Compiled by: Sr. Lect. Prachi Dewan
LIST OF EXPERIMENTS
(Electrical Science Lab-I)
Branch:- EEE /ECE
1. Introduction to various Basic Instruments of Electrical Science 2. To verify Superposition Theorem.
3. To verify Thevenin Theorem and find out Thevenin’s Equivalent circuit using DC Sources. 4. To verify Maximum Transfer Theorm for D.C source.
5. To study R-L-C series circuit and draw its phasor diagram. 6. Measurement of energy and calibration of single phase Energy meter with Wattmeter. 7. To perform open circuit test and short circuit test on single phase transformer. 8. Load test on a single phase transformer regulation and efficiency.
AIM: Introduction to various Basic Instruments of Electrical Science
OBJECTIVE: Introduction to various Supply Systems, Ammeter, Voltmeter, Wattmeter, Energy meter, Tachometer, Rheostat, Loading Devices, Transformer.
Apparatus Required: Demonstration of various instruments like Ammeter, Voltmeter, Wattmeter, Energy meter, Tachometer, Rheostat, Various Capacitors, Various Resistors, AC and DC Power Supply.
Theory of Experiment:
Ammeters are employed for measuring current in a circuit and connected in series with the circuit. As ammeter is connected in series, the voltage drop across ammeter terminals should be as low as possible. This requires that the resistance of the ammeter should be as low as possible. The current coil of Ammeter has low current carrying capacity whereas the current to be measured may be quite high. For this reason a low resistance is connected in parallel to the current coil. b) VOLTMETER
Voltmeters are employed to measure the potential difference across any two points of the circuit these are connected in the parallel to the circuit. The resistance of voltmeter is kept very high by connecting a high resistance in series of the voltmeter with the current coil of the instrument. The actual voltage drop across the current coil of the voltmeter is only a fraction of the total voltage applied across the voltmeter which is to be measured. There are three types of ammeters and voltmeters generally used : a) Moving coil type
b) Moving iron type
c) Electronic Voltmeter
The measurement of real power in AC circuits is done by using an instrument using Wattmeter. The real power in AC circuits is given by expression VI cosø where, cosø is power factor.
A wattmeter is comprises of two coils namely current coil and pressure coil. The current coil is connected in series with the load and the pressure coil is connected across the load.Wattmeters are available in dual range for voltages as well as for current .g. 5/10A,000/400V.In order take down the correct reading a multiplying factor is used. These multiplying factors are according to the range of instrument
Energy meter is an instrument which is used o measure he consumption of electric energy in an AC circuits. It measures energy in KWH. The principle of operation of an energy meter is just like wattmeter except that due to power through the meter ,a disc rotates. The number of revolution made by the disc is counted.
Tachometer is an instrument to measure the speed in r.p.m..The speed of a rotating shaft is measured by inserting he tapered projected of the tachometer into the tapered hole in a rotating shaft of which speed is to be measured.
Rheostats are made up of high resistivity material like nickel-chromium iron alloy closely wound over a circular tube.These are available both in single tube and double tube.Inter-turn insulation is provided to avoid...
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