How to solve the issue of the Closing Bounce problem in High Voltage Vacuum Circuit Breakers (VCB)?

Closing bounce is a common problem when using high-voltage vacuum circuit breakers, thus determining how to effectively limit the frequency of the closing bounce has turn into a criterion for measuring circuit breaker quality.

Based on years of knowledge & experience, we have developed a set of solutions to this problem.

Risk Factors

1). Risk of high-voltage vacuum circuit breaker (VCB) Closure Bounce

Closing bounce is a key mechanical property for HV vacuum circuit breakers. In the closing bounce process, the contact’s opening distance is small, and the arc does not extinguish, resulting in increased electrical wear of the contacts and affecting the electrical life of the arc extinguishing chamber.

However, because of its short existence period of time, it is much shorter than that of the arc burning time in the closing process. The main risk of bounce within a particular range is that it accelerated the degradation of the arc extinguisher contacts, resulting in a shorter electrical life of arc extinguisher.

2). Handling the closing bounce of a High-Voltage Vacuum Circuit Breaker

During the closing process, due to the inelastic collision of the moving and static contacts, the bounce value is connected to numerous factors, including the elastic force of

  • The contact spring,
  • The closing speed,
  • The opening distance, &
  • The contact material of the vacuum circuit breaker.

The vacuum circuit breaker’s closure bounce time is affected by the quality of debugging as well as the machining accuracy of parts such as the

  • Aluminum support,
  • Arc extinguishing chamber,
  • Shaft pin, &
  • Commutator.

Mitigation Techniques to reduce Closing Bounce

The following steps are commonly done to reduce the closing bounce to the appropriate range:

  • Improve accessory processing accuracy, match the aluminum support & the shaft & the commutator & the steel pin, & reduce the gap.
  • Strengthen and enhance assembly quality control. During the vacuum circuit breaker assembly process, pay attention to the reasonable installation, so that the vacuum interrupter is not subjected to additional stress. Adjust the position of guide tube to ensure that the movable contact of the interrupter proceed trajectory, on the axis of interrupter, the movable contact of vacuum interrupter may move freely without jamming.
  • Appropriately increase the pre-load of the contact overtravel spring.

The high voltage vacuum circuit breaker bounce problem can be efficiently resolved by implementing the above mentioned techniques to control the bounce time.