cleaning motors in service 1

[yulinios]

Hi There

I'm working in a coal power plant, we have a lot of dusty places, I would like to know what is the best way to clean the motors in service?

Bye

 

[busbar]

thread237-18853 By “in servce,” one needs to carefully differentiate procedures for energized, assembled equipment from those that are not.

 

[corrosivo]

yulinios
In general there is no best way to clean a motor in service, and this action must be done as a last resource.
Because you do not have full access to the windings with the motor end covers in place it will be very difficult to do a complete winding cleaning.
What will happen is that the carbon dirt and used grease/oil will be dislodged from one place and transported by the solvent to an inaccesible crevices in the winding doing more harm to the insulation. Also is not a good idea to work with a spray nozzle around rotating machinery!

There are several electric motor cleaners brands, these are "safe" solvents, nonflammable, nontoxic, nonconductive, ozone safe, insulation safe, etc. Do not use other type of fluids.

Bear in mind that when you are spaying these fluids; the atmosphere in the sorroundings might become saturated with the vapors forcing the people around to evacuate the premises, also these vapors are more heavy than the air so they will collect in the low areas such as basements etc. displacing the air and filling the room with a "safe" suffocating vapor this can be very dangerous. Adecuate ventilation is a must to exhaust the vapors to outside.
It will be useful to take insulation readings before and after the job to verify if there is an inprovement or if something went wrong.
Remember, when these fluids are evaporating from the surfaces they will cool the these surfaces causing condensation in the windings. Be careful not to degrease the motor bearings. Hope this helps.

 

[candu6]

What kind of motor (totally enclosed, open)? You can just steam clean small Totally enclosed motors, stay away form the bearings.

 

[TestBeforeTouch]

You may want to consider dry ice blasting, but I do not think it should be applied to an energized machine. It works very well and leaves no residue other than the dirt that is already in the machine. Try the link

http://www.cryosonic-usa.com/Videos.htm

 

[motorman]

Back in the “old” days, we would spray freon into the air intake to dislodge dirt and dissolve oil. Had to do this several times when the upper oil pot on a vertical machine would get over filled. I doubt you would be allowed to do such a thing today.

 

[electricpete]

Hey motorman. You're saying if we for some reason wicking gets started on a vertical motor upper bearing, we may be able to stop it by spraying an oil solvent into the cooling air? Interesting concept. Would it perhaps make more sense to spray it more directly into the upper reservoir breather? I would tend to think it would be more effective since airflowpath would likely be in through the breather, past the standpipe/shaft gap, into the rotor suction. And I would tend to think it would be perhaps slightly less risky. Less concerned about minor contamination of the oil pot than about getting conductive or reactive contaminants directly into my windings. Can you provide any more info?

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[motorman]

Ep,

I was referring to an instance where a motor user – or *gulp* even a service engineer – would put too much oil in the upper oil pot, the oil would run over the standpipe and onto the windings and rotor. We would clean the oil up by squirting freon , which was applied from a hand pumped bug sprayer, into the air intakes while the motor was running. Remove any filters first of course! Same technique used to clean horizontal machines. Came in handy when dirt build-up on the rotor would through it out of balance causing high vibration. Just be sure to stand back away from the exhaust!

I like being accused of coming up with clever concepts but never used this to stop “wicking”. I am not even sure I know what wicking is. Are you referring to a nuisance type leaking of oil coming from a vent?

 

[electricpete]

Wicking is exactly what you said. Once the oil pot overflows once, it continues to lose oil into the motor even after you have reduced the level (as indicated by consumption from the constant level oiler). Will continue to lose oil until you clean the motor. I picture that once the oil has created a path up the outer edge of the standpipe, it keeps "crawling" up and over that edge... similar to the way liquid can crawl upwards within a wick. Sorry for the vague terminology... that's what our motor shop guy calls it and I latched onto that term.

I have two motors doing it right now. I could try the freon. Large chance of a minor savings in not having to remove the motor for cleaning. Small chance of major perturbation if the winding goes poof. Hmmm.

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