What is the role of a governor in generator operation?

• A. To control prime mover speed and maintain system frequency under changing load.
• B. To regulate coolant flow.
• C. To adjust generator voltage.
• D. To monitor bearing wear.

Answer: (A)

The governor’s job is to keep the generator’s speed, and therefore the system frequency, constant as load changes. It does this by sensing the actual speed of the prime mover and comparing it to a reference speed. When electrical load increases and speed tends to drop, the governor opens the fuel supply to the prime mover to speed things up. When load decreases and speed tends to rise, it reduces fuel to bring speed back down. This automatic speed control is what keeps the grid frequency stable during shifting demand.

The other functions belong to different parts of the system: coolant flow is controlled by the cooling system, not the governor; generator voltage is regulated by the automatic voltage regulator; bearing wear is monitored as part of maintenance and condition monitoring.