
Concept explainers
What is the purpose of phase failure relays?

State the purpose of phase failure relays.
Answer to Problem 1SQ
The purpose of phase failure relay is to disconnect the loads on the event of phase failure.
Explanation of Solution
Phase failure relay:
Phase failure relay are the type of protective relays. When the three-phase motor is running, if a fuse blows or the wire connected to motor breaks, the motor will operate in single-phase but the serious over-heating might occur. To prevent the motor from these situations, phase failure relay is utilized.
The main purpose of phase failure relays is to disconnect loads, like motors, from the power supply in the event they fail.
Conclusion:
Thus, the purpose of phase failure relay is to disconnect the loads on the event of phase failure.
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Chapter 14 Solutions
Electric Motor Control
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