7/23/2019 Tachometer Generator

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Tachometer Generator

(or electric-generator tachometer), a microelectric machine that is used to

convert the instantaneous values of the shaft or rotor speed of a machine or

mechanism into an electrical signal. The operation of the tachometer generator

is based on the fact that the angular rotational velocity of the generator rotor isproportional to the generated electromotive force if the excitation ux is

constant.

A distinction is made beteen A! tachometer generators, hich may be

synchronous or asynchronous, and "! generators. "! tachometer generators are

small commutator machines in hich the excitation ux comes from a

permanent magnet or a separate inding. #ynchronous tachometer generators

are small synchronous machines in hich the rotor is a permanent magnet.

The most common type is the asynchronous generator, hich is similar in design

to an asynchronous electric motor ith a hollo short-circuited rotor. $n this

design, to indings are located on the stator at an angle of %&'. ne is the

excitation inding, hich is fed by alternating current of constant freuency and

voltage* the other is the output inding, to hich can be connected a measuring

instrument, such as a voltmeter calibrated in revolutions per minute.

Tachometer generators are used as sensors of speed of rotation in various

automatic devices and in electromechanical computer apparatus.