AC tachogenerator DC tachogenerator The AC tachogenerator is use to measure speed only in one direction only. The DC tachogenerator is. A.C. Tachogenerator • 2. D.C. Tachogenerator; 6. CONSTRUCTION • An Armature is rotating type & this magnet is fixed type. • Armature is. The DC tachometer works on the principle that when the closed conductor moves in the The drag cup Tachogenerator generates the ripple free output voltage.

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The machine whose speed is to be measured is coupled with the shaft of the DC tachometer generator. A generator specially designed and constructed for this use is called a tachometer or tachogenerator.

The mechanical tachometer measures the speed of shaft regarding revolution per minutes. The resistance is connected in series with the voltmeter for controlling the heavy current of the sc.

What is Electrical Tachometer? – DC & AC Tachometer Generator – Circuit Globe

Tachogenerayor on the natures of the induced voltage the electrical tachometer is categorized into two types. The DC tachometer works on the principle that when the closed conductor moves in the magnetic field, EMF induces in the conductor. Your email address will not be published. R L represents the electric load connected to the tachometer. Both of the latter two drawbacks are caused by the presence of the commutator in the d. C tachogenerator is shown in below figure.


The relative motion induces the EMF in the coil which is placed between the tachogeneratof magnetic field of the permanent magnet.

D.C Tachogenerators

In this post, i am interested in covering the details about how to measure flow using Orifice meter. The commutator collects current from armature conductors and converts internally induced a. The polarity of output voltage indicates the direction of rotation. You May Also Like: Now as the field of the permanent field is fixed, the e. Although a voltage divider could theoretically be used with a tachogenerator to extend the measurable speed range in the volt scale, it is not advisable to significantly overspeed a precision instrument like this, or its life will be shortened.

The equivalent circuit of a tachogenerator is also the dual of an electric motor and is shown in Figure Leave a Reply Cancel reply Your email address will not be published. Thus, either amplitude or frequency is used for measuring the angular velocity.

Basic Principle of Hot wire Anemometer When an electrically heated wire is placed in a flowing gas stream, heat is transferred from the w Its main drawbacks, on the other hand, are that it has an analogue output which requires AID tacjogenerator when interfaced to a computer ; the output can suffer from large fluctuations, and it has a shorter operational life.

Thus it is mostly used for measuring the rotational speed of the shaft. The below mention circuit is used for measuring the speed of the rotor by considering the amplitude of the induced voltage. The electrical tachometer has more advantages over the mechanical tachometer.


When not connected to a load resistance, generators will generate voltage roughly proportional to shaft speed. Vc armature of the DC generator revolves between the constant field of the permanent magnet. The rotation induces the emf in the coil. The rotor is made of the highly inductive material which has low inertia. The series resistance is used to limit the current under output short circuit condition.

This phenomena is therefore the same tachogeneraator gives rise to the back electromotive force b. The input is provided to the reference winding, and the output is obtained from the quadrature winding. By measuring the voltage produced by a tachogenerator, you can easily determine the rotational speed of whatever its mechanically attached to.

In the tachogenerator case the magnetic flux density B and the loop length l are constants, so the output voltage V o is proportional to the shaft angular velocity W, as tachogennerator and a shown previously in eqn 1. The moving coil voltmeter measures the induced emf.

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