CL wadhwa bits solutions (115-119)

Lesson 20 of 21 • 31 upvotes • 6:42mins

Anvesh Sameer

115. If a synchronous machine is underexcited it takes lagging vars from the system when it is operated as a: (a) Synchronous motor (b) Synchronous generator (c) Synchronous motor as well as generator (d) None of the above. 116. A synchronous machine has higher capacity for: (a) Leading p.f. (b) Lagging p.f. (c) It does not depend upon the p.f. of the machine (d) It depends upon the p.f. of the load. 117. A machine designed to operate at full load is physically heavier and is costlier if the operating p.f. is: (a) Lagging (b) Leading (c) The size and cost do not depend on p.f. 118. For the same voltage boost, the reactive power capacity is more for a: (a) Shunt capacitor (b) Series capacitor (c) It is same for both series and shunt. 119. A synchronous phase modifier as compared to a synchronous motor used for mechanical loads has: (a) Larger shaft and higher speed (b) Smaller shaft and higher speed (c) Larger shaft and smaller speed (d) Smaller shaft and smaller speed.