A.C. POTENTIOMETER. Its principle is same as a But in an a.c. potentiometer, not only the magnitudes but phases as well DRYSDALE POLAR TYPE AC. Posts about polar type ac potentiometer written by Pragnarongali. The working principle of the AC potentiometer is same as that of the DC potentiometer, i.e., the unknown voltage is determined by Polar Type Potentiometer.

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This working current through the slide wire may be varied by changing the rheostat setting. But there is one major difference between their measurements, DC potentiometer only measures the magnitude of the unknown voltage. The slide a.c.potenriometer type of potentiometer is not a practical form of drysdsle.

The reading of a sensitive dynamometer type ammeter in the main circuit is noted. Between the stators, there is laminated rotor having slots and winding which supplies voltage to the slide-wire circuit of the Potentiometer. In order to operate the galvanometer at its maximum sensitivity, provision is made to short the protective resistance when near the balance conditions.

There q.c.potentiometer two step-down transformers T 1 and T 2 which isolate potentiometer from the line and give an earthed screens protection between the winding.

Thus, the drtsdale and current may vary at different power factor. The coordinate type potentiometer has two scales to read the inphase V 1 component, and the quadrature component V 2 of the unknown voltage V.

What is AC Potentiometer? Definition, Types & Applications – Circuit Globe

If the dial settings are exactly the same as in the original calibration procedure, a valid measurement has been made. Coordinate type Potentiometer In coordinate AC potentiometertwo separate potentiometers are caged in one circuit as shown in the figure. When current start flowing from stators, the rotating field is developed around the rotor and due to it e. Drysdale’s Alternating and Continuous Current Potentiometer.


It gives the accurate results in magnetic testing and precise testing of instrument transformers.

AC Potentiometer

The potentiometer, which is the universal instrument by which currents are determined in terms of a difference of potential between the end of a known resistance, has been developed by C.

There are two types of AC potentiometers: For higher frequencies a telephone may be used. Measurements of Self Reactant of a Coil — The standard reactance is placed in series with the coil whose reactance is to be measured.

Applications of AC Potentiometer Measurement of self-inductance. The “balance” is obtained by successive approximation of the usual adjustment of the potentiometer contacts dial and slide wire reading and of the phase-shifting transformer until the indicator shows no deflection.

Polar type Potentiometer In such type of instruments, two separate scales are used to measure magnitude and phase angle on some reference of the unknown e.

By doing some adjustments in sliding contacts and rheostat, the whole circuit gets balanced and galvanometer reads zero at the balanced condition. The known voltage may be supplied by a standard cell or any other known voltage-reference source. Click on the Images For Detail.

AC Potentiometers

It also supplies 6 volts to potentiometers. C potentiometer is an accurate and versatile instrument and thus it is obvious that the potentiometer principle can be applied to measurement of alternating currents and voltages.

This is accomplished by supplying it through a phase-shifting transformer which consists of a stator wound with a circuit, which produces a rotating field in a closely-fitting rotor. The method of measuring unknown voltage E depends on finding a position for the sliding contact such that the galvanometer a.c.potentiomefer zero deflection when galvanometer key K is closed. These are adjusted until the A. The function of the series components is to maintain constant AC supply in the potentiometer by doing small adjustments in it.


Please be assured that any amount you feel able to donate will make an immediate and significant impact. Thus, the resultant voltage of the coordinate A.c.potentiometr potentiometer is And the phase angle is given by. The protective resistance is left in the circuit to avoid damage to the galvanometer during the initial stages oplar adjustment.

This is done by switching it over on to a continuous current circuit, which is adjusted until a balance is obtained at the proper setting, when a Weston cell is connected up in the usual manner. S 1 and S 2 are signs changing switches which are used to change the polarity of the test voltage if it is required for balancing the Potentiometer.

Drysdale ac polar potentiometer

The slide wire is carefully manufactured and has uniform resistance along its entire length. It is an instrument designed to measure an unknown voltage by comparing it with a known voltage.

Drysdale’s Alternating and Continuous Current Potentiometer The instrument comprises the standard Tinsley DC potentiometer of the time, with a phase shifter, Weston dynamometer voltmeter, selection and change-over switches and terminal panels for connection of galvanometers, DC and AC measuring and supply voltages. Ammeter Calibration — The measurement of the alternating current may be measured by the use of non-inductive standard resistor with the potentiometer.

The known source may be DC or A.c.optentiometer. Precision laboratory potentiometers usually have three voltage ranges a high range 1.