电动机石墨轴承断裂分析

电动机经修理后进行试验，发现信号指示灯不亮。测量发现黄线和红线断路，分解检查发现C相电路中温度保险丝熔断，石墨轴承断裂损坏。电动机内与石墨轴承接触的相关零件进行外观观察、体视检查、组织检查、硬度测试，对石墨轴承的断口进行微观分析，以查明石墨轴承断裂原因。结果表明:电动机石墨轴承受热损伤后产生过载断裂；石墨轴承端面与转子钢制端面工作中相互摩擦导致热损伤；建议控制电动机石墨轴承与转子端面的安装间隙，以减小相互摩擦导致的热损伤。

Failure Analysis of Graphite Bearing in Electromotor

When an electromotor was tested after repair, the indicator light couldn't work effectively. It was found that the yellow line and red line were broken. And then it was found that the temperature fuse in the C phase circuit had been melted and broken and the graphic bearing had fractured. To find out the failure cause of the graphite bearing, macro and micro observation, metallographic examination and hardness test were carried out. The results show that the fracture mode of the graphite bearing is overload fracture after heat damage. The heat damage was caused by the friction between the graphite bearing end surface and the rotor end surface. Accordingly, it is suggested that the installation clearance between graphite bearing end surface and rotor end surface should be controlled to reduce friction and heat damage.