Electrical Machines Armature reaction in a DC machine is in direct opposition to the main poles. makes an angle of 90° with the main pole axis. is in the same direction as the main poles. makes an angle with the main pole axis which is load dependent. is in direct opposition to the main poles. makes an angle of 90° with the main pole axis. is in the same direction as the main poles. makes an angle with the main pole axis which is load dependent. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a DC machine the armature mmf is stationary with respect to armature. stationary with respect to field poles. rotating with respect to field poles. rotating with respect to field poles as well as armature. stationary with respect to armature. stationary with respect to field poles. rotating with respect to field poles. rotating with respect to field poles as well as armature. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following factors improve commutation in a dc machine ? 1. High contact resistance of brushes 2. High inductance of the coils undergoing commutation 3. Shifting of brushes in the direction of rotation for a generator and in the opposite direction For a motor 4. Narrow width for the commutation bars Select the correct answer using the codes given below : Codes : 1, 2 and 4 1 and 3 1, 2, and 3 2, 3 and 4 1, 2 and 4 1 and 3 1, 2, and 3 2, 3 and 4 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The voltage regulation of a DC generator at full load being zero implies that the generator is cumulatively compounded. shunt connected. deferentially compounded. series connected. cumulatively compounded. shunt connected. deferentially compounded. series connected. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In DC generators, the cause of rapid brush wear may be any of above. imperfect contact. rough commutator surface. severe sparking. any of above. imperfect contact. rough commutator surface. severe sparking. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Semi closed slots or totally closed slots are used in induction motors, essentially to reduce magnetising current and improve power factor decrease starting torque improve starting torque increase pull out torque reduce magnetising current and improve power factor decrease starting torque improve starting torque increase pull out torque ANSWER DOWNLOAD EXAMIANS APP
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