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1.故障现象某水电厂一台 V1/40-1型空气压缩机运行时声音异常,后因其润滑油油压过低保护动作而停机。停机后,值班人员操作试机时,电动机却不转,故切除电源。经现场检查发现,该压缩机的电动机(型号 JO_2—72—6,380V、44.2A、22kW、△接法)接线盒外电缆芯线表面有一层黑灰,判断故障可能发生在接线盒内。打开接线盒,看到中间 B 相接线端子上的电缆芯线已熔化断线,其压紧螺母与螺栓烧结在一起,固定胶木底板的螺栓周围严重烧焦炭化。经用兆欧表摇测绝缘电阻,接线端子对地绝缘为零,但电动机绕组绝缘仍正常。2.故障原因分析该电动机引线电缆 VLV-3×10三根铝芯电缆芯线在接线盒内比较拥挤,中间 B 相芯线短而且紧,除承担较大的应力外,还要
1. Symptom A hydropower plant, a V1 / 40-1 air compressor sound abnormal operation, because of its oil pressure is too low protection action downtime. After shutting down, the duty operator operates the test machine, the motor does not turn, so cut off the power. The site inspection found that the compressor motor (model JO_2-72-6,380V, 44.2A, 22kW, △ connection) outside the junction box cable core surface has a layer of black and gray, determine the fault may occur in the junction box. Open the junction box, see the middle of the phase B cable terminal block has melted wire break, the compression nut and the bolt together, fixed bakelite floor around the bolts of severe scorch charring. Measured by megohmmeter insulation resistance, terminal insulation to zero, but the motor winding insulation is still normal. 2. Fault reason analysis The motor lead cable VLV-3 × 10 three aluminum cable core wire in the junction box is more crowded, the middle phase B short and tight core, in addition to bear a greater stress, but also