Dissolving Stator Winding Enamel Coating

[6E5]

Hello,


For a semester project of mine I am dissecting an induction motor and simulating its specs in FEMM. I want to look at the stator winding, however, the whole complex is covered in some sort of enamel or epoxy.

What solvent would be best for this application? I was thinking about Acetone or Lacquer thinner.

[T3sl4co1l]

Methylene chloride, or heat ("Fire... and lots of it!" -- Dr. Hibbert).

Is it not sufficient to measure the wire diameter, count what turns you can see, and fill in the blanks, or just saw one in half and count by eye?

I imagine FEMM has a uniform current density attribute which would do an excellent job of simulating the overall behavior of a motor; you could even skip the stator altogether and use B-field source directly on the faces.

Tim

[jeremy]

Only chemical that I've heard works on these things is hydrofluoric acid. But that will destroy *everything* and is about as safe as riding your bike in the middle of the highway.

[calexanian]

I might try putting it in some MEK or acetone in lets cay a clean paint can. Seal it p, and check it after a day or so. It may destroy it, but it may also dissolve it. It all depends of the varnish used. Some will soften, some wont. If you need an example of motor parts many motor rewinding companies exist and if you call a local one I am sure they can help you out.

[johansen]

just heat it up in a pot of boiling water and everything should just about fall apart.

you'll discover they are far from ideal.
I wouldn't even bother with this ordeal on anything less than 5 HP, the motors are simply too inefficient. below 1/4th to 1/3rd hp and you can't even generate enough electricity from them to cover their own losses, a 1/2hp 4pole motor might be 50% efficient as a generator back feeding the grid

as a general rule, no load current is 1/3rd full load current.
most small induction motors i've taken apart run the core at about 1.8T.. which means they start to saturate the core at 2/3rds nominal nameplate "volts"

[G7PSK]

Find a re-winder shop and ask what they use as they are taking motors apart all day.

[SeanB]

Rewinders cook the motor windings off in an oven, then strip off the old windings and rewind with the same wire and new insulating material. If the windings are not varnished they cut the ends off and punch out the windings in the slot. Only on a low voltage motor will they count the turns, as with 300 turns plus a few more or less ( so long as all windings put back are the same number) has little effect on performance.

Scrap copper is kept in a safe till they take it to the yard as a block for sale. $6 per kilo makes it valuable.