Increase external overload protection is to prevent motor burned effective means, such as thermalrelay protection.
增加外部过载保护是防止电机烧毁的有效手段，如热继电器保护。
2
Contactor can be easily retro-fitting auxiliary contact group, and appropriate combination of thermalrelay to protect the load that may have been circuits.
接触器还可方便地加装辅助触头组，和适当的热继电器组合，保护可能发生过负载的电路之用。
3
So developing the research on the reliability test technology of thermal overload relay has great signifi.