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%.

 78.5%
 82.5%
 72.5%
 67.5%

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines
Skewing of the rotor in a 3 - Φ squirrel cage induction motor reduces

  noise, parasitic torque, starting torque and pull out torque.
  noise and pullout torque, but increase parasitic and starting torque.
  noise and parasitic torque, but increase starting and pull-out torque.
  noise, parasitic and starting torque, but increase pull out torque.

ANSWER DOWNLOAD EXAMIANS APP
MORE MCQ ON Electrical Machines