Electrical Machines Practice Test 9

1. Torque-slip characteristic of an induction motor is linear in the smaller slip values, because ___________

2. Energizing the transformer primary from a triangular wave voltage source makes the output voltage as __________

3. A 3-phase induction motor has full load efficiency of 0.7 and a maximum efficiency of 0.85. It is operated at a slip of 0.6 by reduced voltage method. The efficiency of the motor at this operating point is?

4. Which of the following machines can be used to place open slot winding?

5. The non linear magnetization curve of a practical transformer will introduce _____________

6. Consider a 2-winding transformer as below. If the switch is open then the emf induced across the secondary having transformation ratio of 2 is?

7. The flux involved in the emf equation of a transformer has __________

8. Identify the phasor diagram for an ideal transformer at no load.

9. There are two identical transformers A and B such that flux density applied to B is doubled. Then magnetizing current of B is?

10. If a 3-phase induction motor is fed from the rotor short circuiting the stator terminals, frequency of the current flowing in the short-circuited stator is?