单项选择题
As a general rule, the first troubleshooting action to be taken in checking faulty electric control devices is to （）.
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
单项选择题 A circuit breaker differs from a fuse in that a circuit breaker （）.
单项选择题 Voltage generated by most AC generators is fed from the machine to the bus by means of（）.
单项选择题 Electrical leads and insulation on a motor should be painted with（）.
