Crane motor is a crane motor, is intermittent work, it is characterized by frequent start, brake or reverse, the size and direction of the load are often changed. Therefore, the motor used in the crane is different from the explosion-proof motor, which requires high mechanical strength and overload capacity to adapt to mechanical vibration or impact. To reduce inertia during starting and stopping, the rotor is made slender. The crane mainly uses the induction motor, has the squirrel cage type and the wound wire type two kinds, they are by the stator and the rotor two basic parts are composed. The rotor part of the wound rotor motor consists of a rotor core and three-phase symmetrical windings. The rotor windings are embedded in the slots of the rotor core and are connected in a star shape. The rotor winding 1 of each phase is respectively connected with three slip rings 2 of the rotating shaft through flat copper bars, and is connected with an additional resistor 4 through the slip rings. The rotor winding of winding motor is connected with additional resistance, which causes starting, overload and impact. Therefore, winding motors are widely used in cranes.
