3EE5-ELECTRICAL MEASUREMENTS |
Units: I-Measuring Instruments: |
Moving coil, moving iron, electrodynamic and induction
instruments-construction, 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.
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Units: II-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. |
Units: III-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.
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Units: IV-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.
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Units: V-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.
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