单项选择题
A.工频电压0.50m;操作过电压1.45m;雷电过电压1.90m B.工频电压0.55m;操作过电压1.45m;雷电过电压1.90m C.工频电压0.55m;操作过电压1. 50m;雷电过电压1.90m D.工频电压0.55m;操作过电压1. 55m;雷电过电压1.90m
A.最大设计风速 B.1/2最大设计风速 C.10m/s D.0m/s2
A.25片 B.30片 C.31片 D.32片