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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The operation of the AC potentiometer is quite complicated as compared to the DC potentiometer. These instruments are provide with two scales to read respectively the inphase component V1 and the quadrature component V2 of the unknown voltage V. The pokar of measuring unknown voltage E depends on finding a position for the sliding contact such that the galvanometer shows zero deflection when a.c.potrntiometer key K is closed.
The rotor has a winding on it which supplies the potentiometer current. In this potentiometer, the magnitude of the unknown voltage is measured from one scale, and its phase angle is directly on the second scale. In order to obtain a balance, as indicated by the deysdale instrument, it must be possible to give to the potentiometer current any phase displacement relative to that of the potential supplying it.
The instrument is balanced by the main dial and the slide wire, leaving the protective resistance again in the circuit. The working principle of the AC potentiometer is same as that of the DC potentiometer, i.
Where as, AC potentiometer measures both the magnitude and phase of unknown voltage by comparing it with known reference. Since the resistance of the slide wire is known accurately, the voltage drop along the entire slide wire or along any position of it, can be controlled by adjusting the working current.
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. Drrysdale doing some adjustments in sliding contacts and rheostat, the whole circuit gets balanced and galvanometer reads zero at the balanced condition.
If the reading does not agree, a second measurement must be made, again returning to a calibration check after completion. After the standardization has been completed the switch is thrown to the operate position, thus connecting the unknown e. Drysvale Design by Pure Energy.
The main circuit of the potentiometer must be supplied with alternating current of exactly the same frequency as that in the circuit to be measured, which means in practice that they must be supplied from the same source. The whole arrangement of the winding is done in such a way that the magnitude of the induced emf in the rotor may change but it does not affect the phase angle and it can be read on the scale fixed on the a.c.potehtiometer of the instrument. Leave a Reply Cancel reply Your email address will not be published.
The function of the series components is to maintain constant AC supply in the potentiometer a.c.potentiomter doing small adjustments in it. As balance is approached, the protective resistance is shorted and final adjustments are made drysdake obtain a true balance condition.
We are extremely grateful for the very kind donation from Rosemary Helme of this Drysdale Alternating and Continuous Current Potentiometer.
Further, the phase relation between the circuit to be measured and that supplying the potentiometer may have any value from to By continuing to use this website, you agree to their use. The known source may be DC or AC.
These are adjusted until the A. The most important difference between a d.
As it is necessary to have the splitphase circuit somewhere near the resonating point, it must be adjusted for changes of frequency.
Since dryysdale potentiometer is a d. The phase-shifting transformer is usually supplied by single-phase current.
polar type ac potentiometer – Electrical Engineer
Further references can be found at: These children deserve a space which is engaging and instructive, where they can feel a sense of adventure, exploration and surprise! In order to operate the galvanometer at its maximum sensitivity, provision is made to short the protective resistance when near the balance conditions. Circuit Globe All about Electrical and Electronics.
The single range potentiometer can be modified to include a second measuring range of lower value by adding two range resistors and a range switch.
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. A key and a protective resistance is used in the galvanometer resistance. Join our Mailing List by adding your email address below and be kept up to date with lots of information including:.
Now to measure unknown e.