In induction motors, the length of air gap in kept as small as mechanically possible is order to have

low power factor
high power factor
high over load capacity
any of the above

The correct answer is: B. high power factor

The air gap in an induction motor is the distance between the stator and rotor windings. The smaller the air gap, the stronger the magnetic field and the higher the power factor. A high power factor means that the motor is more efficient and uses less power.

The other options are incorrect because:

  • A low power factor means that the motor is less efficient and uses more power.
  • A high overload capacity means that the motor can handle more current without overheating.
  • None of the above options are the reason why the length of air gap in an induction motor is kept as small as mechanically possible.