Under voltage protection provided for A.C generators

• An Under-voltage release is fitted to trip main circuit breaker of the alternator.
• It trips the alternator breaker when a severe voltage dip occurs.
• If the circuit breaker of a dead generator is closed in parallel with another running generator, it will be equivalent to a short circuit fault on the alternator.
• This can damage the alternator and also result in a complete blackout of the electrical system.
• The Undervoltage release of a generator breaker also prevents such closing during synchronization, if the AC generator output voltage is low or zero.