zero, the
VFD will not continue to apply power to a stalled motor after the stop
button is pushed because the VFD sees that the motor is stopped. I guess I
don't worry much either way as my reaction time is slow enough that what
ever carnage that results from a problem will most likely be way over before
I can hit the stop button any way!

I have a three-phase motor which I plan to add to my 12x24"
Clausing lathe (currently has a single-phase motor), and since it has a
L-00 spindle, I consider having both stops to be better. A normal stop
with the deceleration set in the VFD (to whatever works with the most
massive chuck, a reasonable size workpiece, and the highest spindle
speed without tripping the limits on the VFD.) But when things are
really going bad, the motor which I am installing has an electrically
operated brake (actually, the brake is released by power, not actuated
by it), so I will set up the emergency stop switch to drop power from
the input to the VFD and to the brake so the motor and spindle will stop
in the shortest possible time.

FWIW The motor originally was the spindle motor on one of the big
washing-machine style disk drives from mainframe computer
centers. I got it at a hamfest.

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

note also that you can use a light bulb

"David Lesher" wrote in message
...
GeoLane at PTD dot NET GeoLane at PTD dot NET writes:


My Teco VFD specifies a 70 Ohm, 200 Watt braking resistor. I did
some quick looking on eBay and Mouser. It looks like the least
expensive ones are the open tube ones - BUT at around $33 and up. Is
there a less expensive place to buy these or a different way to search
either site that would bring up the less expensive alternatives?


Think suplus places as well. You can use multiple resistors if
you don't mind the simple math.



--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

On Mon, 21 Dec 2009 00:32:15 -0800, "Bill Noble"
wrote:

note also that you can use a light bulb

"David Lesher" wrote in message
...
GeoLane at PTD dot NET GeoLane at PTD dot NET writes:


My Teco VFD specifies a 70 Ohm, 200 Watt braking resistor. I did
some quick looking on eBay and Mouser. It looks like the least
expensive ones are the open tube ones - BUT at around $33 and up. Is
there a less expensive place to buy these or a different way to search
either site that would bring up the less expensive alternatives?



Do NOT use a light bulb. The cold resistance of a light bulb can
be less than 1/6th of its nominal hot resistance and this much
lower resistance overloads the VFD braking circuit.

Jim

On Sun, 20 Dec 2009 23:53:58 -0500, GeoLane at PTD dot NET GeoLane at
PTD dot NET wrote:


My Teco VFD specifies a 70 Ohm, 200 Watt braking resistor. I did
some quick looking on eBay and Mouser. It looks like the least
expensive ones are the open tube ones - BUT at around $33 and up. Is
there a less expensive place to buy these or a different way to search
either site that would bring up the less expensive alternatives?

Try it without the resistor first. In my experience it's pretty tough
to trip a VFD decelerating a Bridgeport spindle in any reasonable
time. I have my mill set to 1s accel and decel and have never tripped
it. This is with an older Mitsubishi drive which does have a small
internal resistor, with provision to add more capacity externally.
Similar experience with my previous mill and a different Mitsu VFD.

If your drive has the ability to display the DC bus voltage (a common
feature) you can get an idea how close you are to tripping on
overvoltage before you spend time and money installing a resistor.

I recently built a machine that includes a 5HP gearmotor lifting and
lowering a 2000+ pound load at up to 12 in/s. My customer built the
controls and I was concerned that they were not installing an external
braking resistor on the little AB Powerflex VFD. Very bad things will
happen if the drive trips. We tested the thing extensively and were
not able to trip the drive.

--
Ned Simmons

On Sun, 20 Dec 2009 23:53:58 -0500, GeoLane at PTD dot NET GeoLane at
PTD dot NET wrote:


My Teco VFD specifies a 70 Ohm, 200 Watt braking resistor. I did
some quick looking on eBay and Mouser. It looks like the least
expensive ones are the open tube ones - BUT at around $33 and up. Is
there a less expensive place to buy these or a different way to search
either site that would bring up the less expensive alternatives?


A couple of 250W incandescent bulbs in series will work, having a cold
resistance of about 10ohms, and a hot resistance of about 100 ohms.
They'll heat up to incandescence almost instantly (in just a couple of
cycles).

OTOH, there'll be a 100ms or so of very dramatic braking before the
filaments heat; maybe more than the VFD's output transistors can take --
dunno. Most will handle it just fine, but might trip on overcurrent.

$33/resistor isn't all that expensive, if you need more braking than the
VFD will provide without them.

