1. By controlling the ohms supplied to the motor windings, a wide range of motor speeds can be obtained.
a. True
b. False
2. The essential features and parts of DC motors and generators are the same.
a. True
b. False
3. The direction of armature rotation of a DC motor depends on the direction of the current in the field and armature
circuits.
a. True
b. False
4. Normal or base speed for a DC motor is obtained by connecting full voltage to both the armature and shunt field.
a. True
b. False
5. Three factors limit the current taken by the armature from a DC source.
a. True
b. False
Name: Class: Date:
Unit 43 About DC Motors
6. The armature or rotating member of a DC motor is a cylindrical ____ assembly mounted directly on the motor shaft.
a. iron b. carbon
c. graphite d. steel
7. Three types of DC industrial motors are widely used: series, shunt, and ____.
a. low-voltage b. control
c. compound d. synchronous
8. The direction of rotation of a DC motor is determined by facing the commutator end of the motor, which is generally
the ____ of the motor.
a. front b. rear
c. top d. bottom
9. Most DC speed controllers use solid-state devices such as ____ to provide speed control for the motor.
a. diodes b. GLOs
c. gates d. SCRs
10. The armature current must be limited by an external resistor or a ____ rheostat.
a. liquid b. constant
c. disc d. starting
Name: Class: Date:
Unit 43 About DC Motors