A 3 phase 4 pole synchronous motor, star connected 400 V 50 Hz serving a 72 hp load with a motor efficiency of 90%. The motor operates at a motor power factor of 0.8 lagging. If the synchronous reactance of the motor is 1 Ohm and the armature resistance is negligible determine: a. Anchor current

A 3 phase 4 pole synchronous motor, star connected 400 V 50 Hz serving a 72 hp load with a motor efficiency of 90%. The motor operates at a motor power factor of 0.8 lagging. If the synchronous reactance of the motor is 1 Ohm and the armature resistance is negligible determine: a. Anchor current

Electric Motor Control

10th Edition

ISBN:9781133702818

Author:Herman

Publisher:Herman

Chapter43: About Dc Motors

Section: Chapter Questions

Problem 1SQ

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Concept explainers

Synchronous Motor

The synchronous motor is an AC electric type motor where at a steady-state the shaft rotation is synchronized with the supply current variable-frequency. To an integral number of AC cycles, the rotation period is exactly equal. The stator of the motor in the synchronous motor contains multi-phase AC electromagnets due to which a magnetic field is created that rotates in time with the oscillation of the line current. The rotor contains a permanent magnet and the rotor rotates in synchronization with the stator field at the same rate and provides the second synchronized magnetic field which is rotating in nature as a result. When the synchronous motor is supplied with independently excited multi-phase AC electromagnets on both the rotor and the stator, it is termed as a doubly-fed machine. The most widely used AC-type motors are the synchronous AC motor and the induction AC motors.

Question

A 3 phase 4 pole synchronous motor, star connected 400 V 50 Hz serving a
72 hp load with a motor efficiency of 90%. The motor operates at a motor
power factor of 0.8 lagging. If the synchronous reactance of the motor is 1
Ohm and the armature resistance is negligible determine:
a. Anchor current

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