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. 25.564 Ω. 2.781 Ω. 2.74 Ω. 2.241 Ω. 25.564 Ω. 2.781 Ω. 2.74 Ω. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a DC generator, if P be the number of poles and N be the rpm of the rotor, then frequency of magnetic reversals will be PN/3000. PN/60. PN/2. PN/120. PN/3000. PN/60. PN/2. PN/120. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Autotransformer makes effective saving on copper and copper losses, when its transformation ratio is equal to greater than one. less than one. approx to one. very low greater than one. less than one. approx to one. very low ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider a separately excited DC motor. If the field current is increased while the armature terminal voltage is held constant, then speed of the motor Increase. None of these. Decrease. Remains same. Increase. None of these. Decrease. Remains same. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Flashing of DC generator means None of these increasing flux density by providing extra ampere-turns in field. neutralization of residual magnetism. creation of residual magnetism by a DC source. None of these increasing flux density by providing extra ampere-turns in field. neutralization of residual magnetism. creation of residual magnetism by a DC source. 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. T2 ∝ P3. T ∝ √P. T is independent of P. T ∝ P. T2 ∝ P3. T ∝ √P. T is independent of P. ANSWER DOWNLOAD EXAMIANS APP
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