单项选择题
A.90~0 kw B.127~27 kw C.155~70 kw D.194~85 kw
Sparking at the brushes of a running motor could be an ...
单项选择题Sparking at the brushes of a running motor could be an indication of （）.
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
