4EE3A ELECTRICAL MEASUREMENTS (Common to EE and EX)
Unit 1
Measuring Instruments: Moving coil, moving iron, electrodynamic and induction instrumentsconstruction, operation, torque equation and errors. Applications of instruments for measurement of current, voltage, single-phase power and single-phase energy. Errors in wattmeter and energy meter and their compensation and adjustment. Testing and calibration of single-phase energy meter by phantom loading.
Unit 2
Polyphase Metering: Blondel's Theorem for n-phase, p-wire system. Measurement of power and reactive kVA in 3-phase balanced and unbalanced systems: One-wattmeter, two-wattmeter and three-wattmeter methods. 3-phase induction type energy meter. Instrument Transformers: Construction and operation of current and potential transformers. Ratio and phase angle errors and their minimization. Effect of variation of power factor, secondary burden and frequency on errors. Testing of CTs and PTs. Applications of CTs and PTs for the measurement of current, voltage, power and energy.
Unit 3
Potentiometers: Construction, operation and standardization of DC potentiometers– slide wire and Crompton potentiometers. Use of potentiometer for measurement of resistance and voltmeter and ammeter calibrations. Volt ratio boxes. Construction, operation and standardization of AC potentiometer – in-phase and quadrature potentiometers. Applications of AC potentiometers.
Unit 4
Measurement of Resistances: Classification of resistance. Measurement of medium resistances – ammeter and voltmeter method, substitution method, Wheatstone bridge method. Measurement of low resistances – Potentiometer method and Kelvin's double bridge method. Measurement of high resistance: Price's Guard-wire method. Measurement of earth resistance.
Unit 5
AC Bridges: Generalized treatment of four-arm AC bridges. Sources and detectors. Maxwell's bridge, Hay's bridge and Anderson bridge for self-inductance measurement. Heaviside's bridge for mutual inductance measurement. De Sauty Bridge for capacitance measurement. Wien's bridge for capacitance and frequency measurements. Sources of error in bridge measurements and precautions. Screening of bridge components. Wagner earth device.
Suggested Readings:
1. H.S. Kalsi, “Electronic Inst. & Measurement”, Tata Mc-Graw Hill.
2. Morris, “Electrical Measurements & Instrumentation”, ELSEVIER.
3. Bell, “Electronic Instrumentation and Measurement”, Oxford.
4. W.D. Cooper, “Electronic Inst. & Measurement Techniques”, Prentice Hall, India.
5. A.K. Sawhney, “Electrical & Electronic Measurement &Inst”, DhanpatRai& Sons.
6. E.W. Golding & F.C. Widdis, “Electrical Measurement & Measuring Instrument”, A.W. Wheeler.
7. Forest K. Harries, “Electrical Measurement”,Willey Eastern Pvt. Ltd. India.