Electrical Machines For successful parallel operation of two single phase transformers, the most essential condition is that their polarities are properly connected turn- ratios are exactly equal KVA ratings are equal percentage impedances are equal polarities are properly connected turn- ratios are exactly equal KVA ratings are equal percentage impedances are equal ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What does the use the of height flux density value in transformer design lead to? Decrease in weight/KVA. Reduced copper loss. Increase in weight/KVA. Reduced iron loss. Decrease in weight/KVA. Reduced copper loss. Increase in weight/KVA. Reduced iron loss. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Under which of the following conditions hunting of synchronous motor is likely to occur ? 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. Over-excitation. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A dc shunt generator has full-load voltage regulation of 10% at rated speed of 1000 rpm. If it is now driven at 1250 rpm, then its voltage regulation at full load would remain unchanged be more than 10% be less than 10% be 12.5% remain unchanged be more than 10% be less than 10% be 12.5% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Addition of 0.3 % to 4.5 % silicon to iron increases the electrical resistivity of iron. reduces the saturation magnetization. increases the hysteresis loss. None of these increases the electrical resistivity of iron. reduces the saturation magnetization. increases the hysteresis loss. None of these ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider the following statements regarding dc machines : 1. possible resistance of shunt-field winding is 1 Ω 2. possible resistance of series-field winding is 1 Ω 3. electrographite brushes are used for 230 V, 10 A machines 4. Copper-graphite brushes are used for 230 V, 10 A machines 5. Possible armature-circuit resistance is 1 Ω From these, the correct statements are 2, 3 , 5 1, 4 2, 4 ,5 1, 3, 5 2, 3 , 5 1, 4 2, 4 ,5 1, 3, 5 ANSWER DOWNLOAD EXAMIANS APP
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