Module 1
Principle of measuring instruments: Classification – indicating, recording and integrating instruments – Torque acting on the moving system – deflecting torque – methods of production – controlling torque – spring and gravity control – damping torque – electromagnetic and air friction damping.
Constructional features of instruments – torque to weight ratio of the moving system – basic theory of instruments – characteristics – damping coefficient – under damped – over damped and critically damped and critically damped instruments.
Module 2
Permanent magnet moving coil instruments: – Ammeters and Voltmeters – Torque relationship – Milliammeters and voltmeters – shunt and multipliers – sensitivity – multimeters.
Moving iron instruments: Attraction and Repulsion types – constructional features – Ammeters and Voltmeters – Errors and Compensation.
Module 3
Electrodynamometer instruments: Ammeters, Voltmeters and Watt meters – Sensitivity – Torque to weight ratio – methods of connection of current and potential coils- Errors and compensation – low power factor wattmeters – single phase wattmeters.
Induction type instruments: Wattmeters and energy meters – single phase and three phase – constructional features – Theory of operation – Errors and compensation – creep – maximum demand meters – Trivector meters.
Module 4
Rectifier Instruments: Principle of operation – Electrostatic instruments – voltmeters – characteristics, applications.
Electronic voltmeters – basic DC voltmeters – basic AC voltmeter using rectifier – basic electronic multi meter – function generator – RLC meter.
Cathode ray Oscilloscope: Principle – Application – Measurement of Voltage, current, phase and frequency. Multi-channel oscilloscopes – principle of operation and uses.
Module 5
Instruments for phase, frequency, speed, stroboscopic methods – Resonance frequency meters – Power factor meters – Synchroscope – phase sequence indicators.
Symbols for instruments – Indian standards specifications Grading of Instruments – Classification.
References
Electrical Measurements and Measuring Instruments – Golding E.W, Wheeler and Co., 1991.
Electrical and Electronic Instrumentation and Measurements – Sawhney A.K, Dhanpat Rai and Co., 1992.
Modern Electronic Instrumentation and measurement Technique – Albert D. Helfrick and William D. Cooper, PHI, 1992.
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