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-   -   3PH 480V motor wiring and tripping on overload (https://www.askmehelpdesk.com/showthread.php?t=354270)

  • May 15, 2009, 12:47 PM
    NEWBIE TINMAN
    3PH 480V motor wiring and tripping on overload
    :confused:REPLACED EXISTING DAYTON MOTOR WITH EXACT MODEL NUMBER. 3PH 480V
    WIRED IT EXACTLY AS SHOWN ON NAME PLATE. KEEP TRIPPNG BREAKER. NAME PLATE INDICATES 1.9AMP FULL LOAD. I MEASURE 3.4AMP. MOTOR IS USED FOR BELT DRIVEN
    BLOWER. IREMOVE BELT AND I HAVE 1.4AMP READING IS THIS NORMAL(NO LOAD) READING
    .
  • May 15, 2009, 11:15 PM
    hvac1000
    Check all 3 legs of the circuit for exact voltage readings. Low voltage on one or more legs will cause the problem you are having.
  • May 16, 2009, 04:40 AM
    tkrussell

    Could be possible that rotation is incorrect. This would cause the FLA to increase beyond the nameplate FLA, and cause the overload to trip.

    If so, just swap any two leads of the 3 phase wiring.

    Or the pulley or fan that the belt is driving could be stiff, bound, or otherwise too tight, bad bearing, for example, which would cause the FLA to be too high.
  • May 16, 2009, 05:19 AM
    hvac1000
    On a belt driven blower a reverse rotation will cause less of a load since it will not be moving the air since the wheel will not be scooping up the air. Now a adjustable pully can cause problems if not adjusted properly.
  • May 16, 2009, 06:17 AM
    jerro

    Are you tripping the main breaker for the ac unit or tripping the overlaod heaters. This makes a difference as to what to look for. What was the reason for changing the motor?

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