单项选择题
A.used to do mechanical work B.used to establish the magnetic field of the motor C.lost as heat generated by the windings D.lost in doing work to turn the motor itself
A diesel driven emergency generator is prevented from b...
单项选择题A diesel driven emergency generator is prevented from being paralleled with the ships service generators by （）
A.an electrical interlock system B.an automatic paralleling trip switch C.the synchronizing oscilloscope D.the reverse current relay
A motor enclosure which protects against falling liquid...
单项选择题A motor enclosure which protects against falling liquids is classified as （）
A.waterproof B.drip proof C.spray tight D.spray proof
Universal motors will operate on AC or DC current, and ...
单项选择题Universal motors will operate on AC or DC current, and are generally found in （）
A.portable tools B.large pump motors C.turbo electric main motors D.forced draft fans