LLoyd

On Mon, 21 Dec 2009 10:20:58 +0000, wrote:

On Mon, 21 Dec 2009 00:32:15 -0800, "Bill Noble"
wrote:

note also that you can use a light bulb

"David Lesher" wrote in message
...
GeoLane at PTD dot NET GeoLane at PTD dot NET writes:


My Teco VFD specifies a 70 Ohm, 200 Watt braking resistor. I did
some quick looking on eBay and Mouser. It looks like the least
expensive ones are the open tube ones - BUT at around $33 and up. Is
there a less expensive place to buy these or a different way to search
either site that would bring up the less expensive alternatives?



Do NOT use a light bulb. The cold resistance of a light bulb can
be less than 1/6th of its nominal hot resistance and this much
lower resistance overloads the VFD braking circuit.

Jim


Indeed!!!

Gunner




"First Law of Leftist Debate
The more you present a leftist with factual evidence
that is counter to his preconceived world view and the
more difficult it becomes for him to refute it without
losing face the chance of him calling you a racist, bigot,
homophobe approaches infinity.

This is despite the thread you are in having not mentioned
race or sexual preference in any way that is relevant to
the subject." Grey Ghost

The large open end ones with ribbon wire - are called 'corn cob' power resistors.

I have two smooth sided resistors - each 8 ohm (nice speaker loads)
but must be 1000 watt. I'd have to look. I also have a 1/2 ohm IIRC
corn cob. Nice to measure current flow in a circuit - voltage drop.

$33 isn't bad for that - I'm surprised myself.

If you get one, look for mounting hardware. It helps. Or you make some.


Martin

GeoLane at PTD dot NET wrote:
My Teco VFD specifies a 70 Ohm, 200 Watt braking resistor. I did
some quick looking on eBay and Mouser. It looks like the least
expensive ones are the open tube ones - BUT at around $33 and up. Is
there a less expensive place to buy these or a different way to search
either site that would bring up the less expensive alternatives?


RWL

"Martin H. Eastburn" wrote in
:

The large open end ones with ribbon wire - are called 'corn cob' power
resistors.

I have two smooth sided resistors - each 8 ohm (nice speaker loads)
but must be 1000 watt. I'd have to look. I also have a 1/2 ohm IIRC
corn cob. Nice to measure current flow in a circuit - voltage drop.

$33 isn't bad for that - I'm surprised myself.

If you get one, look for mounting hardware. It helps. Or you make
some.

I like the ones in aluminum housings, like these:

http://www.token.com.tw/resistor-pd/...esistor-ah.htm

They are less fragile than the ceramic ones, and tend to be a bit smaller
for a given rating. Several vendors make them, and they are available
surplus from time to time. Be careful with the power ratings, however.
They assume a certain level of air flow & heat sinking for continuous
duty. For the 200W braking resistor, you could probably get away with a
200 W rating without heroics because the load is transient.

Doug White

"Doug White" wrote in message
...
"Martin H. Eastburn" wrote in
:

The large open end ones with ribbon wire - are called 'corn cob' power
resistors.

I have two smooth sided resistors - each 8 ohm (nice speaker loads)
but must be 1000 watt. I'd have to look. I also have a 1/2 ohm IIRC
corn cob. Nice to measure current flow in a circuit - voltage drop.

$33 isn't bad for that - I'm surprised myself.

If you get one, look for mounting hardware. It helps. Or you make
some.

I like the ones in aluminum housings, like these:

http://www.token.com.tw/resistor-pd/...esistor-ah.htm

They are less fragile than the ceramic ones, and tend to be a bit smaller
for a given rating. Several vendors make them, and they are available
surplus from time to time. Be careful with the power ratings, however.
They assume a certain level of air flow & heat sinking for continuous
duty. For the 200W braking resistor, you could probably get away with a
200 W rating without heroics because the load is transient.

Doug White

Give a call to http://www.halted.com/ large surplus dealer in Sunnyvale.

On Tue, 22 Dec 2009 13:36:02 GMT, Doug White
wrote:

"Martin H. Eastburn" wrote in
:

The large open end ones with ribbon wire - are called 'corn cob' power
resistors.

I have two smooth sided resistors - each 8 ohm (nice speaker loads)
but must be 1000 watt. I'd have to look. I also have a 1/2 ohm IIRC
corn cob. Nice to measure current flow in a circuit - voltage drop.

$33 isn't bad for that - I'm surprised myself.

If you get one, look for mounting hardware. It helps. Or you make
some.

