The permanent magnet actuator(PMA) is a new kind of mechanism which can hold the breaker at opening and closing positions through permanent magnet and it can be controlled with electronics as well.

• 永磁机构是一种通过永磁保持、电子控制的新型操动机构，具有高可靠、免维护和智能化的优点，成为真空断路器操动机构发展的热点，其性能的优劣严重影响断路器的开断性能。