A 30 hp, three-phase, wye connected, 60 Hz, 360 VLL, synchronous motor is operating at 50% full load, rated voltage and 0.8 pf leading (over-excited). The motor has negligible armature resistance and a synchronous reactance of 2.5 2/phase. Stator core loss is 1kW and friction and windage loss is 1.5 kW. a. Draw a phasor diagram to illustrate the leading power factor operating condition. Show symbols only b. Calculate the motor line-to-neutral excitation voltage and load angle when it is operating at 50% full load, rated voltage and 0.8 pf leading (over-excited). C. Draw a phasor diagram to illustrate the lagging power factor operating condition. Show symbols only

A 30 hp, three-phase, wye connected, 60 Hz, 360 VLL, synchronous motor is operating at 50% full load, rated voltage and 0.8 pf leading (over-excited). The motor has negligible armature resistance and a synchronous reactance of 2.5 2/phase. Stator core loss is 1kW and friction and windage loss is 1.5 kW. a. Draw a phasor diagram to illustrate the leading power factor operating condition. Show symbols only b. Calculate the motor line-to-neutral excitation voltage and load angle when it is operating at 50% full load, rated voltage and 0.8 pf leading (over-excited). C. Draw a phasor diagram to illustrate the lagging power factor operating condition. Show symbols only

Electricity for Refrigeration, Heating, and Air Conditioning (MindTap Course List)

10th Edition

ISBN:9781337399128

Author:Russell E. Smith

Publisher:Russell E. Smith

Chapter8: Basic Electric Motors

Section: Chapter Questions

Problem 46RQ: Explain the operation of the direct current motor used in mini-split units.

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