"Vacuum circuit breaker" because its arc extinguisher medium and the contact gap after arc extinguisher insulation medium are high vacuum; It has the advantages of small size, light weight, suitable for frequent operation, arc extinguision without maintenance, and is widely used in distribution network. Vacuum circuit breaker is 3 ~ 10kV, 50Hz three-phase AC system in the indoor distribution device, can be used as the protection and control of electrical equipment in industrial and mining enterprises, power plants, substations.Especially suitable for the requirements of no oil, less maintenance and frequent operation of the use of places. The circuit breaker can be configured in the middle cabinet, double cabinet and fixed cabinet as the control and protection of high voltage electrical equipment.