If an induction machine run at above synchronous speed, it can act as (GATE-EE)

a.a synchronous motor

b.an induction generator

c.an induction motor

d.non of these

ANS: C

Explanatory answer: 

•  when an iduction motor is made to run above synchronous  speed (Ns) by  using a prime mover,it  work as induction generator.
• Ns<N, hence the slip becomes negative that induction machine takes electrical power and delievers mechanical power