Electric Machine Design Multiple Choice Questions - Set 02 - ObjectiveBooks

Electric Machine Design Multiple Choice Questions - Set 02

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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