Chapter 24, Problem 1SQ

In the event of line voltage fluctuations or failure, how is the starter maintained in a closed position?

To determine

Explain how the starter is maintained in a closed position during the event of line voltage fluctuations or failure.

Explanation of Solution

If the time is delayed, low-voltage release relay device is used with the magnetic starter and a momentary contact push button station; the motor can automatically reconnect with the power lines after a voltage failure or voltage fluctuations of short duration.

Refer to Figure 24-2 in the textbook, the electrolytic capacitor represented as C1 is charged through the rectifier. If the line voltage fluctuates or fails completely, the electrolytic capacitor can discharge through the control relay to maintain the coil as energized through which the starter can be maintained in a closed position. The discharging time required by the capacitor is a function of resistance in the circuit and capacitance of the device.

Conclusion:

Thus, the process of a starter maintained in a closed position during the event of line voltage fluctuations or failure is explained.