Electrical Machines In a dc machine 72 number of coils are used. Find the number of commutator segments required? 37 36 74 72 37 36 74 72 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 220 ,V 15 , kW 100 rpm shunt motor with armature resistance of 0.25 , W has a rated line current of 68 A and a rated field current of 2.2 A. The change in field flux required to obtain a speed of 1600 rpm while drawing a line current of 52.8 A and a field current of 1.8 A is 36.36% increase 36.36% decrease 18.18% increase 36.36% increase 36.36% increase 36.36% decrease 18.18% increase 36.36% increase ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The result of slip test on a 3-phase, 20 KVA, 400 V, 50 Hz connected salient pole alternator is given below- Phase value: Vmax = 100 V, Vmin = 96 V, Imax = 10 A and I min = 7 A. The direct and quadranature axis reactances are respectively 8.248 and 5.54 Ω. 14.28 and 5.54 Ω. 14.28 and 9.60 Ω. 8.248 and 9.60 Ω. 8.248 and 5.54 Ω. 14.28 and 5.54 Ω. 14.28 and 9.60 Ω. 8.248 and 9.60 Ω. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What is the necessity of copper brushes in a dc motors? To convert alternating supply current to direct current. To increase the flux cutting by the rotor. None of these. To absorb the mechanical shocks produced during running condition. To convert alternating supply current to direct current. To increase the flux cutting by the rotor. None of these. To absorb the mechanical shocks produced during running condition. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If Pi and Pc represent core and full load copper loss respectively, the maximum KVA delivered to load corresponding to maximum efficiency is equal to rated KVA is Pi/Pc (Pi/Pc)2 Pc/Pi √(Pi/Pc) Pi/Pc (Pi/Pc)2 Pc/Pi √(Pi/Pc) ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In DC machines, the interpoles are provided both (B) and (C). to counteract demagnetizing effect of armature mmf in commutating zone. to make commutation spark less. to counteract the reactance voltage and the cross-magnetizi both (B) and (C). to counteract demagnetizing effect of armature mmf in commutating zone. to make commutation spark less. to counteract the reactance voltage and the cross-magnetizi ANSWER DOWNLOAD EXAMIANS APP
EXAMIANS