Understanding Motor Controls
3rd Edition
ISBN: 9781305498129
Author: Stephen L. Herman
Publisher: Cengage Learning
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Chapter 25, Problem 1RQ
To determine
Identify why it is desirable to disconnect the autotransformer from the circuit hen the motor reaches the run stage.
Expert Solution & Answer
Explanation of Solution
The autotransformer is used to reduce the amount of inrush current by reducing the voltage applied to the motor at the time of starting. When the motor reaches 75% of the normal speed it is said to have reached run state.
After reaching the run state, full voltage can be supplied to the motor. The use of autotransformer to provide full voltage to the motor is a waste of energy as the same can be applied directly.
Hence, it is desirable to disconnect the autotransformer after the motor reached the run state to save energy and extend the life if the autotransformer.
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Chapter 25 Solutions
Understanding Motor Controls
Ch. 25 - Prob. 1RQCh. 25 - Explain the differences between open and closed...Ch. 25 - Prob. 3RQCh. 25 - Refer to the circuit shown in Figure 252. Assume...Ch. 25 - Prob. 5RQCh. 25 - Prob. 6RQCh. 25 - Prob. 7RQCh. 25 - Refer to the circuit shown in Figure 255. Explain...Ch. 25 - Prob. 9RQCh. 25 - Refer to the circuit shown in Figure 25–5. Assume...
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