The cause of the motor starting bad? What are those?

When start the switch after the closing of the motor,the motor not only noise,rotating or cannot achieve normal speed,then for motor starting,shall immediately stop the fault motor,check the reason,the magnet prices main reason:(1) mechanical damage or stuck;www.dongfeng-motor.com (2) the rotor circuit there may be offline or poor contact. Squirrel-cage motor generator stator end ring and copper bar connection damage; Winding type motor rotor ac motor wind generator rheostat circuit disconnect,the connection of the cable damage,there was something wrong with brush device,fuses and the slip ring connection damage and so on.(3) a phase stator loop break line;(4) of the stator circuit wiring errors.