Practice Test: Question Set - 08
1. Armature reaction in a generator results in
- (A) Demagnetization of leading pole tip and
magnetization of trailing pole tip
- (B) Demagnetization of trailing pole tip and
magnetization of leading pole tip
- (C) Demagnetizing the center of all poles
- (D) Magnetizing the center of all poles
2. The essential condition for parallel operation of two D.C. generators is that they have
- (A) Same kW rating
- (B) The same operation r.p.m.
- (C) The same drooping voltage characteristics
- (D) Same percentage regulation
3. The commutator segments are connected to the armature conductors by means of
- (A) Copper lugs
- (B) Resistance wires
- (C) Insulation pads
- (D) Brazing
4. Copper brushes in D.C. machine are used
- (A) Where low voltage and high currents are involved
- (B) Where high voltage and small currents are involved
- (C) In both of the above cases
- (D) In none of the above cases
5. Armature reaction of an unsaturated D.C. machine is
- (A) Cross-magnetizing
- (B) Demagnetizing
- (C) Magnetizing
- (D) None of above
6. In D.C. generators, lap winding is used for
- (A) High voltage, high current
- (B) Low voltage, high current
- (C) High voltage, low current
- (D) Low voltage, low current
7. If a D.C. generator fails to build up the probable cause could not be
- (A) Imperfect brush contact
- (B) Field resistance less than the critical resistance
- (C) No residual magnetism in the generator
- (D) Faulty shunt connections tending to reduce the residual
magnetism
8. An exciter for a turbo generator is a
- (A) Separately excited generator
- (B) Shunt generator
- (C) Series generator
- (D) Compound generator
9. The critical resistance of the D.C. generator is the resistance of
- (A) Field
- (B) Brushes
- (C) Armature
- (D) Load
10. With a D.C. generator which of the following regulation is preferred?
- (A) 100% regulation
- (B) Infinite regulation
- (C) 50% regulation
- (D) 1% regulation
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