To meet the need of accurately measuring the speed of rotating equipment, a large variety of sensors, indicators and controls have been created: each combination providing the best, or least expensive( or both), solution for a specific application.

To that end, Industrial quality tachometers are either hand-held or continuous operation, and either mechanical or electrical/electronic. Direct coupled mechanical tachometers for continuous RPM measurement are becoming extremely rare, as the electrical/electronic types are comparatively inexpensive and much more versatile. However, some mechanicals are still available.

Hand Tachometer

Contact

Contact types are available with analogue dials or, as is more common, with LCD or LED displays. The LCD type of display is preferred due to battery life; the LED version is best for poorly lit operations. Extreme care must be taken when making measurements with contact tachometers; the rotating device should be stopped, the contact tachometer placed, and the rotations slowly brought up to speed.

The above are available with a Cone as well as measuring wheels.

Non-Contact

The most popular non-contact type of hand tachometer is the phototach. The instrument operates by directing a collimated light beam onto a reflective marker attached to the rotating object and the reflections received back by the instrument are compared to an internal crystal time base for extremely accurate measurements.