单项选择题
A.normal operation B.a dirty commutator C.increased brush capacity D.water vapor absorption
If a DC motor runs hot, the cause may be （）A.high mica ...
单项选择题If a DC motor runs hot, the cause may be （）
A.high mica condition B.low ambient temperature C.clogged ventilation ducts D.an open in the shunt field
The unit of electrical resistance is the （）A.ampereB.vo...
单项选择题The unit of electrical resistance is the （）
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)
