Voltage undervoltage protection

Undervoltage Protection. Undervoltage relays and three-wire control are employed to initiate the opening of a motor circuit and maintain it open on a reduction or failure of voltage. Undervoltage protection generally is applied where uncontrolled motor starting could result in potential hazards. 

Thus, the protection will not prevent the closing of the contactor or the breaker when the supply voltage is 85% or more, nor will it trip the motor until the voltage falls to a low of 65% of the rated voltage. In both cases, therefore, separate undervoltage protection will be essential. This problem, however, is a theoretical one, as an industrial power system would seldom fluetuate so widely. 

Protection Overcurrent, overvoltage, short circuil, overtemperature, and undervoltage. No damage caused by output short circuit. The inverter must shut down if the input voltage dips below the minimum input of 42 V. Inverter should not self-reset after a load-side fault... 

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