Related Questions

A synchronous motor installed at the receiving end substation operates with such an excitation that it takes power at lagging power factor. Now if the applied voltage of the synchronous motor goes down, the power factor of the synchronous motor will
A remain same
B go down
C improve
D none of the above
A single phase transformer has a maximum efficiency of 90% at full load and unity power factor. Efficiency at half load at the same power factor is -
A 87.8%
B 86.7%
C 88.26%
D 88.9%
In a D.C. shunt motor, under the conditions of maximum power, the current in the armature will be
A Almost negligible
B Rated full-load current
C Less than full-load current
D More than full-load current
Efficiency of power transfer when maximum transfer of power c xerosis
A 100%
B 80%
C 75%
D 50%
There is a certain pressure ratio (optimum) for a gas turbine at which its thermal efficiency is maximum. With increase in turbine temperature, the value of pressure ratio for the peak efficiency would
A Remain same
B Decrease
C Increase
D None of the above
The condition for maximum power in case of D.C. motor is
A Back e.m.f. = 2 × supply voltage
B Back e.m.f. = $$\frac{1}{2}$$ × supply voltage
C Supply voltage = $$\frac{1}{2}$$ × back e.m.f.
D Supply voltage = back e.m.f.
The ratio of the indicated power to the shaft power or brake power of the motor or engine required to drive the compressor, is called
A Compressor efficiency
B Volumetric efficiency
C Isothermal efficiency
D Mechanical efficiency
According to maximum power transfer theorem, the maximum power is absorbed by one network from another network when
A The impedance of one of the networks is half that of the other
B The impedance of one is the complex conjugate of the other
C The impedance of one is equal to that of the other
D None of the above
The power factor of an induction motor under no-load conditions will be closer to
A 0.2 lagging
B 0.2 leading
C 0.5 leading
D unity
Of the 120 households in an area, 55 have cars, 35 have motor bikes, and 20 have both cars and motor bikes. How many of the households in the area have neither cares nor motor bikes?
A 110
B 90
C 50
D 30

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