Steam turbine governors primarily

• A. Prevent the turbine from over speeding
• B. Regulate the speed of the turbine automatically
• C. Should be checked annually by the boiler inspector
• D. Are not required on reaction turbines

Answer: (B)

Governors are used to automatically regulate turbine speed. They continuously monitor the turbine’s rotational speed and adjust the inlet steam to keep the speed near the desired set point as load changes. When load increases, speed would tend to drop, so the governor opens the steam valve to raise speed; when speed rises too much, the governor closes the valve to bring it back down. This automatic control is central to how a steam turbine operates in a power plant.

That’s why regulating the speed automatically is the best description of a governor’s primary role. Overspeed protection is a safety function that may be part of the system, but the main purpose is automatic speed regulation. Annual checks by a boiler inspector aren’t the defining function of the governor, and reaction turbines do use governors, so the statement that they aren’t required on reaction turbines isn’t correct.