Electrical Machines
The rotor winding for a 3-phase slip-ring induction motor having delta-connected stator must be connected in

  delta.
  star.
  delta or star according to need.
None of these

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines
The 3 - Φ induction motors are, by a very considerable margin, the most widely used AC motors as

  they are capable of operation under range of leading and lagging pf.
  they have maximum efficiency and maximum starting torque.
  these are cheaper in cost, simple and rugged in construction.
  they have very good speed regulation.

ANSWER DOWNLOAD EXAMIANS APP

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, 4, 6
 1, 2, 6

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 :

 2, 3 and 4
 1, 2 and 4
 1, 2, and 3
 1 and 3

ANSWER DOWNLOAD EXAMIANS APP
MORE MCQ ON Electrical Machines