I like the ones in aluminum housings, like these:

http://www.token.com.tw/resistor-pd/...esistor-ah.htm

They are less fragile than the ceramic ones, and tend to be a bit smaller
for a given rating. Several vendors make them, and they are available
surplus from time to time. Be careful with the power ratings, however.
They assume a certain level of air flow & heat sinking for continuous
duty. For the 200W braking resistor, you could probably get away with a
200 W rating without heroics because the load is transient.

Doug White


Some other styles....

http://omniturn.com/bin/RepairParts/...components.htm

A bit pricey however.....G

Gunner


"First Law of Leftist Debate
The more you present a leftist with factual evidence
that is counter to his preconceived world view and the
more difficult it becomes for him to refute it without
losing face the chance of him calling you a racist, bigot,
homophobe approaches infinity.

This is despite the thread you are in having not mentioned
race or sexual preference in any way that is relevant to
the subject." Grey Ghost

In article ,
Gunner Asch wrote:

On Tue, 22 Dec 2009 13:36:02 GMT, Doug White
wrote:

"Martin H. Eastburn" wrote in
:

The large open end ones with ribbon wire - are called 'corn cob' power
resistors.

I have two smooth sided resistors - each 8 ohm (nice speaker loads)
but must be 1000 watt. I'd have to look. I also have a 1/2 ohm IIRC
corn cob. Nice to measure current flow in a circuit - voltage drop.

$33 isn't bad for that - I'm surprised myself.

If you get one, look for mounting hardware. It helps. Or you make
some.

I like the ones in aluminum housings, like these:

http://www.token.com.tw/resistor-pd/...esistor-ah.htm

They are less fragile than the ceramic ones, and tend to be a bit smaller
for a given rating. Several vendors make them, and they are available
surplus from time to time. Be careful with the power ratings, however.
They assume a certain level of air flow & heat sinking for continuous
duty. For the 200W braking resistor, you could probably get away with a
200 W rating without heroics because the load is transient.

Doug White


Some other styles....

http://omniturn.com/bin/RepairParts/...components.htm

Do you know what these braking resistor units weigh? (Not shipping
weight, actual weight.)

The reason to ask is to estimate the amount of heat they can absorb
without allowing smoke to escape.


A bit pricey however.....G

But pretty.


Joe Gwinn

On Tue, 22 Dec 2009 17:06:29 -0500, Joseph Gwinn
wrote:

In article ,
Gunner Asch wrote:

On Tue, 22 Dec 2009 13:36:02 GMT, Doug White
wrote:

"Martin H. Eastburn" wrote in
:

The large open end ones with ribbon wire - are called 'corn cob' power
resistors.

I have two smooth sided resistors - each 8 ohm (nice speaker loads)
but must be 1000 watt. I'd have to look. I also have a 1/2 ohm IIRC
corn cob. Nice to measure current flow in a circuit - voltage drop.

$33 isn't bad for that - I'm surprised myself.

If you get one, look for mounting hardware. It helps. Or you make
some.

I like the ones in aluminum housings, like these:

http://www.token.com.tw/resistor-pd/...esistor-ah.htm

They are less fragile than the ceramic ones, and tend to be a bit smaller
for a given rating. Several vendors make them, and they are available
surplus from time to time. Be careful with the power ratings, however.
They assume a certain level of air flow & heat sinking for continuous
duty. For the 200W braking resistor, you could probably get away with a
200 W rating without heroics because the load is transient.

Doug White


Some other styles....

http://omniturn.com/bin/RepairParts/...components.htm

Do you know what these braking resistor units weigh? (Not shipping
weight, actual weight.)

Ayup..they are about 1-1.5 lbs. They can absorb a ****LOAD of heat,
and transfer it to whatever they are bolted to. I think the big units
rated for Short Cycle are about 5lbs or a bit more.

4000 rpm to zero in less than a second, loading, then back to 4000 rpm,
then back to zero..often times every 3-5 seconds all day long.

The reason to ask is to estimate the amount of heat they can absorb
without allowing smoke to escape.


A bit pricey however.....G

But pretty.


Joe Gwinn


Gunner, OmniTurn Service tech



"First Law of Leftist Debate
The more you present a leftist with factual evidence
that is counter to his preconceived world view and the
more difficult it becomes for him to refute it without
losing face the chance of him calling you a racist, bigot,
homophobe approaches infinity.

This is despite the thread you are in having not mentioned
race or sexual preference in any way that is relevant to
the subject." Grey Ghost

another good source is Ford Electronics in Fullerton CA - they used to have
a reasonable selection of large surplus resistors

"Bill McKee" wrote in message
m...

"Doug White" wrote in message
...
"Martin H. Eastburn" wrote in
:

The large open end ones with ribbon wire - are called 'corn cob' power
resistors.

