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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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.
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 top of the instrument. The basic principle here is measuring an unknown voltage by comparing it with known voltage. Further references can be found at: When current start flowing from stators, the rotating field is developed around the rotor and due to it e.
If the reading does not agree, a second measurement must be made, again returning to a calibration check after completion. Circuit Globe All about Electrical and Electronics. By doing some adjustments in sliding contacts and rheostat, the whole circuit gets balanced and galvanometer reads zero at the balanced condition.
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.
Arrangements are provided for reversing the ammeter in order to eliminate the effect of stray fields. These children deserve a space which is engaging and instructive, where they can feel a sense of adventure, exploration and surprise!
Related pages What is Potentiometer? The slide wire type of potentiometer is not a practical form of construction.
The operation of the AC potentiometer is quite complicated as compared to the DC potentiometer. As it is necessary to have the splitphase circuit somewhere near the resonating point, it must be adjusted for changes of frequency.
It is an instrument designed to measure an unknown voltage by comparing it with a known voltage. The phase displacement of the rotor emf is equal to rotor movement angle from its original position and it is related to the stator supply voltage. Join our Mailing List by adding your email address below and be kept up poalr date with lots of information including: The most important difference between a d.
This potentiometer is provided with a double throw switch which allows the a.cc.potentiometer of either the standard cell or the unknown emf to be applied to the working circuit. Where as, AC potentiometer measures both the magnitude and phase of unknown voltage by comparing it with known reference. The main potentiometer current must be kept at some known constant value.
Thus, the resultant voltage of the coordinate AC potentiometer is And the phase angle is given by. This ammeter must read correctly with alternating and continuous currents. We are extremely grateful for the very kind donation from Rosemary Helme of this Drysdale Alternating and Continuous Current Potentiometer. Applications of AC Potentiometer Measurement of self-inductance. The higher voltage is measured by either using the volt box ratio or two capacitors in series with the 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. Leave a Reply Cancel reply Your email address will not be published. Drysdale for the measurement of alternating potentials. The following are the steps to be followed during a potentiometric measurement:.
These are adjusted until the A. The phase shifting transformer is connected to the potentiometer to vary the phase of the voltage on the current. 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.
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. The function of the series components is to maintain constant AC supply in the potentiometer by doing small adjustments in it.
In a phase-shifting transformer, there is a combination of two ring-shaped laminated steel stators connected perpendicularly to each other as shown in the figure. Join our Mailing List by adding your email address below and be kept up to date with lots of information including:. The first one is named as the in-phase potentiometer which is used to measure the in-phase factor of an unknown e. The following are the important factor which must be considered for their operation.
It has electrodynamometer type ammeter along with DC potentiometer and phase-shifting transformer which is operated by single phase supply. The phase-shifting transformer is usually supplied by single-phase current. Web Design by Pure Energy.
After the standardization has been completed the switch is thrown to the operate position, thus connecting the unknown e. The AC potentiometers are classified by the value measured by the potentiometer dial and scales. Connects Facebook Youtube Videos.
There is one dial switch with 15 steps, each having a precision resistor.