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1.故障现象操作人员使用Ⅱ挡速度下放1台50t双梁桥式起重机吊钩时,该起重机卷扬机构发出剧烈“嗡嗡”异响。该起重机起升、下降速度备前3个挡位,其他挡位未见异响。2.工作原理该50t桥式起重机属于重载荷起重机,其卷扬机构配装功率为63kW、绕线转子三相异步电动机。该电动机外接了R1、R2、R3分段式电阻,通过改变阻值实现各挡位速度的切换。定子线圈由FCS、DCS、ZCS接触器控制,实现卷扬机构升、降控制。该起重机卷扬机构电气主回路如附图所示。该起重机卷扬机构执行起升动作时,接触器ZCS吸合,卷扬电动机受三相正序电流,电阻R1、R2、R3通过分段切换,
1. Symptom The operator using the second gear speed down a 50t double-girder overhead crane hook, the hoist mechanism issued a dramatic “buzzing” abnormal sound. The crane hoisting, descending speed of the first three gear, the other gear no abnormal sound. 2. The working principle The 50t overhead crane is a heavy load crane, the hoisting mechanism with a power of 63kW, wound rotor three-phase asynchronous motor. The motor external R1, R2, R3 segmented resistance, by changing the resistance to achieve the various gear speed switching. Stator coil by the FCS, DCS, ZCS contactor control, hoist lifting mechanism to achieve, down control. The crane winch electrical main circuit shown in the figure. When the hoisting mechanism of the crane performs a lifting operation, the contactor ZCS is pulled in and the winching motor is subjected to a three-phase positive sequence current, the resistors R1, R2 and R3 are switched by stages,