单项选择题
A.ampere B.volt C.watt D.ohm
Some large A-Cmotors are equipped with heatersThese cou...
Some large A-Cmotors are equipped with heatersThese could be （） (1)resistance heaters bolted directly to the frame (2)low voltage windings embedded in the motor windings
A.(1) only B.(2) only C.either (1) or (2) D.neither (1) or (2)
In order to change the direction of rotation of a D-Cmo...
In order to change the direction of rotation of a D-Cmotor （） (1) the field leads must be changed (2) the input leads must be changed
A.（1）only B.（2）only C.either（1）or（2） D.neither（1）or（2）
If a small electric motor is immersed in salt water it ...
If a small electric motor is immersed in salt water it should be （） (1) washed in fresh water (2) dried in an oven
A.(1) only B.(2) only C.both (1) and (2) D.neither (1) or (2)
