TABLE OF CONTENTS To truly understand the operating principles of an electronic drive, it is first necessary to understand basic direct current (DC) and alternating current (AC) motor theory. As covered previously, the drive is the device that controls the motor. The drive and motor interact to provide the torque, speed, and horsepower necessary to operate the application. Slight differences occur between manufacturers when it comes to motor design, but the basic characteristics apply, no matter what motor is being controlled.
Direct current motors have been the backbone of industrial applications, ever since the Industrial Revolution. This is due to the motor's high starting torque capability and smooth speed control, and its ability to quickly accelerate to speed in the opposite direction.
Consult the Appendix when you need more information on an idea or term. You will also find helpful formulas and conversions related to both DC and AC motors.
Two basic circuits are in any DC motor: the armature (the device that rotates, sometimes referred to as a rotor) and the field (the stationary part, sometimes referred to as a stator). The two components magnetically interact with one another to produce rotation in the armature. We will take a closer look at each of the parts and how they interact.
Figure 3-1 indicates a very simplistic view of the basic parts of the DC motor.
As seen in Figure 3-1, the armature and the field...
