DC Generator MCQ

91. Lap winding is preferred for which type of machines?

1. Low current and low voltage
   
2. High current and high voltage
   
3. High current and low voltage
   
4. None of the above

92. For a full pitch winding, the generated voltages in both coil slides

1. are exactly in phase
   
2. in quadrature
   
3. exactly 180° out of phase
   
4. approximately 180° out of phase

93. Use of fractional pitch winding

1. Make it stiffer
   
2. Results in the reduced leakage reactance
   
3. Results in reduced axial length of the machine
   
4. All of the above

94. The variable loss in a dc shunt machine is

1. Iron loss
   
2. Shut field loss
   
3. Armature copper loss
   
4. Friction and windage loss

95. Reluctance torque in rotating machines is

1. Air gap is not uniform
   
2. Reluctance seen by stator mmf varies
   
3. Reluctance seen by rotor mmf varies
   
4. Reluctance seen by the working mmf varies

96. Which of the following quantity maintains the same direction whether a D.C. machine runs as a generator or as a motor?

1. Induced e.m.f.
   
2. Armature current
   
3. Field current
   
4. Supply current

97. The machine which works on dynamically induced emf is

1. DC motor
2. DC generator
3. Transformer
4. Induction Motor

98. In a DC generator current to external circuit from armature is given through

1. slip rings and brushes
2. commutator and brushes
3. solid connections
4. starter circuit

99. The length of the air gap under the poles of a DC machine is not kept uniform so as to

1. obtain a suitable main field flux
2. obtain better cooling
3. obtain sinusoidal armature mmf wave
4. minimize the effect of armature mmf on main field

100. As we go from generator end towards load, the severity of a particular fault

1. decreases
2. does not depend on location
3. remains same
4. increases