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

Electrical
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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.

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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.

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The closing bounce problem in high voltage vacuum circuit breakers (VCBs) occurs when the moving contact bounces upon impact with the fixed contact during the closing operation. This repeated bouncing can lead to arc re-ignition, contact wear, temperature rise, and even reduced dielectric strength, affecting the long-term reliability of the breaker.

At Degatech Electric, we address this issue through advanced mechanical design, optimized damping systems, and precision control mechanisms to ensure smooth and stable contact performance.

:gear: 1. Understanding the Cause of Closing Bounce

Closing bounce mainly results from:

  • High kinetic energy of the moving contact during closing
  • Insufficient damping or cushioning in the operating mechanism
  • Elastic deformation in linkages or springs
  • Improper alignment between moving and fixed contacts

These mechanical imbalances cause the moving contact to rebound after initial closure, momentarily breaking contact pressure.

:wrench: 2. Engineering Solutions

a. Optimized Spring and Mechanism Design

By carefully tuning the closing spring force and mechanical linkage geometry, manufacturers can ensure that sufficient contact pressure is applied without excessive impact energy. At Degatech Electric, our design engineers use finite element analysis (FEA) to achieve the ideal spring stiffness and motion profile, minimizing contact bounce.

b. Improved Damping System

Adding shock absorbers or damping materials in the operating mechanism absorbs excess kinetic energy, preventing mechanical rebound. Degatech employs integrated damping structures to reduce impact velocity and stabilize the contact motion.

c. Enhanced Contact Material and Structure

Using high-strength, high-elasticity contact materials with optimized surface geometry helps maintain uniform contact pressure. Our vacuum interrupters are engineered to ensure low arc energy and minimal erosion during closing.

d. Precision Manufacturing and Assembly

Mechanical tolerances play a major role. Degatech Electric maintains strict precision control during production — every component of our VCBs is tested for alignment, spring consistency, and closing speed to eliminate bounce issues.

:zap: 3. Testing and Quality Assurance

Advanced dynamic contact testing and high-speed motion analysis are used to verify closing performance. At Degatech, each vacuum circuit breaker undergoes comprehensive mechanical endurance tests to ensure smooth closing action, no visible contact rebound, and consistent dielectric performance over its service life.

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:white_check_mark: 4. Conclusion

Solving the closing bounce issue in high voltage VCBs requires a combination of mechanical optimization, damping control, and precision manufacturing. Through continuous research and innovation, Degatech Electric delivers reliable, long-lasting, and eco-friendly vacuum circuit breakers that operate safely under demanding conditions.

Learn more from a professional vacuum circuit breaker manufacturer committed to high-quality and sustainable power solutions.