Engineering · Electrical — Generators
Before paralleling two AC generators, they must be matched for:
- AVoltage and oil pressure only
- BVoltage, frequency, phase sequence, and phase angle✓ Correct
- CFrequency only
- DLoad and temperature
Explanation
To parallel AC generators safely the incoming machine must match the bus in voltage, frequency, phase rotation/sequence, and be in phase at the moment the breaker closes (synchroscope at slow approach to 12 o'clock).
Authority: Marine Electrical (USCG engineering topic)
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