单项选择题
A.without switches on it B.with insulated switches and no exposed terminals C.without circuit breakers D.without safety hand nails nor rubber mats
A.larger than the greatest branch resistance B.smaller than the lowest branch resistance C.equal to the sum of the individual branch resistances D.one-half the sum of the individual branch resistances
A.result in decreased acceleration time only B.lower the starting current and increase accelerating time C.cause a greater starting torque D.increase the starting current and pump capacity