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Single to Three Phase Conversion Circuit

Carlo B. DeLuca, PE (Ret.), MBA

Course Outline

The advent of three phase power distribution is presented with explanation of three phase structure and configuration. A treatise of Alternating Current terminology and analysis is made including relationships of sine waves, time, frequency and angles. An exercise is presented using standard terminology for determination of voltage amplitudes. A diagram of three phase waveforms is shown, illustrating phase lags and supporting related advantages.

Transformer and capacitor functions are briefly explained. Phasor analysis is discussed and applied to their effects on phase angle lagging and polarity. Each element is traced while summing the voltage sources on the circuit diagram. Careful attention is devoted to voltage values, phase angles and trigonometric calculations. Cautions are stressed in the requirement for experienced circuit designers to complete an effective circuit for each individual application.

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:

Intended Audience

The contents of this course are suitable for engineers with a working knowledge of AC circuitry, but does not require great strength in circuit design to undersand the theory. It provides a review of Alternating Current terminology and phasor representation for professional engineers preparing to study advanced subjects in AC circuits. It will assist power and facilities engineers to better understand the structure of three phase circuitry. The circuit can provide a solution to circuit designers with a need for improved stability for motor speed and smoother DC electricity conversion.

Benefit to Attendees

This course provides an effective vehicle to refresh the engineer with the terms and analyses of basic Alternating Current, particularly for three phase circuits. The circuit described offers a solution to the needs of designers for smoother running low power motors and improved DC power generation. However, it also offers an interesting treatise to theoretical circuit design.

Course Introduction

The prime object of this course is to discuss a theoretical circuit which will provide a three phase power source using a single phase input. In order to enable the presentation to include a broad engineering population, care is taken to include explanations of the terminology and expressions of Alternating Current theory. Additionally, an analysis of three phase circuit representation, including wye and delta configuration is defined. Thus, the course also provides an interesting review that is helpful in further AC studies.

The construction of the circuit utilizes transformer and capacitor effects in voltage conversion and phase angle alteration. Simple trigonometry is illustrated in phasor representation of Alternating Current waveforms. Circuit diagrams and graphical representations are presented to illustrate three phase power in the development of the basic circuit. Analysis of instantaneous voltage amplitudes and phase angles is afforded by using radian, frequency and time relationships in determining angles for amplitude evaluation.

Limitations of the circuit are generally confined to low power levels. While the theory of the circuit is simple, each application must be engineered in light of the single phase power input available, the nature of the loads and the power requirements.

Course Content

The course content is in a PDF file (100 KB) Single to Three Phase Conversion Circuit.

Please click on the above underlined hypertext to view, download or print the document for your study. Because of the large file size, we recommend that you first save the file to your computer by right clicking the mouse and choosing "Save Target As ...", and then open the file in Adobe Acrobat Reader. If you still experience any difficulty in downloading or opening this file, you may need to close some applications or reboot your computer to free up some memory.

Course Summary

Engineering can be viewed not as discovery of new things, but rather as using the things we know in order to solve needs. The circuitry described is an inventive exercise in applying what we know to offer a solution to a need. In the process of explanation, a basic tutorial of Alternating Current and three phase power is presented which can prove helpful in refreshing and increasing our electrical skills. While the theory of the circuit is straightforward, it requires considerable attention to effect a workable device. This course presents the discovery of a basic invention to resolve a need. However, it also encourages the stimulation to further explore the things we must know to complete an effective discovery.

Related Links and References

"Electrical Engineering Circuits" by Hugh Hildreth Skilling
John Wiley and Sons; Library of Congress Cat. No. 57-8897

"Basic Electrical Engineering" by A.E. Fitzgerald and David E. Higginbotham
McGraw-Hill Book Company; Library of Congress Cat. No. 56-10312


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

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DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center 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 architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.