桥式起重机是工矿企业中应用十分广泛的一种起重机械。我厂输煤系统现有多台桥式起重机,工作量很大,使用频繁。桥式起重机电力拖动系统多采用绕线型交流异步电动机。电动机转子回路内串入多段外接电阻调速,并采用凸轮控制器、继电器和接触器控制。桥式起重机存在故障率高、维修工作量大,给正常生产、日常维护带来许多不便等问 Bridge crane industrial and mining enterprises in the application of a very wide range of lifting machinery. Our existing coal handling system multi-bridge crane, heavy workload, frequent use. Bridge crane electric drive system uses more winding AC induction motor. Motor rotor loop series multi-stage external resistance speed control, and the use of cam controller, relay and contactor control. The high failure rate of overhead traveling crane, heavy maintenance workload, to the normal production, routine maintenance and so bring a lot of inconvenience