I. Overview ZW32M-12 type outdoor high voltage permanent magnet vacuum circuit breaker (hereinafter referred to as breaker) for the rated voltage 12kV, three-phase AC 50Hz outdoor distribution equipment. Mainly used for breaking, closing power system load current, overload current and short circuit current. For substation and industrial and mining enterprises distribution system protection and control of workplace use, and frequent operation of rural power grids. The circuit breaker has small size, light weight, anti-condensation, maintenance-free characteristics, can adapt to poor weather conditions and dirty environments. The product uses a permanent magnet type operating mechanism to operate; the permanent magnetic holding force operating mechanism provided by a permanent magnet, so that the switch remains in the open and close positions, a small number of mechanical parts, mechanical transmission chain is short, thus greatly improving the reliability of the switch and mechanical life.