Join 60,000+ competitive exam aspirants
or with email
Your Cart
Subtotal₹0
Total₹0
Examoogle • User • info@examoogle.com • EE-2024-8821
Chapter 1 of 12 • Page 1 of 248🔒 Protected PDF • Watermarked
Join 60,000+ competitive exam aspirants
No question text
1 to 1.5
.85 to .88 0.85 to 0.88
0.5 to 0.75
None of these
.85 to .88 0.85 to 0.88
Quick Summary: The value 0.85 to 0.88 represents the typical power factor (pf) range for induction motors when operating at full load under standard industrial conditions. Induction motors are inductive loads and always draw lagging reactive power from the supply system, resulting in a power factor less than unity.
The value 0.85 to 0.88 represents the typical power factor (pf) range for induction motors when operating at full load under standard industrial conditions. Induction motors are inductive loads and always draw lagging reactive power from the supply system, resulting in a power factor less than unity.
cos(ϕ)=SP — Definition of power factor as the ratio of real power to apparent power.
S=P2+Q2 — Relationship between apparent power, real power, and reactive power.
An induction motor operates on the principle of a rotating magnetic field inducing currents in the rotor. The magnetizing current required to establish the air-gap flux remains relatively constant, while the load-dependent active component increases with mechanical load. At full load, the ratio of real power (active) to apparent power (total) typically results in a power factor between 0.85 and 0.88.
Induction motors are inherently lagging loads due to the magnetizing current requirement.
Power factor is lowest at no-load conditions and improves as the motor is loaded towards its rated capacity.
A power factor range of 0.85-0.88 is standard for high-efficiency medium-sized induction motors at full load.
Low power factor in industrial plants leads to increased copper losses in distribution lines and reduced voltage regulation.
Improved efficiency at near-rated load
Optimized current rating for transmission cables
High reactive power consumption
Voltage drops due to lagging current
Industrial conveyor systems
Pump and fan drives
Compressors
At light loads, the power factor of an induction motor drops significantly because the magnetizing current remains dominant compared to the active current component.
Power factor correction capacitors are often installed in parallel with large motors to bring the power factor closer to unity.
B is correct — The power factor of a standard induction motor at full load typically falls within the range of 0.85 to 0.88.
Always remember that induction motor power factor is always lagging; unity or leading power factor is only achieved with specific equipment like synchronous condensers or capacitor banks.