When the e.m.f. being measured is equal to the potentiometer voltage, the amplifier output Since polar potentiometer was developed by Dr. C.V. Drysdale , it is. Dr. C.V. Drysdales Alternating and Continuous Current Potentiometer The instrument comprises the standard Tinsley DC potentiometer of the time, with a phase. In a.c. potentiometers, another requirement is the control of stray e.m.f.s in fields Being a polar type, Drysdale – Tinsley a.c. potentiometer measures unknown.
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To obtain the necessary field distribution a split-phase scheme is used, part of the excitation being provided by a circuit containing a condenser and a resistance in series.
Applications of AC Potentiometer Measurement of self-inductance. We are extremely grateful for the very kind donation from Rosemary Helme of this Drysdale Alternating and Continuous Current Potentiometer. Join our Mailing List by adding your email address below and be kept up to date with lots of information including:. The working phenomenon of DC potentiometer and AC potentiometer is same. In order to obtain a balance, as indicated by the detecting instrument, it must be possible to give to the potentiometer current any phase displacement relative to that of the potential supplying it.
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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. The known source may be DC or AC. S 1 and S 2 are signs changing switches which are used to change the polarity of the test voltage potdntiometer it is required for balancing the Potentiometer.
Drysdale for the measurement of alternating potentials. Click on the Images For Detail. Further references can be found at: There are two types of AC potentiometers: These children deserve a space which is engaging and instructive, where they can feel a sense of adventure, exploration and surprise! Calibration of watt meter. But there is one major difference between their measurements, DC potentiometer only measures the magnitude of the unknown voltage.
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.
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 drysdal AC measuring and supply voltages.
Where as, AC potentiometer measures both the magnitude and phase of unknown voltage by comparing it with known reference. Polar type Potentiometer In such type of instruments, drysdzle separate scales are used to measure magnitude and phase angle on some reference of the unknown e.
It has electrodynamometer type ammeter along with DC potentiometer and phase-shifting transformer which is operated by single phase supply.
Web Design by Pure Energy. 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 reading of a sensitive dynamometer type ammeter in the main circuit is noted.
Drysdale’s Alternating and Continuous Current Potentiometer. One is directly connected to power supply and the other one is connected in series with variable resistance and capacitor. Arrangements are provided for reversing the ammeter in order to eliminate the effect of stray fields. There is potentioometer provision on the scale that it could read phase angle up to By doing some adjustments in sliding contacts and rheostat, the whole circuit gets balanced and galvanometer reads zero at the balanced condition.
For higher frequencies a telephone may be used. Since opening at the end pilarover 5, children have visited the Centre. Between the stators, there is laminated rotor having slots and winding which supplies voltage to the slide-wire circuit of the Potentiometer. When current start flowing from stators, the rotating field is developed around the rotor and due to it e. The indicator for low frequencies is a vibration galvanometer which must be closely tuned to resonate to the frequency of the circuit.
These are adjusted until the A. The phase-shifting transformer is usually supplied by single-phase current. The potentiometer – is then thrown on to the A.
The first one is named as the in-phase potentiometer which is used to measure the in-phase factor of an unknown e. Related pages What is 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 drsydale affect the phase angle and it can be read on the pklar fixed on the top of the instrument.
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. There are two step-down transformers T 1 and T 2 which isolate potentiometer from the line and give an earthed screens protection between drysale winding. Now the in-phase component V A of the unknown e. Connects Facebook Youtube Videos.
The main potentiometer current must be kept potfntiometer some known constant value. 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.
As the vibration galvanometer has also to be adjusted for such changes, it is necessary to have a source of a very steady frequency and voltage for satisfactory working. Thus, the resultant voltage of the coordinate AC potentiometer is And the phase angle is given by.
Join our Mailing List by adding your email address below and be kept up to date with lots of information including: Coordinate type Potentiometer In coordinate AC potentiometertwo separate potentiometers are caged in one circuit as shown in the figure. It also supplies 6 volts to potentiometers. Further, the phase relation between the circuit to be measured and that supplying the potentiometer may have any value from to The rotor has a winding on it which supplies the potentiometer current.
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. As it is necessary to have the splitphase circuit somewhere near the resonating point, it must be adjusted for changes of frequency.
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.
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