Concept explainers
What are the five commonly used starting methods for the motors.
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. Full-voltage starting:
An automatic starting or hand-operated switch is connected to the motor directly across the line.
- 2. Primary-resistance starting:
A resistance unit is connected in series with a stator to reduce the starting current.
- 3. Autotransformer or compensator starting:
Low voltage starting is applied by performing an automatic or manual switching between the taps of an autotransformer.
- 4. Impedance starting:
A reactor is connected in series with a motor to reduce the starting voltage.
- 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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