Cleaning out an electric motor?

[T i m]

Hi all,

I just picked up an old floor standing pillar drill and the (synchronous?) motor pulley has been rubbing on the motor frame and showered the motor with fine aluminium filings. Plus there is some general oil, dust and dirt visible in the ends so I wondered if there was a safe way to flush it through (without having to strip it down ideally)?

I don't think this is the original motor, FWIW.

I'm happy to run some suitable fluid though (white spirit etc?) it can follow that with an airline and the bearings have those little spring-loaded ball bearing oiling points so I can re-oil them afterwards.

Thanks in advance ...

Cheers, T i m

[The Natural Philosopher]

parafin or diesel is pretty safe, followed by alcohol to de grease it

[T i m]

Thanks for that. I was reading that you have to be careful re non-solvent proof windings (shellac / varnish) and oven drying if you use anything water based.

It's not particularly greasy so think something like paraffin should be sufficient for that facet (unless you are suggesting I *should* de grease it of the paraffin)?

Cheers, T i m

[T i m]

Googling some more I found this:

And post 3 suggests paraffin contains a lot of water? Maybe it isn't the same issue as plain water re motor windings.

Cheers, T i m

[Peter Parry]

You would be better dismantling it and using a brush and air line to clean as much gung out as possible. Induction motors are not usually difficult to disassemble.

If you must try to clean it intact the safest solvent is Isopropanol (Isopropyl alcohol (IPA)). It is unlikely to affect the varnish on the windings. Using a new container of IPA it has the added advantage of drying the motor out as well.

[harry]

+1 Metal particles are very bad news in motor windings. Before you take off the end caps, score a mark across the joints so they go back in exactly the same position. The bearings bed in, putting them back exactly as before means this doesn't have to happen again. There may be a centrifugal switch. Check this out, clean contacts and a drop of oil.

[T i m]

Thanks, I'll look at that tomorrow.

Noted.

Another problem I've since found is the motor (not the correct one for the drill but does or has 'worked') is mounted onto it's bracket using two rubber axial ring / bushes, one each end. I'm not sure if these bushes are supposed to be bonded to any of the parts because there doesn't seem to be anything stopping the motor rotating? I could probably turn or print some rigid 'bushes' and just rubber mount the motor to the drill, if such a thing is even required (but that's another story). ;-)

Cheers, T i m

[Brian-Gaff]

Hmm, I think this brought back memories of the old early video machines from Phillips, with two synchronous motors slowed down by hysteresis brakes. The much got between the rotor and the inside of the chunk with the windings and seized them, No option but to take them apart and clean them. Amazing machines those, you could keep your dinner warm on them. Brian

[T i m]

Yes and like this old motor of mine, they were made in the days when you could take stuff apart without breaking off one way tabs or having to drill out rivets etc.

The motor is now stripped down and I've brushed out the stator and rotor and will blow them out in a while. I'm about to de-grease the insides of the end casings / bearings and will ensure you can get oil in though the oiler holes before I re-lube it and put it back together.

There looks like there are two largish tapped holes in the stator frame that might take a traditional mounting bracket so I might fabricate something to suit, rather than trying to continue with the existing effort (rubber mounting rings on each end that seem to have delaminated from the rubber).

I've cleaned out the centrifugal actuator and will re-oil it after it's been blown dry but as it only actions as you start and stop the motor, it shouldn't need much in the way of lube, as long as it stays in place.

Cheers, T i m