Electrical Machines A transformer has maximum efficiency at 3/4 load. The ratio of iron loss and full load copper loss is 9/16. 4/3. 3/4. 16/9. 9/16. 4/3. 3/4. 16/9. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines To have sparkless commutation, the armature reaction effect in a DC machine is neutralized by compensating winding and commutating poles. fixing the brush axis inline with the pole axis. shifting the brush axis from GNA to MNA. increasing field excitation. compensating winding and commutating poles. fixing the brush axis inline with the pole axis. shifting the brush axis from GNA to MNA. increasing field excitation. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The rotor of a three phase induction motor has an impedance of 0.4 + j4 ohm per phase at standstill the maximum torque occurs at a slip of _____________. 15 %. 25 %. 50 %. 10 %. 15 %. 25 %. 50 %. 10 %. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The leakage reactance of a 3-phase alternator is determined by performing zero power factor and slip tests. open circuit and short circuit tests. open circuit and zero power factor tests. short circuit and slip tests. zero power factor and slip tests. open circuit and short circuit tests. open circuit and zero power factor tests. short circuit and slip tests. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In induction motors, there is large decrease in maximum power factor when the dispersion coefficient is ________________. decreased. remains same. kept constant to certain value. increased. decreased. remains same. kept constant to certain value. increased. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Compensating windings are used in DC generators to provide path for the circulation of cooling air. mainly to reduce the eddy currents by providing local short circuit. None of these to neutralize the cross magnetizing effect of the armature reaction. to provide path for the circulation of cooling air. mainly to reduce the eddy currents by providing local short circuit. None of these to neutralize the cross magnetizing effect of the armature reaction. ANSWER DOWNLOAD EXAMIANS APP
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