Electrical Machines A dc shunt generator, when commissioned after a major repair of the field system, failed to build Up voltage. It was because there was a break in the armature circuit field resistance was higher than critical resistance field winding was wrongly connected field system lost residual magnetism there was a break in the armature circuit field resistance was higher than critical resistance field winding was wrongly connected field system lost residual magnetism ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider the following statements regarding the magnetization characteristics of a dc generator : 1. It represents the variation of field flux with field current. 2. Variation of open-circuit terminal voltage with field current is independent of speed 3. It is non-linear from zero to rated field current 4. It helps to determine the critical field resistance at a given speed 5. It always starts from the origin Which of these statements are correct ? 1, 2 and 5 2, 3 and 4 3 and 5 1 and 4 1, 2 and 5 2, 3 and 4 3 and 5 1 and 4 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines R1 is the resistance of the primary winding of the transformer. The turn ratio in terms of primary to secondary is K. Then the equivalent resistance of the primary referred to secondary is R1 /K R1 /K² K²R1 K×R1 R1 /K R1 /K² K²R1 K×R1 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A dc series motor driving and electric train faces a constant power load. It is running at rated speed and rated voltage. If the speed has to be brought down to 0.25 p.u. the supply voltage has to be approximately brought down to 0.125 p.u 0.75 p.u 0.25 p.u 0.5 p.u 0.125 p.u 0.75 p.u 0.25 p.u 0.5 p.u ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What is the actual arrangement of series wound generator? Armature and field both are parallel. Armature winding is in series with load. Armature and field both are in series with the load. Armature and field both are connected. Armature and field both are parallel. Armature winding is in series with load. Armature and field both are in series with the load. Armature and field both are connected. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Armature coil is short circuited by brushes when it lies along neutral axis. in none of above positions. along field axis. in any of above positions. along neutral axis. in none of above positions. along field axis. in any of above positions. ANSWER DOWNLOAD EXAMIANS APP
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