Safety Concerns About Old Electric Motor.

pgmrdan said:
It would take more than 25 cans of contact cleaner and many hours of scrubbing. I would have pitched it before trying that. I'm not joking when I say this thing is covered inside with black gunk. The layer on the outside was probably close to 1/10th of an inch thick.

Some guys do this with a pressure washer or take them to a car wash.
Click to expand...


The "black gunk" is most probably old bearing grease.

• Do your bearings have zerk fittings? If so, then the motor probably received yearly applications of grease with the old grease being displaced onto the motor windings.

• If there are no grease fittings, then as older grease oxidizes it can sometimes work its way out of the bearing and (once again) work its way onto the armature. This means the bearings are now running dry.

I would highly suggest 2 courses of action...

1) Wash the beast. If the motor is to "burn up" it will more than likely be to an inability to cool itself rather than "old wiring". Note that solvents will merely move the "gunk" around. To remove grease one needs a detergent action, best found in hot soapy water. Obviously, all the water should be allowed to evaporate before placing the unit back in service.

2) Replace the older 'open' ball bearings with modern 'double sealed' bearings. Typically, modern bearings are loaded with a synthetic grease that will not oxidize and will therefore not require maintenance for many decades. The seals will also insure that the inside of the motor stays clean to promote cooling.

:encourage:
 
Liquid electrical tape is great for fixing old wiring in motors.
 
I like old motors. You can also cover old wires with heat shrink tubing if you are concerned about the insulation.
 
Used brake cleaner to wash out the gunk before never noticed any deterioration of any windings. Use mean green and dry the motor in the wifes oven when she isn't looking. Used red motor varnish that comes in a rattle can to dress up the windings. Customers though you had worked miracles refreshing there irreplaceable motors. Generally a good cleaning will do the trick. Just look for bad insulation like clueless says.
 
Brake cleaner is strong, I would use something more mild like mineral spirits or white gas
You don't want to soften the insulation on the wire
Mark
 
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