Induction Motor Questions Part 1

Induction Motor Questions Part 1 With brief explanator answers

What Is An Induction Motor

An induction motor sometimes short known as IM is a type of asynchronous AC motor in which electric power is supplied to the rotating device by means of electromagnetic induction.

Why air gap between stator and rotor of 3 phase induction motor is kept as short as conceivable

The air gap between stator and rotor is kept small in order to ensure that leakage reactances are kept small as well as to ensure that mutual flux is produced with minimum exciting current.

What are some advantages of wound rotor motors over squirrel cage motor

  1. Squirrel cage motors have been advantageous over wound rotor motor because:
  2. They have smooth acceleration under heavy loads
  3. They don’t have abnormal heating during starting
  4. They have good running characteristics after cutting rotor resistance
  5. They have high starting torque
  6. They have low starting current
  7. They have advantage of speed adjustment

A fully loaded 3 phase induction motor doesn’t possess a very high-power factor. What is the reason behind this

With an increase in load, the increasing active component of current results in a higher power factor. However, the large value of magnetizing current due to the high reluctance of the magnetic circuit (which is majorly due to the air gap) keeps the power factor lower than 0.85.

What happens if one line conductor of 3 phase induction motor is opened

The motor will continue to run as single-phase motor. Current drawn from the remaining two conductors will increase and in turn, the motor will be overheated. Finally, the thermal relays for protecting the motor will play their role in tripping the circuit breaker and disconnecting the motor from the power line.

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