I have two smooth sided resistors - each 8 ohm (nice speaker loads)
but must be 1000 watt. I'd have to look. I also have a 1/2 ohm IIRC
corn cob. Nice to measure current flow in a circuit - voltage drop.

$33 isn't bad for that - I'm surprised myself.

If you get one, look for mounting hardware. It helps. Or you make
some.

I like the ones in aluminum housings, like these:

http://www.token.com.tw/resistor-pd/...esistor-ah.htm

They are less fragile than the ceramic ones, and tend to be a bit smaller
for a given rating. Several vendors make them, and they are available
surplus from time to time. Be careful with the power ratings, however.
They assume a certain level of air flow & heat sinking for continuous
duty. For the 200W braking resistor, you could probably get away with a
200 W rating without heroics because the load is transient.

Doug White

Give a call to http://www.halted.com/ large surplus dealer in Sunnyvale.

On Tue, 22 Dec 2009 16:08:09 -0800, "Bill Noble"
wrote:

another good source is Ford Electronics in Fullerton CA - they used to have
a reasonable selection of large surplus resistors

They are about 5 minutes from my shop in Fullerton. Ive driven by there
a number of times in the past month. Ill have to stop in and see what
they have.

Gunner


"Bill McKee" wrote in message
om...

"Doug White" wrote in message
...
"Martin H. Eastburn" wrote in
:

The large open end ones with ribbon wire - are called 'corn cob' power
resistors.

I have two smooth sided resistors - each 8 ohm (nice speaker loads)
but must be 1000 watt. I'd have to look. I also have a 1/2 ohm IIRC
corn cob. Nice to measure current flow in a circuit - voltage drop.

$33 isn't bad for that - I'm surprised myself.

If you get one, look for mounting hardware. It helps. Or you make
some.

I like the ones in aluminum housings, like these:

http://www.token.com.tw/resistor-pd/...esistor-ah.htm

They are less fragile than the ceramic ones, and tend to be a bit smaller
for a given rating. Several vendors make them, and they are available
surplus from time to time. Be careful with the power ratings, however.
They assume a certain level of air flow & heat sinking for continuous
duty. For the 200W braking resistor, you could probably get away with a
200 W rating without heroics because the load is transient.

Doug White

Give a call to http://www.halted.com/ large surplus dealer in Sunnyvale.



"First Law of Leftist Debate
The more you present a leftist with factual evidence
that is counter to his preconceived world view and the
more difficult it becomes for him to refute it without
losing face the chance of him calling you a racist, bigot,
homophobe approaches infinity.

This is despite the thread you are in having not mentioned
race or sexual preference in any way that is relevant to
the subject." Grey Ghost

In article ,
Gunner Asch wrote:

On Tue, 22 Dec 2009 17:06:29 -0500, Joseph Gwinn
wrote:

In article ,
Gunner Asch wrote:

On Tue, 22 Dec 2009 13:36:02 GMT, Doug White
wrote:

"Martin H. Eastburn" wrote in
:

The large open end ones with ribbon wire - are called 'corn cob' power
resistors.

I have two smooth sided resistors - each 8 ohm (nice speaker loads)
but must be 1000 watt. I'd have to look. I also have a 1/2 ohm IIRC
corn cob. Nice to measure current flow in a circuit - voltage drop.

$33 isn't bad for that - I'm surprised myself.

If you get one, look for mounting hardware. It helps. Or you make
some.

I like the ones in aluminum housings, like these:

http://www.token.com.tw/resistor-pd/...esistor-ah.htm

They are less fragile than the ceramic ones, and tend to be a bit smaller
for a given rating. Several vendors make them, and they are available
surplus from time to time. Be careful with the power ratings, however.
They assume a certain level of air flow & heat sinking for continuous
duty. For the 200W braking resistor, you could probably get away with a
200 W rating without heroics because the load is transient.

Doug White


Some other styles....

http://omniturn.com/bin/RepairParts/...components.htm

Do you know what these braking resistor units weigh? (Not shipping
weight, actual weight.)

Ayup..they are about 1-1.5 lbs. They can absorb a ****LOAD of heat,
and transfer it to whatever they are bolted to. I think the big units
rated for Short Cycle are about 5lbs or a bit more.

4000 rpm to zero in less than a second, loading, then back to 4000 rpm,
then back to zero..often times every 3-5 seconds all day long.

Thanks, that gives us the scale.

For the record, the Hitachi braking resistors JRB 120-series (120 watts)
weigh 0.27 Kg (0.59 lbs), SRB-200-series weigh 0.97 Kg (2.13 lbs),
SRB-300 weigh 1.68 Kg (3.70 lbs), and SRB-400 weighs 2.85 Kg (6.27 lbs),
according to the datasheet.

