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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There are two types of AC potentiometers: As it is necessary to have the splitphase circuit somewhere near the resonating point, it must be adjusted for changes of frequency. 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. 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.
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.
Related pages What is Ptoentiometer 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.
There is a provision on the scale that it could read phase angle up to 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.
For higher frequencies a telephone may be used.
Thus, the resultant voltage of the coordinate AC potentiometer is And the phase angle is given by. Drysdale’s Alternating and Continuous Current Potentiometer. By doing some adjustments in sliding contacts and rheostat, the whole circuit gets balanced and galvanometer reads zero at the balanced condition. Please be assured that any amount you feel able to donate will make an immediate and significant impact. 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 first one is named as the in-phase potentiometer which is used to measure the in-phase factor of an unknown e.
Connects Facebook Youtube Videos. Between the stators, there is laminated rotor having slots and winding which supplies voltage to the slide-wire pokar of the Potentiometer. Now to measure unknown e. Join our Mailing List by adding your email address below and be kept up to date with lots of information including:. The main potentiometer current must be kept at some known constant value.
Drysdale’s Alternating and Continuous Current Potentiometer – Computing History
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 known source may be DC or AC. 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.
The potentiometer – is then thrown on to the A.
Where as, AC potentiometer measures both the magnitude and phase of unknown voltage by comparing it with known reference. Drysdale for the measurement of alternating potentials.
Web Design by Pure Energy. Further, the phase relation between the circuit to be measured and that supplying the potentiometer may have any value from to 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.
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. 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. Arrangements are provided for reversing the ammeter in order to eliminate the effect of stray fields.
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.
The “balance” is obtained by successive approximation of drysfale usual adjustment of the potentiometer contacts dial and slide wire reading and of the phase-shifting transformer until the indicator shows no deflection.
Join our Mailing List by adding your email address below and potejtiometer kept up to date with lots of information including: The phase displacement of the rotor emf is equal to rotor movement potentuometer from its original position and it is related to the stator supply voltage.
Further references can be found at: The working phenomenon of DC potentiometer and AC potentiometer is same.