A 480-V, 60 Hz, 400-hp 0.8-PF-leading eight-pole A-connected synchronous motor has a synchronous reactance of 0.6 2 and negligible armature resistance. Ignore its friction, windage, and core losses for the purposes of this problem. Assume that EA is directly proportional to the field current IF, and that |EA|= 480 V when IF = 4 A. a) What is the speed of this motor? b) If this motor is initially supplying 400 hp at 0.8 PF lagging, what are the values of IA and EA? c) How much torque is this motor producing? What is the torque angle 8? How near is this value to the maximum possible induced torque of the motor for this field current setting? d) If E is increased by 30 percent, what is the new magnitude of the armature current? What is the motor's new power factor? e) Plot the motor's V-curve for this load condition.

A 480-V, 60 Hz, 400-hp 0.8-PF-leading eight-pole A-connected synchronous motor has a synchronous reactance of 0.6 2 and negligible armature resistance. Ignore its friction, windage, and core losses for the purposes of this problem. Assume that EA is directly proportional to the field current IF, and that |EA|= 480 V when IF = 4 A. a) What is the speed of this motor? b) If this motor is initially supplying 400 hp at 0.8 PF lagging, what are the values of IA and EA? c) How much torque is this motor producing? What is the torque angle 8? How near is this value to the maximum possible induced torque of the motor for this field current setting? d) If E is increased by 30 percent, what is the new magnitude of the armature current? What is the motor's new power factor? e) Plot the motor's V-curve for this load condition.

Introductory Circuit Analysis (13th Edition)

13th Edition

ISBN:9780133923605

Author:Robert L. Boylestad

Publisher:Robert L. Boylestad

Chapter1: Introduction

Section: Chapter Questions

Problem 1P: Visit your local library (at school or home) and describe the extent to which it provides literature...

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