In a 3-phase power measurement by two wattmeter method the reading of one of the wattmeter was zero. The power factor of the load must be
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Electrical Engineering · all questionsElectrical Machine Design
Electrical Machine Design
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Wattmeter cannot be designed on the principle of
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To measure a resistance with the help of a potentiometer it is
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A Weston synchronoscope is a
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The density of hydrogen is _____ times the density of air.
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In D.C. machines the width of the duct is usually
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The efficiency of a machine should be as ______ as possible to reduce the operating cost.
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Which of the following methods is used for air cooling of turbo-alternators ?
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In a Weston frequency meter, the magnetic axes of the two fixed coils are
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A practical formula for determining the thickness of insulation between low voltage and high voltage windings is
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A current density of _________ is used for large power transformers with forced circulation of oil or with water cooling coils.
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The resistance in the circuit of the moving coil of a dynamometer wattmeter should be
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_______ brushes are fragile and cause excessive wear of commutator,
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To avoid the effect of stray magnetic field in A.C. bridges we can use
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It is required to measure the true open circuit e.m.f. of a battery. The best device is
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Hydrogen has a heat transfer co-efficient _____ times that of air
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The thermal conductivity of hydrogen is ______ times that of air
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The design of mechanical parts is particularly important in case of _____ speed machines.
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A voltage of about 200 V can be measured
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Which of the following is measured by using a vector voltmeter ?
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