Dictionary of Electrical Engineering

Commonly used terms in the Electrical industry.

digital tachometer
a device with a sensor that senses pulses from a rotating axis and converts them to digital output calibrated in rotations per minute (rpm).
a instrument used to measure the speed of a rotating device. Several types of tachometers are available. Friction devices are placed against the shaft of the device being measured. Others used magnetic variation or reflected light pulses to determine the speed. Tachometer generators are mounted on the shaft of the device being measured and provide a voltage proportional to the speed. Tach generators are often used in servo systems.
a small generator that is connected to the shaft of a rotating machine and produces an output voltage directly proportional to the rpm of the machine. Typically used for closed-loop speed control.