单项选择题
A.measured B.recorded C.transferred D.controlled
When two different metals are joined to form a closed c...
单项选择题When two different metals are joined to form a closed circuit and exposed to different temperatures at their junctions （） which can be used to measure temperature.
A.a current will flow B.a power will develop C.a heat will flow D.a pressure will produce
（） is provided to alternators, in the event of prime mo...
单项选择题（） is provided to alternators, in the event of prime mover failure to ensure that the alternator does not act as a motor.
A.Reverse current protection B.Reverse power protection C.Synchronising device D.Frequency meter
To parallel an incoming machine to a running machine th...
单项选择题To parallel an incoming machine to a running machine therefore it is necessary to ensure firstly that （）.
A.two frequencies must be brought into phase B.the incoming machine accepts a small amount of load C.the running machine must be unload D.both voltages are equal
