A.三相四线制50Hz,400V交流电源 B.三相四线制50Hz,110V交流电源 C.三相四线制100Hz,400V交流电源 D.三相四线制100Hz,110V交流电源
A.1550V B.1650V C.1750V D.1850V
A.V1 B.V2 C.V3 D.V4