A threes-phase synchronous motor connected to ac mains is running at full load and unity power factor. If its shaft load is reduced by half, with field current held constant, its new power factor will be
A. unity.
B. leading.
C. lagging.
D. dependent on machine parameters. [GATE E E. 2007]
Answer:B
A threes-phase synchronous motor connected to ac mains is running at full load and unity power factor. If its shaft load is reduced by half, with field current held constant, its new power factor will be
A. unity. B. leading. C. lagging. D. dependent on machine parameters. [GATE E E. 2007]