Join 60,000+ competitive exam aspirants
or with email
Your Cart
SubtotalтВ╣0
TotalтВ╣0
Examoogle тАв User тАв info@examoogle.com тАв EE-2024-8821
Chapter 1 of 12 тАв Page 1 of 248ЁЯФТ Protected PDF тАв Watermarked
Join 60,000+ competitive exam aspirants
In single-phase induction motor ┬╖ What is the power factor for the output watt of 750?
0.46
0.51
0.62
0.65
0.65
In a single-phase induction motor, the power factor is inherently low compared to three-phase motors due to the high magnetizing current required to produce the rotating magnetic field from a single-phase supply ┬╖ For a motor with a rated output of 750 Watts (1 HP class), the operating power factor at full load typically falls in the range of 0.60 to 0.70.
In a single-phase induction motor, the power factor is inherently low compared to three-phase motors due to the high magnetizing current required to produce the rotating magnetic field from a single-phase supply ┬╖ For a motor with a rated output of 750 Watts (1 HP class), the operating power factor at full load typically falls in the range of 0.60 to 0.70.
P=VтЛЕIтЛЕcos╧Х тАФ Real power formula
cos╧Х=VтЛЕIPтАЛ тАФ Power factor calculation
The single-phase induction motor operates on the principle of a pulsating magnetic field created by the stator winding ┬╖ Because the motor lacks a self-starting torque, auxiliary windings or centrifugal switches are used ┬╖ The magnetizing component of the stator current, which is necessary to maintain the air-gap flux, is large and lags the voltage by nearly 90┬░, resulting in a low power factor.
Single-phase induction motors have low power factors due to high magnetizing current requirements.
The power factor improves slightly as the motor load increases toward its rated value.
Small fractional horsepower motors (like 750W) generally exhibit power factors between 0.55 and 0.70.
Excessive magnetizing current is required to establish the pulsating flux.
Simple construction and low cost
Easy to maintain due to fewer components
Low power factor
Lower efficiency compared to three-phase motors
Domestic fans and refrigerators
Small centrifugal pumps and compressors
AтВЗтВЕтВАW (1 HP) motor typically draws more apparent power (VA) than active power (W) due to inductive reactance.
Option A (0.46) and B (0.51) are common for unloaded or lightly loaded conditions.
Option D (0.65) is a standard industrial benchmark for a loaded 750W single-phase induction motor.
D is correct тАФ The power factor for a standard 750W single-phase induction motor at full load is approximately 0.65.
Always remember that single-phase motors are inherently less efficient and have poorer power factors than three-phase equivalents because of the need for auxiliary starting methods and air-gap flux generation.