A vacuum circuit-breaker with permanent magnetic actuator for frequent operations

Vacuum circuit-breakers have obtained a high level of performance, reliability and safety. This is mostly owed to the advantages of current interruption in vacuum. However, the design of the mechanical drive, which has already been applied e.g. in minimum oil-breakers, has hardly been changed. With the introduction of an actuator with permanent magnetic limit positions and electro-magnetically controlled motion, the next generation of vacuum circuit-breakers is launched promising an increase in reliability and endurance. In addition, the vacuum interrupter is embedded in epoxy resin in order to achieve an optimum dielectric strength, to protect the interrupter from external influences and to secure a stable support. The experience with frequent operations reaching 100000 CO is promising. Besides the explanation of the physical background and function, special emphasis is laid on the interaction of actuator and vacuum interrupter during opening.