DC Motor MCQ

41. For a given torque, reducing the diverter-resistance of a d.c. series motor

1. increases its speed but armature current remains the same
2. increases its speed demanding more armature current
3. decreases its speed demanding less armature current
4. decreases its speed but armature current remains the same

42. A d.c. series motor is accidentally connected to single-phase a.c. Supply. The torque produced will be

1. of zero average value
2. oscillating
3. steady and unidirectional
4. pulsating and unidirectional

43. The current drawn by a 220 V dc motor of armature resistance 0.5 Ω and back emf 200 V is

1. 44 A
2. 40 A
3. 440 A
4. 400 A