Induction Motor

Important Formulae to remember


Induction Motor

Induction Motor Problems

  1. The frequency of the EMF in the stator of a 4 pole induction motor is 50 Hz and in the rotor is 1.5 Hz. What is the slip and what speed is the motor running?
  2. A 3 ∅ induction motor with 4 poles is supplied from the alternator having 6 poles running at 1000 rpm. Calculate synchronous speed of the induction motor its speed when slip is 0.04 and frequency of the rotor EMF when the speed is 600 rpm
  3. A 3∅, 6 pole, 50 Hz Induction motor has a slip of 1% at no load and 3% at full load. Determine (i)Synchronous speed, (ii)No load speed, (iii)Full load speed, (iv)Frequency of rotor current at stand still (v)Frequency of rotor current at full load
  4. An 8 pole 3∅ alternator runs at 750 rpm and supplies power to 6 pole 3∅ induction motor which runs at 970 rpm. What is the slip of the induction motor?
  5. A 4 pole, 3300V, 50 Hz, Induction motor runs at rated frequency and voltage. The frequency of the rotor currents is 2.5 Hz. Find slip and running speed
  6. A 4 pole, 3∅, Induction motor operates from a supply whose frequency is 50Hz. Calculate (i) Synchronous speed (ii) The speed of the rotor when the slip is 0.04 (iii) The frequency of the rotor current when the slip is 0.03 (iv) The frequency of the rotor current at standstill.
  7. What is the slip speed, slip and at what speed rotor runs if the frequency of the EMF in the stator of a 4 pole, 3∅ Induction motor is 50 Hz and in the rotor is 1.5 Hz?
  8. A 3∅, 4 pole, 400 V, 50 Hz Induction motor runs with a slip of 4%, find the rotor speed and frequency
  9. A 10 pole induction motor supplied by a 6 pole alternator which is driven at 1200 rpm. If the motor runs at slip of 3% what is its speed?
  10. If a 6 pole Induction motor is supplied from a 3∅, 50 Hz supply has a rotor frequency of 2.3 Hz, Calculate (i) Percentage slip (ii) Speed of the motor


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