地铁车辆司机室送风单元常见电气故障及对策分析

Common electrical failures and countermeasures of air supply unit in metro vehicle cab

测试地铁车辆司机室送风单元电气故障件,分析故障原因,并提出相应对策。结果表明:空气断路器合闸时,变压器原边侧磁通量瞬变产生励磁电流从而导致故障发生;变压器的损坏多数是由于继电器触点粘连导致,需要注意变压器短路以防绝缘纸烧损;电机热继电器的整定值设定应将负载波动和电源波动考虑在内,减少保护故障的发生;中间继电器自身的灭弧能力对场景应用尤为关键;转换开关控制中间继电器切换时,触点间隔应大于继电器的切换时间。最后对送风单元中的空气断路器、电机热继电器、变压器、中间继电器、转换开关的选型设计要点进行总结。

By testing the electrical failures of the air supply unit in metro vehicle cab,the causes of failures are analyzed,and the countermeasures are put forward.The results show that when the air breaker is closed,the magnetic flux transient on the primary side of the transformer generates excitation current,which leads to the failures.Most of the damage of transformers is caused by adhesion of relay contacts,and attention should be paid to the short circuit of the transformer to prevent the burning of insulating paper.The setting value of the motor thermal relay should take into account the load fluctuation and power fluctuation to reduce the occurrence of protection failure.The arc extinguishing ability of the intermediate relay itself is particularly critical for scene app-lications.When the transfer switch controls the switching of the intermediate relay,the contact interval should be greater than the switching time of the relay.Finally,the key points of the selection design of air breakers,motor thermal relays,transformers,intermediate relays and transfer switches in the air supply unit are summarized.