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單項選擇題

Equal power factors on paralleled AC generators are maintained by an automatic （）.

A.voltage regulator
B.reverse power relay
C.reverse current relay
D.governor control switch

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單項選擇題

To equalize the power factor of two alternators operating in parallel, the （）

A.field excitation of both units is adjusted
B.governors of both units are adjusted
C.phase sequence is altered
D.kilowatt load is evenly divided

單項選擇題

An advantage of DC motors over AC motors is that they （）

A.are less expensive
B.require less maintenance
C.can be started across the line
D.offer a more effective means of controlling speed

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