(A) the supply voltage is too high

    1 when the supply voltage is too high, the motor counter electromotive force, the magnetic flux and the magnetic flux density increases. Due to the size of the iron loss and magnetic flux density is proportional to the square of the iron loss increases, resulting in overheating of the core. While the magnetic flux increases, but also increased dramatically, resulting in the excitation current component caused by the copper loss of the stator winding increases, so that overheating of the windings. Therefore, the power supply voltage exceeds the rated voltage of the motor, cause the motor to overheat.

    2, the power supply voltage is too low

   When the power supply voltage is too low, when the electromagnetic torque of the motor is kept constant, the magnetic flux is reduced, a corresponding increase in the rotor current, the power component of the stator current load increases, causing the winding copper loss increases, resulting in the set, the rotor winding overheating.

    3, the supply voltage asymmetry

    When the circuit in the power cord, fuse fuse, or the the knife starting equipment angular head burns resulting in a barrier, will result in the three-phase motor to go single-phase, two-phase windings resulting in running large current and overheating, but when we had burned.

    4, three-phase power imbalance

    When the three-phase power imbalance, will make the motor phase current imbalance, caused by overheating of the windings.

    Be seen from the above, when the motor overheating, you should first consider the reasons of power. Make sure the power aspect of problem, they go to consider other factors.

    (B) the load of the motor overheating

    The loading of the motor overheating reasons are the following:

    1, motor overload operation,

    When the equipment is not complete, the motor load power is greater than the rated power of the motor, the motor long-term overload operation (ie, a small horse-drawn carts), will cause the motor to overheat.

    2 drag the mechanical load is not working properly.

    Equipment supporting, but the drag of the mechanical load is not normal, run-time load big, sometimes small, such as thresher feed excessive, the motor overload fever.

   3, drag mechanical failure

   When being dragged mechanical failure, rotation is not flexible or jammed, will cause the motor overload caused by overheating of the motor windings.