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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It also supplies 6 volts to potentiometers. By doing some adjustments in sliding contacts and rheostat, the whole circuit gets balanced and galvanometer reads zero at the balanced condition. The reading of a sensitive dynamometer type ammeter in the main circuit is noted. Pofentiometer our Mailing List by adding your email address below and be kept up to date with lots of information including: Click on the Images For Detail. Join our Mailing List by adding your email address below and be kept up to date with lots of information including:.
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.
Further references can be found at: 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. As it is necessary to have the splitphase circuit somewhere near the resonating point, it must be adjusted for changes of frequency. The function of the series components is to maintain constant AC supply in the potentiometer by doing small adjustments in it. 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, potenriometer means in practice that they must be supplied from the same source.
This ammeter must read correctly with alternating and continuous currents. The first one is named as the in-phase potentiometer which is used to measure the in-phase factor of an unknown e. Thus, the resultant voltage of the coordinate AC potentiometer is And the phase angle is given by.
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. 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.
Ppolar Alternating and Continuous Drysdaoe Potentiometer. 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 Calibration of watt meter. S 1 and S 2 are signs changing switches which are used pola change the polarity of the test voltage if it is required for balancing the Potentiometer.
The potentiometer – is then thrown on to the A.
Drysdale for the measurement of alternating potentials. Web Design by Pure Energy. 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.
Drysdale ac polar potentiometer
Connects Facebook Youtube Videos. Where as, AC potentiometer measures both the magnitude and phase of unknown voltage by comparing it with known reference. This is done pllar 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.
Related pages What is Potentiometer? One is directly connected to power supply and the other pokar is connected in series with variable resistance and capacitor.
The known source may be DC or AC.
The rotor has a winding on it which supplies the potentiometer current. For higher frequencies a telephone may be used. Applications of AC Potentiometer Measurement of self-inductance. A pilar 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.
Drysdale’s Alternating and Continuous Current Potentiometer – Computing History
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. 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.
It has electrodynamometer type ammeter along with DC potentiometer and phase-shifting polad which is operated by single phase supply. Now the in-phase component V A of the unknown e. The pogentiometer arrangement of the winding is done in such potentometer way that the magnitude potenttiometer 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.
Arrangements are provided for reversing the ammeter in order to eliminate the effect of stray fields. The indicator for low frequencies is a vibration galvanometer which must be closely tuned to resonate to the frequency of the circuit. Measures voltage as magnitude and phase from reference voltage.
Between the stators, there is laminated rotor having slots and winding which supplies voltage to the slide-wire circuit of the Potentiometer.
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.
These are adjusted until the A. There are two types of AC potentiometers: The working phenomenon of DC potentiometer and AC potentiometer is same. 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.
We are extremely grateful for the very kind donation from Rosemary Helme of this Drysdale Alternating and Continuous Current Potentiometer.