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DC Generators, Armature, Commuters and DC Motors


Quiz Questions

1._______________ completes the magnetic circuit between the poles and acts as a mechanical support for the other parts of the generator.
Field frame
Yoke
Both A&B
2. A practical DC generator uses electromagnets instead of permanent magnets.
True
False
3.The following picture represents _____________.?
PDH Course - DC Generators, Armature, Commuters and DC Motors 1

Ring type
Spiral type
Drum type
4.Which of the following figure shows where Armature is excited and field is unexcited?
PDH Course - DC Generators, Armature, Commuters and DC Motors 2
A
B
C
5._____________ are caused by the armature revolving in an alternating magnetic field.
Hysteresis losses
Eddy current losses
Copper losses
6. The armature resistance of a small, 28-volt DC motor is extremely low, about 0.1 ohm. When the armature is connected across the 28-volt source, current through the armature will apparently be__________.?
2.8 amperes
28 amperes
280 amperes
2800 amperes
7.

In the _________________, the field windings, consisting of a relatively few turns of heavy wire, are connected in series with the armature winding.

Series motor
Shunt motor
Compound motor
Ac motor
8. The tendency of a force to produce rotation is called torque. The amount of torque developed in a coil depends upon which of the following factors?
Strength of the magnetic field
Number of turns in the coil
Position of the coil in the field
All the above
9.The armature in a practical motor is placed between the poles of a permanent magnet but between those of an electromagnet, since a much stronger magnetic field can be furnished.
True
False
10.The purpose of the pigtail is to conduct the current, rather than subjecting the brush spring to currents that would alter its spring action by overheating.
True
False