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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