Electric Motor Control
Electric Motor Control
10th Edition
ISBN: 9781133702818
Author: Herman
Publisher: CENGAGE L
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Chapter 25, Problem 1SQ
To determine

What are the five commonly used starting methods for the motors.

Expert Solution & Answer
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Explanation of Solution

Generally, the polyphase induction motor is a self-starting motor. The commonly used starting methods for a polyphase squirrel cage induction motor are as follows:

  1. 1. Full-voltage starting:

    An automatic starting or hand-operated switch is connected to the motor directly across the line.

  2. 2. Primary-resistance starting:

    A resistance unit is connected in series with a stator to reduce the starting current.

  3. 3. Autotransformer or compensator starting:

    Low voltage starting is applied by performing an automatic or manual switching between the taps of an autotransformer.

  4. 4. Impedance starting:

    A reactor is connected in series with a motor to reduce the starting voltage.

  5. 5. Star-delta starting:

    To get the reduced starting voltage, a stator is connected in star connection for starting and delta connection for running condition.

Conclusion:

Thus, the commonly used starting methods for a polyphase squirrel cage induction motor are listed.

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