Electrical Machines A 500 V, 55 kVA single phase alternator has an effective resistance of 0.5 Ω. An excitation current of 10 A produces 200 A armature current on short circuit and an emf of 450 V on per circuit. The synchronous reactance will be 2.241 Ω. 2.781 Ω. 25.564 Ω. 2.74 Ω. 2.241 Ω. 2.781 Ω. 25.564 Ω. 2.74 Ω. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The speed of rotation of 5th harmonic component in the stator of an induction motor is (1 / 15) times the synchronous speed. (1 / 5) times the synchronous speed. 5 times the synchronous speed. 0.5 times the synchronous speed. (1 / 15) times the synchronous speed. (1 / 5) times the synchronous speed. 5 times the synchronous speed. 0.5 times the synchronous speed. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The back emf produced in a dc motor depends on P. P and Z. none of these. Z. P. P and Z. none of these. Z. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A commutator in DC machines can 1. provide half-wave rectification 2. Provide full-wave rectification 3. convert ac to dc 4. Convert dc to ac 5. provide controlled full-wave rectification From these, the correct answer is 2, 3 ,5 2, 3, 4 1, 2, 3 2, 3, 4, 5 2, 3 ,5 2, 3, 4 1, 2, 3 2, 3, 4, 5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a loaded DC generator, if the brushes are given a shift from the interpolar axis in the direction of rotation, then the commutation will improve with rise in terminal voltage. deteriorate with fall of terminal voltage. deteriorate with rise in terminal voltage. improve with fall of terminal voltage. improve with rise in terminal voltage. deteriorate with fall of terminal voltage. deteriorate with rise in terminal voltage. improve with fall of terminal voltage. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Neglecting all losses, the developed torque (T) of DC separately excited motor, operating under constant terminal voltage is reduced to its output power (P) as T ∝ √P. T is independent of P. T ∝ P. T2 ∝ P3. T ∝ √P. T is independent of P. T ∝ P. T2 ∝ P3. ANSWER DOWNLOAD EXAMIANS APP
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