The injected e.m.f in the rotor of an induction motor is of
- A. The same frequency as slip frequency
- B. The same phase as the rotor e.m.f
- C. A high value for satisfactory speed control
- D. The same phase as rotor e.m.f and a high value for satisfactory speed control.
Answer: A. The same frequency as slip frequency
Explanation: Injected rotor emf must be at slip frequency (can be in phase, anti-phase or quadrature).