Which statement is true regarding the functionality of a tachometer in troubleshooting?

The tachometer is a device specifically designed to measure the rotational speed of an object, typically in revolutions per minute (RPM). In the context of troubleshooting machinery, knowing the speed at which components are operating is crucial. A tachometer provides real-time feedback on how fast motors and other rotating equipment are functioning, allowing a millwright to identify issues such as underperformance, overloading, or other mechanical failures that may be related to speed variations.

The ability to indicate speed is essential in diagnosing problems that could arise from incorrect operational speeds, which could affect the overall efficiency and functionality of machinery. By monitoring the RPM, technicians can ensure that components are running within their designed specifications, thus aiding in effective troubleshooting.

Other options, such as measuring flow, pressure, or temperature, pertain to different types of sensors and devices used in mechanical systems, but they are not the function of a tachometer. The primary role of the tachometer remains centered around speed measurement, which is vital in many troubleshooting scenarios.