PDA

View Full Version : Replicating a solenoid?



Boucher
11-08-2012, 02:22 PM
This is the solenoid for the Spindle brake discussed in another thread regarding my Nardini 1230E.
http://i109.photobucket.com/albums/n50/boucherbyron/MagneticBrakeSolenoid.jpg

With it encapsulated within the steel part how would one go about trying to determine wire size and number of turns to wind another one?

Black Forest
11-08-2012, 02:30 PM
Silly boy. A can opener!

ed_h
11-08-2012, 02:56 PM
If you can estimate the cross sectional area of the coil itself, you might get close by using that and the DC resistance.

Boucher
11-08-2012, 03:02 PM
Well the last time I used the can opener I opened this can of worms. If necessary I can live without the brake but I would very much prefer to restore its functionally.

ed_h The coil failed open.

macona
11-08-2012, 03:08 PM
Assuming the coil potting is the only non-metal part of the brake magnet, put it in an oven set to max and burn out the potting/enamel. Then pull out the winding, count the wires, measure, and rewind.

Did you see if the magnet is still available from the brake manufacturer?

Boucher
11-08-2012, 03:11 PM
Is there any possibility that the steel housing could be heated enough to pop the coil out? Or the other direction could it be frozen and popped out?

MaxHeadRoom
11-08-2012, 03:22 PM
It's what, just over an inch deep? maybe press it out?
You would have to figure a way of repotting to retain the concentricity of the inner to outer, so a jig may have to be made, when re-potting.
When you pop the coil out, it can be sawed in two and the turns/gauge can be obtained.
If the steel parts are all one then you may have to chip it out and just destroy the coil only.
Max.

ed_h
11-08-2012, 03:25 PM
ed_h The coil failed open.

Dang. That makes it harder.

Do you know anything about the current/voltage ratings?

becksmachine
11-08-2012, 03:58 PM
Well the last time I used the can opener I opened this can of worms.

Very true, but it is your (our?) destiny!! :D

So, you must realize that you are now obligated to use your new found "opener" talents on beverages of you choice. :)

It helps the repair process start to ferment properly.

Dave

Boucher
11-08-2012, 03:59 PM
Macona, The encapsulation looks more like an Epoxy than the wire type Enamel. It obviously has the enamel wire inside that. The brake is an integral part of the WEG motor built in Brazil before 1988. I havenít had much luck navigating their on line manuals. This is the nameplate.
http://i109.photobucket.com/albums/n50/boucherbyron/LatheMotorLabelSmall.jpg

Another thing that I donít comprehend is the label that indicates that the brake is 220V .

I can re measure the voltage but I thought it was much lower.

The encapsulation is in a steel ring so there is no access to the back side.

Boucher
11-08-2012, 04:09 PM
Dave, I think you are right. Time for gentleman Jack and I to retire to the patio and watch the wildlife. The temperature is 80įF. Some earlier cooler temperatures has the Bucks chasing the Does. It has got to be 5 o’clock somewhere.

ed_h
11-08-2012, 04:12 PM
Boucher--

You don't have much to go on here. Since the coil is toast anyway, maybe you can take a "core sample" with a smallish hole saw. This would establish the wire gage, and a way to estimate the number of turns.

You might also try some solvents to see if they would soften the potting. It will probably take something like Acetone or Methylene Chloride.

oldtiffie
11-08-2012, 04:27 PM
Repair by replacement (new item)?

If not it looks like going without the brake.

J. R. Williams
11-08-2012, 04:42 PM
I would heat the potting to soften the material and start digging. Wind a new coil and cast it in place with some material like "bondo'.

ckalley
11-08-2012, 04:46 PM
If you can find a solvent to 'disolve' the epoxy potting, it would probably be something you would NOT want to get very close to. I think ed_h's idea of the core sample would be the place to start so you can get an idea of the wire size, number of turns, etc. I would suggest heating the whole assembly up to 400-500F to break down the epoxy and then try digging the coil out of the steel ring and then go from there. You will probably find some kind of high-temp tape and possibly a bobbin or form that the coil was wound on. We wind coils (sorry, not the type you need) where I work, so I'd be happy to assist with how to get a new coil made.

There is lots of magnet wire listed on e-bay and a lot of it is the 200C rated stuff, which is what I'd recommend.

I also have a Nardini lathe (12x30) and have always had the question about what happens if the motor goes TU.... I'd be affraid to ask what a replacement would cost!

Craig

richz
11-08-2012, 04:49 PM
Any electric motor should be able to rewind it.

ckelloug
11-08-2012, 04:59 PM
The correct solvents for getting rid of epoxy are dimethyl formamide and possibly n-Methyl-Pyrrolidone which are hard to come by. You might also have some luck boiling it in DMSO which is sometimes available in health food stores as a home baldness remedy and other bad ideas. . . The DMSO generally doesn't dissolve the epoxy well but it's usually been enough for me to get the epoxy to unstick from metals like stir bars and lab spatulas.

