Electrical Machines With the increases in field excitation of a DC generator, its generated emf decreases. remains constant. increases. increases upto a limit and then remains almost constant. decreases. remains constant. increases. increases upto a limit and then remains almost constant. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The compensating winding in a DC machine is located in armature slots for compensation of the armature reaction. is located on pole shoes for avoiding the flashover at the commutator. is located on pole shoes to avoid the sparking at the brushes. is located on commutating poles for improving commutation. is located in armature slots for compensation of the armature reaction. is located on pole shoes for avoiding the flashover at the commutator. is located on pole shoes to avoid the sparking at the brushes. is located on commutating poles for improving commutation. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC shunt machine generates 250 V on open circuit at 1000 RPM. Armature resistance is 0.5 Ω, field resistance 250 Ω. When running as a motor takes 4 A at 250 V. Calculate the efficiency when running as a motor taking 40 A at 250 V. Armature reaction weakens the field by 4%. 82.5% 78.5% 67.5% 72.5% 82.5% 78.5% 67.5% 72.5% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In the 3-phase induction motor, the resultant flux is of a constant nature and is equal to φm, where φm is the maximum flux due to any phase 3 times maximum value of flux due to any phase 3/2 times maximum value of flux due to any phase 1/2 times maximum value of flux due to any phase equal to φm, where φm is the maximum flux due to any phase 3 times maximum value of flux due to any phase 3/2 times maximum value of flux due to any phase 1/2 times maximum value of flux due to any phase ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a DC generator if field winding attains the critical resistance the voltage generated will be zero. field winding will burn. machine will generate maximum voltage. machine will generate maximum power. the voltage generated will be zero. field winding will burn. machine will generate maximum voltage. machine will generate maximum power. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 2 pole synchronous machine is operating at 3000 rpm. Find the relation between electrical angular momentum (ωe) and mechanical angular momentum (ωm) ? ωe = ωm ωe = 2*ωm ωe = 4*ωm ωe = 1/2*ωm ωe = ωm ωe = 2*ωm ωe = 4*ωm ωe = 1/2*ωm ANSWER DOWNLOAD EXAMIANS APP
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