Electrical Machine Design(Electrical Engineering ) Questions and Answers

Question 1. In a D.C. machine, the value of peripheral speed should not, normally, exceed
  1.    10 m/s
  2.    20 m/s
  3.    30 m/s
  4.    40 m/s
Explanation:-
Answer: Option C. -> 30 m/s
Question 2. Volt box is a component to
  1.    extend voltage range
  2.    measure voltage
  3.    compare voltage in a box
  4.    none of the above
Explanation:-
Answer: Option A. -> extend voltage range
Question 3. A moving-coil permanent-magnet instrument can be used as _____ by using a low resistance shunt.
  1.    ammeter
  2.    voltmeter
  3.    flux-meter
  4.    ballistic galvanometer
Explanation:-
Answer: Option A. -> ammeter
Question 4. In an AC co-ordinate potentiometer, the currents in the phase and quadrature potentiometer are adjusted to be
  1.    out of phase by 90°
  2.    out of phase by 60°
  3.    out of phase by 30°
  4.    out of phase by 0°
Explanation:-
Answer: Option A. -> out of phase by 90°
Question 5. For measuring current at high frequency we should use
  1.    moving iron instrument
  2.    electrostatic instrument
  3.    thermocouple instrument
  4.    none of the above
Explanation:-
Answer: Option C. -> thermocouple instrument
Question 6. D.C. machines designed with a large value of air gap length have
  1.    worst, ventilation
  2.    poor ventilation
  3.    better ventilation
  4.    none of the above
Explanation:-
Answer: Option C. -> better ventilation
Question 7. In direct cooled system using hydrogen both stator and rotor conductors are made
  1.    solid
  2.    hollow
  3.    perforated
  4.    any ofthe above
Explanation:-
Answer: Option B. -> hollow
Question 8. On which of the following variables heat convected depends ?
  1.    Power density
  2.    Temperature difference between heated surface and coolant
  3.    Thermal resistivity, density, specific heat
  4.    Gravitational constant
  5.    All of the above
Explanation:-
Answer: Option E. -> All of the above
Question 9. By which of the following methods motor rating for variable load drives can be determined ?
  1.    Method of average losses
  2.    Equivalent current method
  3.    Equivalent torque method
  4.    Equivalent power method
  5.    All of the above
Explanation:-
Answer: Option E. -> All of the above
Question 10. _________ electromagnets generally function as holding magnets.
  1.    Tractive
  2.    Portative
  3.    Either of the above
  4.    None of the above
Explanation:-
Answer: Option B. -> Portative
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