A three-phase alternator operates at 450 volts with a power factor of 0~8.If the ammeter indicates 250 amperes, what should be the KW meter reading （）.

A.normal operation
B.a dirty commutator
C.increased brush capacity
D.water vapor absorption

A.high mica condition
B.low ambient temperature
C.clogged ventilation ducts
D.an open in the shunt field

A.ampere
B.volt
C.watt
D.ohm