Which of the following speed control devices is used strictly as a safety device to prevent prime mover damage and acts by shutting down the prime mover?

Correct Answer: Option A — Over speed trip

An overspeed trip is a dedicated safety device designed to protect prime movers from catastrophic mechanical failure. Unlike a governor, which modulates speed during normal operation, the overspeed trip acts independently to immediately shut down the fuel or steam supply if the machine exceeds its safe operating rotational speed.