Discussion:- 1. What do you understand by "armature- reaction"? Discuss the effect of armature reaction in an alternator when it is loaded with resistive, inductive and capacitive loads. 2. Give the value of voltage regulation for different power factors at full load current and interpret their values. .-----

Two shunt generators A and B operates in parallel and their load characteristicsmay be taken us straight lines. The voltage of the generator A falls from 240 V atno-load to 220 V at 200 A while that of B falls from 245 V at no load to 220 V at150 A. Determine the current which each machine supplies to a common load of300 A and the bus-bar voltage at this load.

32. An alternator requires an alternating current of 2.1 A to produce on short circuit its full-load current of 50 A. The same on open-circuit an emf of 320 V. The armature resistance is 1Ohms . Find the full-load percentage regulation with a lagging p.f. of 0.6 when terminal p.d. on load is 2000 V. A. 7.2% B. 28.8% C. 3.6% D. 14.4%