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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The potentiometer – is then thrown on to the A. Further references can be found at: Since opening at the end ofover 5, children have visited the Centre.
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. As it is necessary to have the splitphase circuit somewhere near the resonating point, it must be adjusted for changes of frequency. One is directly connected to power supply and the other one is connected in series with variable resistance and capacitor. There are two types of AC potentiometers: Arrangements are provided for reversing the ammeter in order to eliminate the effect of stray fields.
Drysdale’s Alternating and Continuous Current Potentiometer. Please be assured that any amount you feel able to donate will make an immediate and significant impact. Between the stators, there is laminated rotor having slots and winding which supplies voltage to the slide-wire circuit of the Potentiometer. There are two step-down transformers T 1 and T 2 which isolate potentiometer from the line and give an earthed screens protection between the winding. The first one is named as the in-phase potentiometer which is used to measure the in-phase factor of an unknown e.
But there is one major difference between their measurements, DC potentiometer only measures the magnitude of the unknown voltage.
The indicator for low frequencies is a vibration galvanometer which must be closely tuned to resonate to the frequency of the circuit.
The phase-shifting transformer is usually supplied by single-phase current. Now to measure unknown e.
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.
A rotation of the rotor of the phase-shifting transformer through o has the effect of producing a phase shift of the same value, and a pointer on the rotor axis indicates the phase angle on a suitably divided scale. Where as, AC potentiometer measures both the magnitude and phase of unknown voltage by comparing it with known reference.
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The reading of a sensitive dynamometer type ammeter in the main circuit is noted. 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 drrysdale shows no deflection. When current start flowing from stators, the rotating field is developed around the rotor and due to it e.
Join our Mailing List by adding your email address below and be kept up to date with lots of information including:. 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 function of the series components is to maintain constant AC potentioneter 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. Coordinate type Potentiometer In coordinate AC potentiometertwo separate potentiometers are caged in one circuit as shown in the figure.
Further, the phase relation between the circuit to be measured and that supplying the potentiometer may have any value from to 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.
The phase displacement of the rotor emf is equal potenntiometer rotor movement angle from its original position and it is related to the stator supply voltage. Web Design by Pure Energy.
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.
Measures voltage as magnitude and phase from reference voltage. 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.