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我场自制了一台外跨70米的龙门吊车,用以木材装车和分堆。由于作业上要求电机能带负荷或重负荷起动,因此电机需要有较大的起动力矩,所以吊车起重用的电机和吊车车体行驶的电机都是采用JZ_2或JZR_2系列起重和冶金用三相异步电动机。这种电动机转子上也绕有三相绕组,接成星形,在正常运行时,这三相绕组通过滑环短接。若在转子绕组短接状态下起动,则在定子绕组开始通入电流而转子尚未转动时,电动机好像一台变压器在次级绕组短路的情况下运行,绕组中将有很大的电流通过。因此滑环式异步电动机起动时要在转子绕组中接入变阻器,以限制起动电流,同时用以增大起动转
My home made a gantry crane 70 meters outside the cross, for loading timber and sub-pile. As the operation requires the motor can load or heavy-duty start, so the motor needs a larger starting torque, so crane crane motor and crane body travel motor are used JZ_2 or JZR_2 series of lifting and metallurgical three-phase Induction motor. This motor rotor is also wound around the three-phase winding, connected into a star, in normal operation, the three-phase winding shorted through the slip ring. If the rotor winding is short-circuited, when the stator winding starts to pass current and the rotor is not rotating, the motor looks like a transformer running on the secondary winding short-circuited and a large current will flow through the winding. Therefore, slip ring asynchronous motor start to access the rotor winding varistor to limit the starting current, while increasing the starting turn