Electrical Machines A 5 KVA transformer has a turns ratio of N1/N2 = 10. The impedance of primary winding is 3+j5 ohms while that of secondary winding is 0.5+j0.8 ohms. The impedance of transformer when referred to primary will be 8+j13 ohms 3.5+j5.8 ohms 53+j85 ohms 3.05+j5.08 ohms 8+j13 ohms 3.5+j5.8 ohms 53+j85 ohms 3.05+j5.08 ohms 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 1, 2, 3 2, 3 ,5 2, 3, 4 2, 3, 4, 5 1, 2, 3 2, 3 ,5 2, 3, 4 2, 3, 4, 5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A short-shunt cumulatively-compounded dc generator builds up a voltage of 220 V at no load at rated speed. If it is operated as a differentially compounded generator, other things remaining the same, it would build up somewhat less than 220 V more than 220 V 6 V 220 V somewhat less than 220 V more than 220 V 6 V 220 V 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 During no load test, an induction motor draws power for core loss and copper loss. for copper loss and windage friction loss. for core loss and windage and friction loss. only for the small copper loss. for core loss and copper loss. for copper loss and windage friction loss. for core loss and windage and friction loss. only for the small copper loss. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines To eliminate the 5th harmonic in the induced voltages their respective pitch factor angle should be 36° 72° 18° 30° 36° 72° 18° 30° ANSWER DOWNLOAD EXAMIANS APP
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