Causes of Winding Short Circuit in Asynchronous Motors

The motor may be short-circuited due to overload, overvoltage, single-phase operation or poor insulation of the winding. A large circulating current will pass through the short-circuited turns, causing the coil to heat up quickly or even burn out. The reasons for the winding short circuit are:

The motor runs under overload or overvoltage for a long time, which causes the current in the winding to be too large and heat up, which accelerates the aging of the insulation, makes the insulation brittle and cracks, and loses its insulation function. Or the brittle insulation falls off due to vibration.

When repairing an electric motor, the outer insulation of the enameled wire may be damaged due to careless operation, or the insulation of the welding lead may be damaged due to high soldering iron temperature and long soldering time.

The motor that has been out of service for a long time has its insulation damp and is put into operation without being dried. Therefore, the damp insulation breaks down due to insufficient insulation strength.

The double-layer winding slots are damaged due to poor insulation between phases. The winding ends are too long and touch the end caps or the insulation is not well padded. The insulation of the connecting wires or lead wires between the coil groups of the stator winding is poor, or due to carelessness when wiring between the coil groups, one or more coil groups short-circuit themselves.