BOOK_CONTENT
From Motors and Drives

Introduction

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.

© 2003 ISA

Products & Services
DC Motors
DC motors are most commonly used in variable speed and torque applications. They include brushless and gear motors, as well as servomotors.
AC Servomotors
AC servomotors are responsive, high-acceleration motors typically constructed as permanent magnet synchronous motors.
AC Motors
AC motors include single, multiphase, universal, induction, synchronous, and gear motors. They also include servomotors.  
Brushless Motors
Brushless motors are synchronous electric motors that have a magnetically (AC induction) or electronically (DC) controlled commutation system instead of a brush-based mechanical commutation system.

Topics of Interest

Basic Components 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...

Introduction 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...

Introduction Probably the easiest of drive technologies to understand is the direct current (DC) drive. This type of drive converts fixed-voltage and frequency alternating current (AC) to an...

Introduction Probably the easiest of drive technologies to understand is the direct current (DC) drive. This type of drive converts fixed-voltage and frequency alternating current (AC) to an...

AC Motor Types Introduction AC motors can be divided into two major categories-asynchronous and synchronous. The induction motor is probably the most common type of asynchronous motor (meaning speed...