Which device is used to measure the speed of a turbine?

The device that measures the speed of a turbine is a tachometer. A tachometer specifically measures the rotational speed of an object, such as a turbine, in revolutions per minute (RPM). This is crucial for monitoring performance and ensuring that a turbine operates within its designed speed range, thereby assisting in diagnostics and operational efficiency.

In the context of monitoring turbines, knowing the exact speed is essential, as it affects the overall performance, efficiency, and safety of the system. For instance, operating a turbine at too high a speed can lead to mechanical failure, while too low a speed may indicate that the turbine is not performing effectively.

Other devices listed, such as pressure gauges, flow meters, and thermometers, serve different purposes. A pressure gauge measures the pressure of gases or liquids, a flow meter measures the flow rate of a liquid or gas, and a thermometer measures temperature. While these instruments are all important in their respective domains, they do not measure rotational speed, which is specifically the function of a tachometer.