(1) motor winding circuit

    When the motor winding phase winding open circuit, or a parallel branch in a branch circuit, will result in unbalanced three-phase current, the motor from overheating.

   (2) motor winding short-circuit

    When the motor winding short-circuit fault, short-circuit the winding copper loss is much greater than the normal operating current increases, causing the windings to overheat and even burn.

   (3) Motor connection error

    When the wrong motor connected in star delta connection, the motor is still with full load current flowing through the stator windings exceed the rated current, and even lead to the motor self-parking, stop a little longer and not turn off the power, not only seriously winding overheating will be burned.

    When the star-connected motor wrong then into a triangle will windings and core overheating, severe burned wiring.

   (4) motor windings connected in reverse

    When a coil, the coil group or one phase winding connected in reverse, can lead to serious imbalance in three-phase current of the winding overheating.

   (5) Mechanical failure of the motor

    When the motor shaft bending, poor assembly, bearing defective, etc., the average motor current will increase, increase in copper loss and mechanical friction losses, so that overheating of the motor.