Tachometer

Tachometer of a motorcycle

Tachometer of a diesel locomotive

Tachometer in a light aircraft

Shaft of a tachometer on a motorcycle

A tachometer , also called a tour counter , is a measuring device that measures and displays the speed of a shaft .

Tachometers are available in a wide variety of designs, e.g. B. mechanically or electrically, as a built-in or handheld device. Gyrometers were used in the past . The various measuring principles are explained under speed measurement .

use

In machine and vehicle construction, tachometers are used to monitor the running or the speed of machines and motors and to keep them in a damage-free, economically optimal or a specially required operating range. To this end, they are often provided with markings that indicate the area in which operation can be harmless or potentially damaging.

Executions

In four-stroke engines , it used to be common for the rev counter to be driven by the camshaft , which runs at half the speed of the crankshaft. Early electronic tachometers, which were also suitable for retrofitting, determined the speed from the frequency on the feed line of the breaker contact with a frequency-voltage converter ( monoflop and voltage measuring device ).

With the replacement of interrupter contacts and purely mechanical engine controls by transistor ignitions and electronic control units, the electronic detection of the engine speed was implemented without contact as the basis of engine function using Hall sensors , and also made available for tachometers.

Components with a tachometer function are often used on vehicles, which indirectly enable speed display and monitoring, for example by measuring the wheel speed and an adapted scale .