OT? old induction motor has oil saturated windings

The shiny windings at the bottom are covered in oil.

This is from a pre-1930 GE 1hp motor. I tore it down today and found that the bottom of the windings are pretty much saturated in oil. This is a plain bearing motor with oil baths/slinger rings at each end. The motor did run before I took it apart - I just wanted to clean it out and make sure there aren't any mouse nests or something.

I don't know if I should even worry about the oil on the windings. It isn't just the wires - the little steel sections of the winding core ooze oil when pressed from the side with a screwdriver.

And if I do need to get the oil out, I don't know the best way. I suppose left to my own devices I'd buy a couple cans of CRC Lectra Clean, put the stator in a plastic tub, and start spraying and wiping.

Ideas? Opinions?

metalmagpie

I agree, I'd use some sort of electrical-rated spray cleaner. Several cans. I'd try to avoid forcing dirt down further into the nooks and crannies. I'd use minimal wiping, if any. That could remove more than you want removed.

Oil is never good for a winding.

How do you know the motor is pre-1930's? That winding looks like newer, in terms of construction, than that.

I had a motor that was full of grease, literally plugged full.
I.pressure washed it with soap and hot water. Dried it for 2 days in front of the wood stove and it was fine.

Soap and water then blow dry and put it in an oven for several hours at 250 degrees F. If the windings are in good shape, then an ultrasonic cleaner works well also. Never tried it on very old windings, but we always ultrasonic clean dc armatures. Those windings don't look real old.

Suspend over a 5 gallon bucket (or cut one down shorter in height) and spray some liquid into the windings. I use Simple Green.
Then rinse with water. This method might take a while for the junk to drip clean. At the end blow out with compressed air. I've
done this on every motor that I use (the ones that I acquired used).

If I did use soap* and water, I'd insist in baking it to drive out the water. I'd use something like 190-200F for several hours....I'd keep it below the boiling point.

*Soap is a broad term....I'd certainly not use Oil of Olay or Johnson's Baby Shampoo. I might use one of the stronger 'industrial' degreasers which I classify more as a detergent than a soap. But even then, I'd prefer a dedicated electrical cleaner than cuts grease faster and rinses cleaner.

A megger is your friend here. You want the windings to show at least 1 megohm insulation resistance before applying power. If windings are wet you’ll see the megohms go down as the moisture is driven out then go back up as it dries. Once past 1 megohm the best way to dry the motor is to run it continuosly for some time. It should go up over 100 megohms when completely dried.

After cleaning that motor and drying it a varnish dip and bake would be a good idea.

When I was in the service we used to get pump motors in the repair shop that had been flooded in the JP-4 pits. They were really nasty. As others have stated, the best way to clean them is with hot soapy water. If I remember correctly we even steam cleaned a few of them. We would then replace the bearings even if they didn't need it in my opinion (your tax dollars at work). The key is baking them out. We had a big oven to do it but most anything would work. It was nothing fancy, just a big oven. 200 degrees for two days.