Electrical Machines
Consider the following statements regarding the speed control of dc motors : 1. ward-leonard method is suitable forconstant-torque drives 2. Ward-leonard method is suitable for constant-power drives 3. field-control method facilitates speed control below base speed 4. Armature-resistance control method is more efficient than ward-leanard method 5. Field-control method is suitable for constant-torque drives 6. Armature-resistance control method is suitable for constant-torque drives From these, the correct answer is

 1, 3, 5
 1, 2, 5
 1, 2, 6
 1, 4, 6

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Electrical Machines
The compensating winding in a DC machine

 is located on commutating poles for improving commutation.
  is located on pole shoes to avoid the sparking at the brushes.
  is located on pole shoes for avoiding the flashover at the commutator.
 is located in armature slots for compensation of the armature reaction.

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