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 0.5 p.u 0.25 p.u 0.125 p.u 0.75 p.u 0.5 p.u 0.25 p.u 0.125 p.u 0.75 p.u 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 ? 2, 3 and 4 1 and 4 1, 2 and 5 3 and 5 2, 3 and 4 1 and 4 1, 2 and 5 3 and 5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 4-pole generator with 16 coil has a two layer lap winding. The pole pitch is 8. 4. 32. 16. 8. 4. 32. 16. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Dummy coils are used for reducing armature reaction. All of these mechanical balancing. increasing efficiency. reducing armature reaction. All of these mechanical balancing. increasing efficiency. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a dc generator operating on load with its brushes on the geometrical neutral axis (GNA), the magnetic neutral axis (MNA) is shifted in the direction of rotation. Now, if the brushes are given a lead of 90° (electrical), then the MNA will shift forward by 90° shift forward by more than 90° coincide with the GNA shift forward by less than 90° shift forward by 90° shift forward by more than 90° coincide with the GNA shift forward by less than 90° ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 4 pole DC shunt generator having a wave winding supplies 50 lamps, each of 60 W at 120 V. The armature and field resistance are 0.2 Ω and 60 Ω respectively. The current in each armature conductor is 11.5 A. 13.5 A. 23 A. 27 A. 11.5 A. 13.5 A. 23 A. 27 A. ANSWER DOWNLOAD EXAMIANS APP
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