the rotor of hoist motor heats while windings are cool

Discussion in 'Electronics Resources' started by haji jongo, Aug 25, 2013.

  1. haji jongo

    Thread Starter New Member

    Aug 24, 2013
    hello how you doing i hope you are well like me ,i have a problem with hoist motor for over head crane,it was burn ofter rewinding we see that the rotor heats after 5 minutes while the windings are cool when operate without load and we decide to remove the gear box but still heats and the current is abutr 6 Amps for each phase what help can you do for me
  2. strantor

    AAC Fanatic!

    Oct 3, 2010
    If it's not rewound right, it won't work right. I've experienced the same thing. Motor fails; you send it in for repair/rewind, comes back, runs hot. Never runs the same after. This is when you find a new rewind shop.
    PackratKing likes this.
  3. MaxHeadRoom


    Jul 18, 2013
    I am assuming this is a standard Induction motor rotor c/w shorting bars?
    Rather than a wound rotor motor with slip rings?
    If the former, and the rotor cannot rotate for some reason it could be a couple of reasons, miss-wired/connected stator or some of the rotor shorting bars have become disconnected, although this usually causes lower current in both the rotor and stator and the rotor will fail to rotate.
    Does the rotor rotate normally?
    It is very unusual to have disconnected rotor bars on a modern motor as they are cast into the rotor.
    Older ones had copper bars with the shorting plate soldered on the end and the solder was flung off if the rotor overheated.
    Take the rotor out and examine it.
    Is the current normal for the motor?
    Either way it looks like you have a defective/misconnected motor?