I have a JRB-120-3 (50 ohms) on the Clausing 5914 lathe's SJ100 VFD, and
I can trip the VFD if I stop too quickly with a big chuck installed.
Don't recall if I can use a lower resistance or not. But I can stop in
2 or 3 seconds, which is good enough for a manual lathe.

Joe

"Gunner Asch" wrote in message
...
On Tue, 22 Dec 2009 16:08:09 -0800, "Bill Noble"
wrote:

another good source is Ford Electronics in Fullerton CA - they used to
have
a reasonable selection of large surplus resistors

They are about 5 minutes from my shop in Fullerton. Ive driven by there
a number of times in the past month. Ill have to stop in and see what
they have.

Gunner


"Bill McKee" wrote in message
news:ENSdnbOBs9L0vKzWnZ2dnUVZ_gOdnZ2d@earthlink. com...

"Doug White" wrote in message
...
"Martin H. Eastburn" wrote in
:

The large open end ones with ribbon wire - are called 'corn cob' power
resistors.

I have two smooth sided resistors - each 8 ohm (nice speaker loads)
but must be 1000 watt. I'd have to look. I also have a 1/2 ohm IIRC
corn cob. Nice to measure current flow in a circuit - voltage drop.

$33 isn't bad for that - I'm surprised myself.

If you get one, look for mounting hardware. It helps. Or you make
some.

I like the ones in aluminum housings, like these:

http://www.token.com.tw/resistor-pd/...esistor-ah.htm

They are less fragile than the ceramic ones, and tend to be a bit
smaller
for a given rating. Several vendors make them, and they are available
surplus from time to time. Be careful with the power ratings, however.
They assume a certain level of air flow & heat sinking for continuous
duty. For the 200W braking resistor, you could probably get away with
a
200 W rating without heroics because the load is transient.

Doug White

Give a call to http://www.halted.com/ large surplus dealer in Sunnyvale.



"First Law of Leftist Debate
The more you present a leftist with factual evidence
that is counter to his preconceived world view and the
more difficult it becomes for him to refute it without
losing face the chance of him calling you a racist, bigot,
homophobe approaches infinity.

This is despite the thread you are in having not mentioned
race or sexual preference in any way that is relevant to
the subject." Grey Ghost


Big light bulbs. Resistance may be wrong, but they absorb a lot of energy.
We used a bank of light bulbs as a dummy load on a TACAN unit. Absorbing
3000 watts.

Bill McKee wrote:

"Gunner Asch" wrote in message
...
On Tue, 22 Dec 2009 16:08:09 -0800, "Bill Noble"
wrote:

another good source is Ford Electronics in Fullerton CA - they used to
have
a reasonable selection of large surplus resistors
They are about 5 minutes from my shop in Fullerton. Ive driven by there
a number of times in the past month. Ill have to stop in and see what
they have.

Gunner

"Bill McKee" wrote in message
m...
"Doug White" wrote in message
...
"Martin H. Eastburn" wrote in
:

The large open end ones with ribbon wire - are called 'corn cob' power
resistors.

I have two smooth sided resistors - each 8 ohm (nice speaker loads)
but must be 1000 watt. I'd have to look. I also have a 1/2 ohm IIRC
corn cob. Nice to measure current flow in a circuit - voltage drop.

$33 isn't bad for that - I'm surprised myself.

If you get one, look for mounting hardware. It helps. Or you make
some.
I like the ones in aluminum housings, like these:

http://www.token.com.tw/resistor-pd/...esistor-ah.htm

They are less fragile than the ceramic ones, and tend to be a bit
smaller
for a given rating. Several vendors make them, and they are available
surplus from time to time. Be careful with the power ratings, however.
They assume a certain level of air flow & heat sinking for continuous
duty. For the 200W braking resistor, you could probably get away with
a
200 W rating without heroics because the load is transient.

Doug White
Give a call to http://www.halted.com/ large surplus dealer in Sunnyvale.



Big light bulbs. Resistance may be wrong, but they absorb a lot of energy.
We used a bank of light bulbs as a dummy load on a TACAN unit. Absorbing
3000 watts.


We've had good luck using ordinary hardware store kitchen range heater
elements (tradename Calrod). Cheap, low resistance, high power dissipation.

Carla

Next time you're stopped, just jump out and DEMAND proof of probable
cause. Don't forget to call him PIG! and JACKBOOTED THUG! Ask for his
badge number. Tell him you pay his salary. They like that.