Countermeasures For Heating Of Switch Cabinet Contacts

1. Correctly measure the circuit resistance of the switch cabinet
Since the heating failure of the switch cabinet equipment is mostly caused by poor Insulation Contact Box contact, the DC contact resistance of the circuit breaker is measured regularly during maintenance and repair. Because the spring will heat up and anneal when passing a large current, it is easy to cause the spring to break. Therefore, when measuring the circuit contact resistance of the vacuum circuit breaker, the current clamp is not allowed to be clamped on the spring. The contact surface between the measuring clamp and the contact finger is small, which is very easy to cause inaccurate measurement data. Therefore, a special contact finger connector can be made. The clamp is connected to the connector during measurement to reduce measurement errors. After the contact resistance exceeds the standard, it should be handled in time.
2.2 Material requirements for contacts and springs
The material of the replaced parts needs to be checked. Check the spring with a magnet to ensure that the replaced spring is a non-magnetic material. Check whether the tension of the spring meets the use requirements, replace the aging and discolored spring in time, and consider replacing the spring with a higher spring force for the heating caused by the spring tightening force. If the fixing torque reaches the standard, the moving contact does not heat up but the static contact heats up, the main reason is that the static contact and the busbar are in poor contact, the copper quality of the busbar and the static contact does not meet the requirements, and the current carrying capacity of the busbar and the static contact is small. It is necessary to replace qualified busbars and static contacts.