YEQ1 Series Dual Power Automatic Transfer Switches(follow brief as Setting) is made up of the mechanism and automatic controller two large parts, it mainly matches with the MM1 series moulded case circuit breaker, suits for AC50Hz, rated working voltage 400V and under dual power supply system. The setting conforms to IEC947-6(1998) Auto connect switch over devise' standard, with electric interlocking and mechanical interlocking double protection, it has over voltage, under voltage,lost phases protection function. The setting mainly used for hospital, shopping center, bank, and chemical industry, metallurgy, high building, military facilitiesetc I, II load important situation.