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Thread: mike robinson

  1. #1
    Join Date
    Aug 2008
    Posts
    322

    mike robinson

    Helo everyone I work for a large university. WE have a central aircondition plant that makes ice off peak demand it is run by semins. The problem is I have to take care of everything outside the plant this means all of the buildings that this plant provides aircondition. Now down to the problem in our new student union building which is barely out of warranty Ihave lost a 20 hp. 480/volt 3ph blower moter this makes two of the in 3 months today when I discovered it the trane air handler was covered with condensation inside and out the motor does not check to ground but when you turn on the drive it trips out the drive breaker. My queston is this motor designed to run inside this air handler with water dripping everwhere even the motor was wet. Any advice would greatly appreacited



    lowtec.

  2. #2
    Join Date
    Apr 2004
    Location
    Charlotte, NC
    Posts
    648
    Most likely, but you will need to check the amperage rating to see if it is drawing too much current. There are many reasons as to why this is possibly causing the breaker to trip. If it does not read to ground, it may be internally shorted and you can check each winding individually to find out. Good luck.
    "Fighting Ignorance since 1973 (It’s taking longer than we thought)." The Straight Dope.

  3. #3
    Join Date
    Apr 2006
    Location
    Motel 6.5
    Posts
    148
    Are you getting Earth Faults on the drive? Is condensation being pulled off the coil and getting on the motor? If so, check for plugged filters, dirty coils, and closed dampers. You know, anything that would cause an abnormal pressure drop accross the coil. What is your entering and leaving water temps? Motor meg ok? Please don't meg with the motor connected to the drive,this is bad. Has this helped?

  4. #4
    Join Date
    Nov 2002
    Location
    NJ - WORK IN NYC AREA
    Posts
    1,460

    Hmm

    Mike,
    I don't beleive there should be water all over the motor?? If this is the case, the motor would have to be all sealed and rated for high moisture conditions. If the motor has openings for ventilation, it's air cooled. No water should be on it.
    As LIP stated above water is probably being pulled off the coil. This is known as "carry over." You may be moving too much air?

    I don't know much about your vsd, but it may sense a a problem with the windings due to the high moisture. Maybe a minor ground when motor starts to turn over, then it trips?

    I'm sure some of the other guys here on the site may know more about vsd's than I do.
    Last edited by mrhvacmechanic; 09-11-2008 at 10:33 PM. Reason: addition
    "My hands are for sale"

  5. #5
    Join Date
    Oct 2006
    Posts
    15
    I agree the motor should be dry or sealed and rated for wet locations. If you dry it will it run?

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