A synchronous machine with low value of short-circuit ratio has lower stability limit.

Answer : The duration of sudden short-circuit test on a synchronous motor is usually about one second.

Description : The ratio of full -load volt-amperes to short-circuit volt-amperes is equal to :

Answer : The ratio of full -load volt-amperes to short-circuit volt-amperes is equal to : Z (p.u)

Description : The armature current on symmetrical 3 phase short circuit of a synchronous machine (salient pole) (A) has q -axis current only (B) has d -axis current only (C) has both d and q axis currents (D) cannot be divided between q and d axis currents

Answer : The armature current on symmetrical 3 phase short circuit of a synchronous machine (salient pole) has d -axis current only

Description : In an AC. circuit, a low value of kVAR compared with kW indicates?

Answer : In an AC. circuit, a low value of kVAR compared with kW indicates high power factor.

Answer : The operating speed of a synchronous motor can be changed to new fixed value by changing frequency.