DRYSDALE POTENTIOMETER PDF
The Potentiometer is an instrument which measures unknown voltage by balancing it with a known voltage. The known source may be DC or. Definition of DRYSDALE POTENTIOMETER: An ac potentiometer of the polar type, comprising a phase-shifting transformer and resistive voltage divider. Definition: The potentiometer which is used for measuring the phase and the magnitude of the unknown emf by comparing it with the known emf such type of.
|Published (Last):||4 June 2017|
|PDF File Size:||17.96 Mb|
|ePub File Size:||7.34 Mb|
|Price:||Free* [*Free Regsitration Required]|
The known source may be DC or AC. 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. Measurements of Self Reactant of a Coil — The standard reactance is placed in series with the coil whose reactance is to be measured. 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.
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 potentiometer – is then thrown on to the A. The first one is potentuometer as the in-phase potentiometer which is used to measure the in-phase factor of an 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.
In a phase-shifting transformer, there is a combination of two ring-shaped laminated steel stators connected perpendicularly to each other as drysdalle in the figure. Arrangements are provided for reversing the ammeter in order to eliminate the effect of stray fields. Thus, the voltage and current may vary at different power factor.
The reading of a sensitive dynamometer type ammeter in the main circuit is noted. 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 following are the important factor which must be considered for their operation. Hence the value of the unknown emf is known.
Further references can be found at: In this potentiometer, the magnitude of the unknown voltage is measured from one scale, and its phase angle is directly on the second scale. Other Applications — The AC potentiometer is used for engineering measurement in which the accuracy of 0. The phase shifting transformer is connected to the potentiometer to vary the phase of the voltage on the current. The function of the series components is to maintain constant AC supply in the potentiometer by doing small adjustments in it.
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.
Now to measure unknown e. Circuit Globe All about Electrical and Electronics. Drysdale’s Alternating pitentiometer Continuous Current Potentiometer. These are adjusted until the A.
The AC potentiometer may be broadly classified as. The indicator for low frequencies is a vibration galvanometer which must be closely tuned to resonate to the frequency of the circuit. The operation of the AC potentiometer is quite complicated as compared to the DC potentiometer. The working principle of the AC potentiometer is same as that of the DC potentiometer, i. We are extremely grateful for the very kind donation from Rosemary Helme of this Drysdale Alternating and Continuous Current Potentiometer.
It gives the accurate results in magnetic testing and precise testing of instrument transformers. The higher voltage is measured by either using the volt box ratio or two capacitors in series with the potentiometer. And when both of them are equal the galvanometer indicates the null point. Further, the phase relation between the circuit to be measured and that supplying the potentiometer may have any value from to There are two types of AC potentiometers: The phase-shifting transformer is usually supplied by single-phase current.
For higher frequencies a telephone may be used. The working phenomenon of DC potentiometer and AC potentiometer is same. The rotor has a winding on it which supplies the potentiometer current.