Induction Motor Theory

Jerry Bednarczyk, P.E.

Course Outline

This course will present a review of the development of the equivalent motor circuit and the various formulas that the engineer can use to determine the induction motor characteristics to best suit the application. The course will require approximately 3 hours of study time to review and comprehend the contents. A calculator is required with trigonometric functions.

This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of the course materials.

Learning Objective

At the conclusion of this course, the student will:

• Have a basic understanding of induction motors;
• Able to develop an induction motor equivalent circuit;
• Understand the basic formulas to determine motor characteristics;
• Be able to determine how varying a particular motor characteristic will impact other characteristics; and
• Determine the following characteristics of an induction motor:
• Synchronous speed
• Rotor speed / motor slip
• Total motor power input
• Motor power output
• Motor efficiency
• Torque developed by the motor
• Total impedance of a motor

Intended Audience

The course is recommended primarily for Electrical Engineers or others desiring a basic understanding of the characteristics of an AC induction motor.

Course Introduction

The characteristics of an induction motor are best determined by a series of tests, generally under load. However, for large motors, this is not always practical. The motor characteristics can be approximated by calculations using an equivalent circuit for the motor and using a series of formulas.

Course Content

The course content is in a PDF file Induction Motor Theory. You need to open or download this document to study this course.

Course Summary

These formulas, while presenting idealized conditions in a relatively simplified manner, provide the engineer a basic understanding of the variables to be considered in the design of motors. Factors such as motor starting factors (i.e; high inrush currents), varying speeds and other items all would need to be considered in the total design.

For additional information related to this subject, please visit the following websites or webpages:

Wikipedia - http://www.en.wikipedia.com

Electric Motors Reference Center - http://www.electricmotors.machinedesign.com

LM Photonics - http://www.lmphotonics.com

Quiz

Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.

DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDHonline.com or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered professional engineer. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.