Acetone is generally not very effective against epoxy. Methylene chloride may be effective against some epoxies but the low boiling point makes it hard to keep it on the part.

On the other hand, if you can destroy the whole steel part you can cross section it and if you can remove the copper smear in the cut, you should be able to count the coil wires
and make a whole new part.

MaxHeadRoom
11-08-2012, 05:12 PM
Another thing that I donít comprehend is the label that indicates that the brake is 220V .

I can re measure the voltage but I thought it was much lower.



Like I asked in the other thread, what is the secondary voltage of the control TXFMR that feeds it?
It looks like either 110 or 220, too blurred to read exactly.
This will tell you right off.
Max.

JoeCB
11-08-2012, 05:23 PM
cut a short section out of the potted winding... use a sharp blade chisel like an old wood chisel that you don't mind beating up. Once you ket the wire info just proceed in digging out the rest. Good suggestion on making a concentricity fixture BEFORE you start hacking.
Joe B

browne92
11-08-2012, 06:19 PM
There are some good tips from the folks that make the stuff:

http://www.pottingsolutions.com/my%20site/Technology/potting_hints.htm

And someone that makes solvents:

http://www.dynaloy.com/dynaloy-chemical-solutions-products/specialty-chemistries/potting-removers-encapsulation-removers.html

No idea of price, but I doubt it's cheap

Good luck.

oldtiffie
11-08-2012, 07:12 PM
Why not get an opinion and a quote from a re-wind shop?

Weston Bye
11-08-2012, 07:28 PM
We build and rebuild coils with similar-looking epoxy where I work. In the morning I will ask the guy who usually does it.

atomarc
11-08-2012, 07:45 PM
Assuming the coil potting is the only non-metal part of the brake magnet, put it in an oven set to max and burn out the potting/enamel. Then pull out the winding, count the wires, measure, and rewind.

Did you see if the magnet is still available from the brake manufacturer?

+1 On this procedure! This is SOP in a motor shop. The coil is 'glued' into the brake housing with epoxy and certainly isn't going to 'pop' out. Why are you confused over the brake operating voltage..isn't it exactly the same voltage as that 3 phase motor powering the lathe!

Before I cooked that brake out I would make absolutely 100% sure it really has failed 'open'! Potted coils are usually pretty bulletproof. Wiggle around where the pigtail comes out and maybe you will find a broken wire you can repair without doing invasive surgery.

Make sure your VOM was working properly and on the correct scale to read the resistance or continuity. Eliminate all the simple things before taking drastic measures.

Stuart

John Stevenson
11-08-2012, 07:48 PM
Local rewind company burns the resin out and then removes the damaged coil.
Wire size is easy to sort out and then they wind a new coil, same size wire until it looks the same as the old one.
Number of turns on these isn't that critical and they can always compare by weight to get close enough.

kf2qd
11-08-2012, 09:04 PM
Find the wire size, and number of turns - is it 1 coil or 2, and such. Make a fixture in your lathe that has the same width and the smaller ID and carefully wind a new one at low speed. whe oyu are done, carefully remove it from the winding forma and slide it into the housing and repot with epoxy. If you were to line the winding fixture with saran wrap or waxed paper you could even mix small amounts of potting epoxy in while you were winding and have an easier to manipulate coil when ready to install. Figure out the lenght and wire size and got to your local winding shop and see if they have an almost empty bucket of the good wire. Might be able to get it for a simple song...

wierdscience
11-08-2012, 09:24 PM
What John said,also all you need to burn it out is a gas BBQ grill,cook it till the smoke turns white,let cool.Shake out bead blast/clean real good the armature then wind up the new coil as kf2 said.

If the coil is for intermittent operation almost any good two part epoxy will work for winding and potting so long as it isn't metal filled.If the coil is for continuous operation,then search out the correct potting compound at EIS.It needs to be thermally conductive to dissipate heat into the armature and away from the windings.

lakeside53
11-08-2012, 09:28 PM
Are you sure the coil is bad? Is that 220v DC? Your schematic showed a bridge rectifier. What is the AC voltage FEEDING the bridge?

If it is bad, why not just buy another from Nardini?

On my Polamco, I fixed my open circuit coil - the enamal wire right at the termination was bad. Resoldered it and it worked like new.

If you do want to make your own coil, no need to "burn". Just chuck up the solenoid and turn out the old potting compound and wires.

J Tiers
11-08-2012, 09:49 PM
Can you determine the normal DC current drawn by the coil?

If so, you can get the resistance from that and the voltage. With that,you should be able to estimate the wire size by the probable available volume of the winding area and the resistance per foot of the wire. The average length of 1 turn is the circumference of a turn in the middle of the space.

You will be removing the old coil, so if you can do the above, you can check your coil two ways, ensuring a check on bad measurement or other causes of error..

darryl
11-08-2012, 10:24 PM
Looks odd to me- it appears to have a hollow steel core, with an outer steel ring or tube surrounding it. The space between would be where the winding would go. So what's all the outer 'stuff'? If there's windings around the outside of the larger steel 'core' that is seen, then that would imply that a flux path should exist outside of that module. Is there an outer steel housing that goes over that module?

