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
Answer: Option A
Solution (By Examveda Team)
Under no-load conditions, an induction motor primarily draws a small active power and a large magnetizing current.The magnetizing current is highly reactive in nature, causing the motor to operate at a very low power factor.
Since the magnetizing current lags the applied voltage, the power factor is lagging and typically very low, around 0.2 lagging.
The power factor cannot be leading because an induction motor does not produce reactive power but rather consumes it.
The power factor is also far from unity under no-load conditions due to the dominance of magnetizing current.
Hence, the correct answer is 0.2 lagging (Option A).
This Question Belongs to Electrical Engineering >> Transformers
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Comments (2)
The purpose of providing an iron core in a transformer is to
A. provide support to windings
B. reduce hysteresis loss
C. decrease the reluctance of the magnetic path
D. reduce eddy current losses
A good voltage regulation of a transformer means
A. output voltage fluctuation from no load to full load is least
B. output voltage fluctuation with power factor is least
C. difference between primary and secondary voltage is least
D. difference between primary and secondary voltage is maximum
If the percentage impedances of the two transformers working in parallel are different, then
A. transformers will be overheated
B. power factors of both the transformers will be same
C. parallel operation will be not possible
D. parallel operation will still be possible, but the power factors at which the two transformers operate will be different from the power factor of the common load
An ideal transformer will have maximum efficiency at a load such that
A. copper loss = iron loss
B. copper loss < iron loss
C. copper loss > iron loss
D. none of the above
Because of the air gap, the reluctance of the magnetic circuit of the three-phase induction motor is very high.Consequently, the current drawn by the motor on no load is largely magnetizing current, the no-load current is lagging the applied voltage by a large angle.For this reason, the power factor of a lightly loaded (or no load) three-phase induction motor is very low about 0.2 to 0.3 lagging
Explain plz