Electrical Machines The heat transfer by convection in a transformer least depends on surface area. color of the paint. air velocity. temperature difference. surface area. color of the paint. air velocity. temperature difference. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Under which of the following conditions hunting of synchronous motor is likely to occur ? Over-excitation. Periodic variation of load. Small and constant load. Over-loading for long period. Over-excitation. Periodic variation of load. Small and constant load. Over-loading for long period. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines To achieve spark less commutation brushes of DC generator are rocked ahead so as to bring them None of these just ahead of magnetic neutral axis. just behind the magnetic neutral axis. in magnetic neutral axis. None of these just ahead of magnetic neutral axis. just behind the magnetic neutral axis. in magnetic neutral axis. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If an additional resistance is connected in series with a DC series motor operating at rated speed, the speed of the motor will Remain unaltered. Oscillate around the normal speed. Increase. Reduce. Remain unaltered. Oscillate around the normal speed. Increase. Reduce. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The armature resistance of the dc motor is generally of the range 100 ohm. 0.1 ohm. 0.5 ohm. 50 ohm. 100 ohm. 0.1 ohm. 0.5 ohm. 50 ohm. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For satisfactory parallel operation of two transformers which of the following conditions is most essential, polarities of all transformers must be same. percentage impedance of all transformers must be same. voltage ratio of all transformers must be same. MVA rating of all transformer inversely proportional to impedance. polarities of all transformers must be same. percentage impedance of all transformers must be same. voltage ratio of all transformers must be same. MVA rating of all transformer inversely proportional to impedance. ANSWER DOWNLOAD EXAMIANS APP
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