If it's dead, I would first cut into the potting compound on the outside top edge to see if you actually do run into copper. If you do, stop immediately and take a resistance measurement again, from either wire to a probe that can be jammed into the cut. You would likely be tapping into the wire at or near the end of the winding, since it would be on the outside. If you get a resistance reading, it might be pretty close to what the full coil is supposed to be. You might even be able to drill and chip away at that point to access the copper and make a connection to it. That could be the fix and it would work again. If you don't get a reading, that probably means that the break is closer to the inside, or first layer of the winding. If that's the case, you're screwed to fix it. Worth a shot to try that anyway.

But that's assuming there's winding in that outer layer of potting. I would expect the winding to actually be between the two steel parts that are seen, in which case you might carefully drill a semi-circle of holes around where the wires lead out, then attempt to break out the central chunk of compound. With luck, you will have accessed the point where the wires lead in and out of the coil. With even more luck, you might find the break right near that point. I think that's worth a shot as well- what can you lose except a few minutes of carefully drilling away some potting compound.

EddyCurr
11-08-2012, 10:33 PM
Is the OP determined to implement an HSM solution?

If not, the WEG Service Network Locator (http://www.weg.net/ca/Contact/Service-Network) suggests that the following TX firms might
be able to be of assistance


FLANDERS ELECTRIC INC.
901 W. Harrison Rd
LONGVIEW, TX 75604
TX
United States
Phone(s): 903-759-9439
Fax: 903-297-9939
Email: kgarbs@flanderselectric.com
Website: http://www.flanderselectric.com
Contact:
Maurice KidwellProduct: Low Voltage Motors - Medium and High Voltage Motors - DC Motors



HOUMA ARMATURE
8100 McHard Rd
Houston, TX 77053
TX
United States
Phone(s): 713-748-0702
Website: http://www.houmaarmature.com
Product: Low Voltage Motors - Medium and High Voltage Motors - DC Motors


INTEGRATED POWER SERVICES (IPS)
1500 East Main Street
LAPORTE, TX 77571
TX
United States
Phone(s): (281) 471-4611
Fax: (281) 471-3120
Email: services@ips.us
Website: http://www.ips.us/houston
Product: Low Voltage Motors - Medium and High Voltage Motors - DC Motors



SAN ANTONIO ARMATURE WORKS
1015 N Colorado St
SAN ANTONIO, TX 78207
TX
United States
Phone(s): 210-227-0291
Fax: 210-223-9904
Email: stevestaglik@saarmature.com
Website: http://www.saarmature.com
Contact:
Steve StaglikProduct: Low Voltage Motors - Medium and High Voltage Motors - DC Motors



SHANEDA ELECTRIC
2500 Pearl Rd
ODESSA, TX 79761
TX
United States
Phone(s): 432-333-7083
Fax: 432-333-3407
Email: pholder@nwol.net
Website: http://www.shaneda.com
Contact:
Phil HolderProduct: Low Voltage Motors - Medium and High Voltage Motors - DC Motors

As an alternate, searches on the term "WEG Motor Electromechanical Brake Solonoid Repair" brought
up a few prospects.

Boucher
11-08-2012, 11:22 PM
EddyCurr, Thanks a lot for those locations. I had tried to use the WEG site and not been able to. Will call the people in San Antonio tomorrow and see if they can help me. Again thanks!

gvasale
11-09-2012, 09:38 AM
I guess wrt 220v brake, the machine as disigned for 220 three phase. I don't recall and 110v motors on 3 phase, if you were thinking in that direction. You might think about soaking the coil in acetone or MEK to try & dissolve the potting material.

EddyCurr
11-09-2012, 09:47 AM
It may turn out that their direct involvement (replacement/repair) may
prove to be prohibitively expensive, but one doesn't know unless ...

OTOH, connecting with the 'right' person could result in information that
enables self-repair along the lines discussed earlier in the thread. (By
example, recently Clausing was very helpful to me regarding information
for fabricating discontinued parts.)

Boucher
11-09-2012, 09:40 PM
Well the motor is at SAN ANTONIO ARMATURE WORKS. Cost and schedule are unknown. Hope that I donít have to take out a loan to get it back. My backside is tired after 6 hours in heavy traffic today. I appreciate every ones help. I have learned a lot. I dread trying to stuff this back in. It was difficult getting it out.

MaxHeadRoom
11-09-2012, 10:27 PM
I guess wrt 220v brake, the machine as disigned for 220 three phase. I don't recall and 110v motors on 3 phase, if you were thinking in that direction. You might think about soaking the coil in acetone or MEK to try & dissolve the potting material.

See post #15, it is fed off of the control transformer, no word yet if the secondary is 120 or 220?
http://bbs.homeshopmachinist.net/threads/56529-Rotary-Phase-Generator-Questions?p=806509#post806509
Max.