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單項選擇題

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)

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單項選擇題

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）

單項選擇題

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)