Test Your Concept :
Subject : MACHINES
Topic : Synchronous Machines
Q : A synchronous generator connected to an infinite bus is overexcited. Considering only the reactive power, from the point of view of the system, the machine acts as
A. a capacitor
B. an inductor
C. a resistor
D. as RL circuit
ANSWER : B
Solution : An overexcited synchronous generator delivers reactive power to load and operates at lagging power factor.
Q : A 3-phase synchronous machine is synchronized with infinite bus. Now the prime-mover is disconnected from synchronous machine. with this, the synchronous machine would.
A. Work as a synchronous motor at a leading p.f.
B. Work as a synchronous motor at a lagging p.f.
C. Work as a 3-phase induction motor at a lagging p.f.
D. stop
ANSWER : A
Solution : When prime-mover is removed. Then synchronous alternator will works as a synchronous motor and operate at a leading p.f to operating in magnetizing mode.