Electrical Machine Design Objective Questions with Answers - ObjectiveBooks

Electrical Machine Design Objective Questions with Answers

Practice Test: Question Set - 10


1. By which of the following methods motor rating for variable load drives can be determined?
    (A) Method of average losses
    (B) Equivalent current method
    (C) Equivalent torque method
    (D) All of the above

2. ________ are used for construction of core of electromagnets.
    (A) Soft magnetic materials
    (B) Hard magnetic materials
    (C) Either (A) or (B)
    (D) None of the above

3. _________ are always double layer type.
    (A) Closed windings
    (B) Open windings
    (C) Either of the above
    (D) None of the above

4. Power transformers should be designed to have maximum efficiency
    (A) At one-fourth load
    (B) At one-half load
    (C) At or near full load
    (D) Any of the above

5. ________ is the common method of applying brushes to the commutator.
    (A) Radial
    (B) Trailing
    (C) Reaction
    (D) All of the above

6. The cold rolled grain oriented steel has _________ permeability in the direction of the grain orientation.
    (A) Minimum
    (B) Maximum
    (C) Nil
    (D) None of the above

7. The voltage control in electric supply networks in required on account of which of the following reasons?
    (A) Adjustment of voltage at consumers premises within statutory limits
    (B) Control of active and reactive power
    (C) Adjustment of short period daily and seasonal voltage variations in accordance with variations of load
    (D) All of the above

8. For large power transformers, self oil cooled type or air blast type which of the following values of current density may be used?
    (A) 1.0 to 1.2 A/mm2
    (B) 1.5 to 2.0 A/mm2
    (C) 2.2 to 3.2 A/mm2
    (D) 3.2 to 4.2 A/mm2

9. Which of the following in an application of D.C. motors?
    (A) Traction
    (B) Drives for process industry
    (C) Battery driven vehicles
    (D) All of the above

10. _________ brushes are fragile and cause excessive wear of commutator,
    (A) Natural graphite
    (B) Hard carbon
    (C) Electro graphitic
    (D) Metal graphite

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