单项选择题
A.draw a one line diagram of the circuitry B.test all fuses and measure the line voltage C.take megger readings D.insulate the apparatus from ground
A circuit breaker differs from a fuse in that a circuit...
单项选择题A circuit breaker differs from a fuse in that a circuit breaker （）.
A.melts and must be replaced B.is enclosed in a tube of insulating material with metal ferrules at each end C.gives no visual indication of having opened the circuit D.trips to break the circuit and may be reset
Voltage generated by most AC generators is fed from the...
单项选择题Voltage generated by most AC generators is fed from the machine to the bus by means of（）.
A.brushes on a commutator B.brushes on slip rings C.slip rings on a commutator D.direct connections from the stator
Electrical leads and insulation on a motor should be pa...
单项选择题Electrical leads and insulation on a motor should be painted with（）.
A.heat-resisting acrylic B.heat-resisting aluminum C.insulating varnish D.insulating white lead
