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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Mechanical and electrical are the two types of the tachometer. The commutator collects current from armature conductors and converts internally induced a. Tachogenerators are frequently used to measure the speeds of electric motors, engines, and the equipment they power: When not connected to a load resistance, generators will generate voltage roughly proportional to shaft speed. tacuogenerator

A very basic transducer which is always useful in the field of instrumentation, I 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 rotor is made of the highly inductive material which has low inertia. The amplitude and frequency of the induced emf are equivalent to the speed of the shaft.

The electrical tachometer converts the angular velocity into an electrical voltage. The AC tachometer generator designs for reducing the problems.

Difference between AC tachogenerator and DC tachogenerator – Polytechnic Hub

In measurement and control systems where directional indication is needed, tachogenerators provide an easy way to determine tachoggenerator.

Quote of the day. By measuring the voltage produced by a tachogenerator, you can easily determine the rotational speed of whatever its mechanically attached to. The machine whose speed is to be measured is coupled with the shaft of the DC tachometer generator.

C tachogenerator is shown in below figure. The rotation of rotor between the magnetic field induces the voltage in the sensing winding. Figure 2 Tachogenerator equivalent circuit. The resistance is connected in series with the voltmeter for controlling the heavy current of the armature.


C Tachogenerator is kept in tachogenerxtor permanent magnetic field. The rotation induces the emf in the coil. The magnitude of the induces emf depends on the flux link with the conductor and the speed of the shaft.

Published under the terms and conditions of the Design Science License. The equivalent circuit of a tachogenerator is also the dual of an electric motor and is shown in Figure Now as the field of the permanent field is fixed, the e.


The DC tachometer works on the principle that when the closed conductor moves in the magnetic field, EMF induces in the conductor. In this post, i am interested in covering the details about how to measure flow using Orifice meter.

Tachogenerators Chapter 9 – Electrical Instrumentation Signals. When the shaft of the machine revolves, the armature of the tachogenerator revolves in the magnetic field producing e. R L represents the electric load connected to the tachometer.

The DC tachometer generator uses the commutator and brushes which have many disadvantages. I have prepared a list of instrumentation and control engineering gheory companies in India, which you should must know. An electromechanical generator is a device capable of producing electrical power from mechanical energy, usually the turning of a shaft. It works on the principle of relative motion between the magnetic field and shaft of the coupled device. A generator specially designed and constructed for this use is called a tachometer or tachogenerator.

Permanent magnet, armature, commutator, brushes, variable resistor, and the moving coil voltmeter are the main parts of the DC tachometer generator. The commutator converts the alternating current of the armature coil to the direct current with the help of the brushes.

The constant of proportionality K t is generally linear within a large dynamic range but does vary in relation to: Its main drawbacks, on the other hand, are that it has an analogue output which requires AID conversion when interfaced to a computer ; the output can suffer from large fluctuations, and it has a shorter operational life.


The tacjogenerator voltage is proportional to the speed of the rotation. With precise construction and design, generators can be built to produce very precise voltages for certain ranges of shaft speeds, thus making them well-suited as measurement devices for shaft speed in mechanical equipment.

The output voltage V o can be in direct current form in the case of the dynamo a d.

Basic Principle of Hot wire Anemometer When an electrically heated wire is placed in a flowing gas stream, heat is transferred from the w Follow Us likes followers subscribers. The rotor of the tachometer is made with thin aluminium cup, and it is placed between the field structure.

Thus, either amplitude or frequency is used for measuring the angular velocity. The AC tachometer has stationary armature and rotating magnetic field.

The mechanical tachometer measures the speed of shaft regarding revolution per minutes. Leave a Reply Cancel reply Your email address will not be published.

D.C Tachogenerators

The develops EMF is directly proportional to the speed of the shaft. Depends on the natures of the induced voltage the electrical tachometer is categorized into two types. The induces voltages are rectified and then passes to the capacitor filter for smoothening the ripples of rectified voltages.

The relative motion induces the EMF in the coil which is placed between the constant magnetic field of the permanent magnet. The polarity of the induces voltage determines the direction of motion of the shaft. This phenomena is therefore the same which gives rise to the back electromotive force b. One of the more common voltage signal ranges used with tachogenedator is 0 to 10 volts.

Both of the latter two drawbacks are caused by the presence of the commutator in the d.