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What is circuit breaker contacts?

Sep 30, 2018

After receiving the action command, the circuit breaker operating mechanism must be accurate and reliable, and the action time and the closing speed meet the nominal technical specifications of the circuit breaker.


It is easier to open and close the circuit breaker contacts  when the grid is operating normally. However, when the circuit with pre-short-circuit fault is closed, the circuit breaker may not be in place due to excessive electric power, which may cause serious burns to the contact. Therefore, the operating mechanism must have sufficient operation work to overcome the electric power. In order to enable the circuit breaker to complete the closing task quickly and reliably.


Due to the short duration of the closing command during the closing process, and the operating force of the operating mechanism is only provided within a short period of time, there must be a portion of the operating mechanism that is kept closed to ensure that the closing command and operating force disappear. After that, the circuit breaker remains in the closed position.


When the circuit breaker is closed with a faulty circuit, the circuit breaker will automatically open. If the closing command has not been released at this time, the circuit breaker will be closed again after opening, and then it will open again. In this way, the circuit breaker may close and break the short circuit fault multiple times. This phenomenon is called "Jumping". When the phenomenon of "Jumping" Occurs, the circuit breaker auxiliary contacts are severely burned. Therefore, the circuit breaker must have an anti-jump function, generally in both mechanical and electrical ways.


The opening and closing speed of the circuit breaker contacts is very fast. When the splitting and closing operations are performed, the high-speed moving contact should be stopped smoothly to reduce the damage of the huge impact force during braking. It is necessary to install a buffer device on the operating mechanism.

Circuit Breaker Contacts