Question

The current and power factor of a 3–\(\phi\) induction motor at no-load are respectively

• A. 1 to 2% of rated current and 0.2 lagging
• B. 30 to 40% of rated current and 0.2 lagging
• C. 2 to 6% of rated current and 0.8 lagging
• D. 30 to 40% of rated current and 0.8 lagging

Hint:

At no-load, current is high and power factor is poor due to dominance of magnetizing current.

Answer 1

The Correct Option is B

At no-load, a 3-\(\phi\) induction motor draws a significant amount of current (30–40% of rated) mainly to magnetize the core. The power factor is very low (0.1 to 0.3 lagging), hence 0.2 lagging is accurate.