The primary function of steam turbine governors is to

• A. Prevent over speeding
• B. Regulate speed automatically
• C. Adjust steam pressure for maximum energy
• D. Ensure zero maintenance

Answer: (B)

The key idea is automatic speed control. The governor keeps the turbine running at a chosen speed by automatically adjusting how much steam enters the turbine as load changes. It senses the actual speed, compares it to a setpoint, and opens or closes the steam valve to speed up or slow down the turbine accordingly. If the load tends to push the speed up, the governor reduces steam flow to bring it back down; if the load drops, it increases steam flow to maintain the target speed. Overspeed protection is a safety outcome of this control, but the primary function is regulating speed automatically.