Practice Test: Question Set - 02
1. In D.C. machines, air order to prevent excessive distortion of field form by the armature reaction, the field mmf must be made
- (A) Equal to that of armature mmf
- (B) Less in comparison with the armature mmf
- (C) Large in comparison with the armature mmf
- (D) None of the above
2. The weight of copper of both armature and field windings decreases with _________in number of poles.
- (A) Increase
- (B) Decrease
- (C) Either of the above
- (D) None of the above
3. The stator of a D.C. machine comprises of
- (A) Main poles
- (B) Interpoles
- (C) Frame
- (D) All of the above
4. A practical formula for determining the thickness of insulation between low voltage and high voltage windings is
- (A) 1 + 0.2 kV mm
- (B) 2 + 0.5 kV mm
- (C) 4 + 0.7 kV mm
- (D) 5 + 0.9 kV mm
5. D.C. windings are
- (A) Sometimes 2-layer type
- (B) Never 2-layer type
- (C) Always 2-layer type
- (D) None of the above
6. Helical windings are used in
- (A) Distribution transformers
- (B) Power transformers
- (C) Shell type transformers
- (D) None of the above
7. Dummy coil should not be used in
- (A) Small machines
- (B) Large machines
- (C) Either (A) or (B)
- (D) None of the above
8. Which of the following is the commonly used type of electromagnets?
- (A) Flat-faced armature type
- (B) Horse shoe type
- (C) Flat-faced plunger type
- (D) All of the above
9. Which of the following methods does not take into account the maximum temperature rise under variable load conditions?
- (A) Equivalent power method
- (B) Equivalent current method
- (C) Method of average losses
- (D) Equivalent torque method
10. Machines cooled by direct cooling method may be called
- (A) "Supercharged"
- (B) "Inner cooled"
- (C) "Conductor cooled"
- (D) Any of the above
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