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 DC tachometer works on the principle that when the closed conductor moves in the magnetic field, EMF induces in the conductor. The magnitude of the induces emf depends on the flux tachogeneratkr with the conductor and the speed of the shaft. Although a voltage divider could theoretically be used with a tachogenerator to extend the measurable speed range in the volt scale, it is not tachogenerqtor to significantly overspeed a precision instrument like this, or its life will be shortened.

The commutator collects current from armature conductors and converts internally induced a.

D.C Tachogenerators

C Tachogenerator is kept in the permanent magnetic field. The induces voltages are rectified and then passes to the capacitor filter for smoothening the ripples of rectified voltages.

A very basic transducer which is always useful in the field of instrumentation, I Your email address thwory not be published. The tachogenerator is a direct-type velocity transducer. Permanent magnet, armature, commutator, brushes, variable resistor, and the moving coil voltmeter are the main parts of the DC tachometer generator. Figure 1 Typical transfer characteristic of tachogenerator. Follow Us likes followers subscribers. This phenomena is therefore the same which gives rise to the back electromotive force b.


R L represents the electric load connected to the tachometer. Thus it is mostly used for measuring the rotational speed xc the shaft. An electromechanical generator is a device capable of producing electrical power from mechanical energy, usually the turning of a shaft. The polarity of output voltage indicates the direction of rotation.

Tachogenerators can also indicate the direction of rotation by the polarity of the output voltage. The rotor is made of the highly inductive material which has low inertia.

Now as the field of the permanent field tachotenerator fixed, the e. The rotation induces the emf in the coil. By measuring the voltage produced by a tachogenerator, you can easily determine the rotational speed of whatever its mechanically attached to.

Difference between AC tachogenerator and DC tachogenerator – Polytechnic Hub

These variations are usually amply documented in the manufacturer data sheets and do not present a problem. The below mention circuit is used for measuring the speed of the rotor by considering the amplitude of the induced voltage.

The series resistance is used to limit the current under output short circuit condition. The polarity of the induces voltage determines the direction of motion of the shaft. The amplitude and frequency of the induced emf are equivalent to the speed of the shaft. And i am starting it from the scratch.


D.C Tachogenerators – Instrumentation and Control Engineering

The nonlinear relationship obtains between the output voltage and input speed when the rotor rotates at high speed. Thus, the commutator and brushes are absent in AC tachometer generator. The stator of the generator consists two windings, i.

The electrical theort has more advantages over the mechanical tachometer. Tachogenerators are frequently used to measure the speeds of electric motors, engines, and the equipment they power: C tachogenerator is shown in below figure. The input is provided to the reference winding, and the output is obtained from the quadrature winding. The DC tachometer generator uses the commutator and brushes which have many disadvantages.

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The develops EMF is directly proportional to the speed of the shaft. The resistance is connected in series with the voltmeter for controlling the heavy current of the tacohgenerator.

Mechanical and electrical are the two types of the tachometer.