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

The tachometer is the device designed specifically for measuring the speed of rotating machinery, including turbines. It provides a direct measurement of the rotational speed, often expressed in revolutions per minute (RPM). This parameter is crucial in various applications, particularly in power generation and other industrial settings where turbine efficiency and performance need to be monitored.

The other devices serve different purposes: pressure gauges monitor the pressure of gases or liquids, flow meters measure the volume or mass of fluid flow, and thermometers gauge temperature. While these instruments provide valuable information in their respective areas, they do not measure the rotational speed of turbines. Thus, the tachometer is the appropriate instrument for this specific function.