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Thread: drying a motor

  1. #31
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    Quote Originally Posted by HavinaGo View Post
    Thanks for the corrections. always thought care was needed around the enamel but obviously tougher than I thought.

    Phil's clean up looks good.
    Hi David,
    Yes, it's tough stuff, to the point of being very hard to remove. I'm used to winding coils and stripping the enamel is a real pain. There are different coatings now-a-days that allow you to solder through the coating, but those types are generally not used in motor applications. The motor wire often uses a high temperature type of enamel. polyimide? something...

    Anyway, when all is said and done, it doesn't hurt to be cautious.

    Ray

  2. #32
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    Been following this thread with acute interest as well. It prompted me to pull apart a 1/2HP 'period' motor I have set aside for the 'new' Waldown I got from Azzrock.
    When I tried to run it, it immediately tripped the RCD in the shed. Must be dirt or wasp nests inside it....
    Anyway, once apart, I spotted the culprit: a squashed wire that had chafed through. Phew. Always glad to find tangible reasins for mysterious faults.
    Anyway, tonight I cleaned the outside of all parts and tomorrow will follow Phil's example and clean the inside.
    Once reassembled and tested, I'll prime it ready for two-pack 'Waldown' blue.
    Shouldn;t be too long Ray...
    Cheers, Joe
    retired - less energy, more time to contemplate projects and more shed time....

  3. #33
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    Old Electrician here. I became "old" on Sunday!
    Washing Electric Motors.
    Wash - use a detergent to get the grease off. Pressure spraying, especially high pressure can force the "muck" (read metal shavings, swarf, etc.) into the motor, where, later, as it runs merrily along (vibrating), it may well cause abrassion to the windings insulation. Read expensive here! So watch the way you clean it. The sort of stuff we used to use in the good old days is now banned, but thats OK, as my cancer is in remission! Finish washing with clean water. The plan is not to damage the winding insulation in the washing process.
    Drying Motors.
    Low voltage connected to the motor works well. If you have a Variac (variable voltage auto transformer) thats easy. If you don't, try connecting the motor across a battery charger, and adjust the amps to the Motor Nameplate "amps" or less. The idea is that the low voltage current through the windings will heat them up - from the "inside" so to speak, without stressing the insulation - because the voltage applied is much lower than the winding insulation rating - even wet. If the rotating part of the motor is installed, it will make a growling kind of noise with voltage applied. This is OK. Easier if the rotor is removed, but not essential. Hard to do on big motors!
    Windings, Centrifugal Switches, Start Capacitors on Single Phase Motors.
    Some (most) single phase motors have a centrifugal switch which opens the "Start Winding" once the motor has started running. Some have a capacitor in series with the "Start Winding." To dry the "Start Winding," this winding needs to be connected to the low voltage supply. ie. the centrifugal switch should be closed (normal when the motor is stationary), and the capacitor needs to be shorted out.
    All the above is good in winter time, but at the moment, the best solution is to leave it out in the warm sun for several days, and test the motor insulation with a "Megger" when finished.
    I think that all, but I can't remember!
    Regards,
    Alan

  4. #34
    Join Date
    Sep 2011
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    Quote Originally Posted by RayG View Post
    Hi Phil,

    I sometimes forget to switch off power to the compressor, and with a slow leak, it cranks up at 3 in the morning... then it's my wife complaining, and I have to get up and switch it off.

    Ray
    I know what you mean Ray.
    I get up to my compressor more than I ever got up for my kids
    I, like Dean do the same with the light which shines through the window at the guy behind me. I'm surprised he tolerates me at all

    Quote Originally Posted by A J in WA View Post
    Old Electrician here. I became "old" on Sunday!
    Washing Electric Motors.
    Wash - use a detergent to get the grease off. Pressure spraying, especially high pressure can force the "muck" (read metal shavings, swarf, etc.) into the motor, where, later, as it runs merrily along (vibrating), it may well cause abrassion to the windings insulation. Read expensive here! So watch the way you clean it. The sort of stuff we used to use in the good old days is now banned, but thats OK, as my cancer is in remission! Finish washing with clean water. The plan is not to damage the winding insulation in the washing process.
    Drying Motors.
    Low voltage connected to the motor works well. If you have a Variac (variable voltage auto transformer) thats easy. If you don't, try connecting the motor across a battery charger, and adjust the amps to the Motor Nameplate "amps" or less. The idea is that the low voltage current through the windings will heat them up - from the "inside" so to speak, without stressing the insulation - because the voltage applied is much lower than the winding insulation rating - even wet. If the rotating part of the motor is installed, it will make a growling kind of noise with voltage applied. This is OK. Easier if the rotor is removed, but not essential. Hard to do on big motors!
    Windings, Centrifugal Switches, Start Capacitors on Single Phase Motors.
    Some (most) single phase motors have a centrifugal switch which opens the "Start Winding" once the motor has started running. Some have a capacitor in series with the "Start Winding." To dry the "Start Winding," this winding needs to be connected to the low voltage supply. ie. the centrifugal switch should be closed (normal when the motor is stationary), and the capacitor needs to be shorted out.
    All the above is good in winter time, but at the moment, the best solution is to leave it out in the warm sun for several days, and test the motor insulation with a "Megger" when finished.
    I think that all, but I can't remember!
    Regards,
    Alan
    Hi Alan,
    'Now' you tell me
    Happy Birthday for Sunday.
    When I used the degreasing gun I set the nozzle towards volume rather than pressure so it should be ok...I hope.
    We have an electrician at work so after it has had a good drying on top of the boilers (It was 52 deg in front of them yesterday and it is hotter again up top) I might get him to megger it and then I should know for sure.
    Of course I am assuming he will 'have' a megger.
    I said it before but I'll say it again."Thanks guys".
    Anything electrical to me is black magic and I really have no idea so this has been very helpful
    My shoulders dropped when I opened it up but I'm smilin' again now.

    Phil

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