Basic Electrical Theory - Overview of AC Power, AC Generators, AC Reactive Components, and Voltage Regulators

A. Bhatia, B.E.

Course Outline

Alternating current (AC) unlike Direct current (DC) flow first in one direction then in the opposite direction. The most common AC waveform is a sine (or sinusoidal) waveform. This electrical training course provides a basic introduction to AC theory, electrical circuits, AC generator and voltage regulation. This course will be extremely helpful to individuals who are just beginning a career in electrical work, or who require a basic knowledge of electrical principals and equipment to better their primary responsibilities. This course is also a prerequisite for the all other electrical training.

This 4-hr course material is based entirely on US Department of Energy training materials DOE-HDBK-1011/3-92, Fundamentals Handbook, Electrical Science, and Volume 3 of 4. The volumes 1, 2 and 4 of the handbook have been separately listed.

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:

• Describe the construction and operation of a simple AC generator;
• Define effective value of an AC current relative to DC current;
• Describe the relationship between apparent, true, and reactive power by definition or by using a power triangle;
• Define power factor as it relates to true power and apparent power and understand the conditions of lead/lag power factor;
• Be able to calculate the true power, apparent power, reactive power and power factor for an AC circuit;
• State the indications of an unbalanced load in a three-phase power system;
• Understand the relationship between the speed of rotation, number of poles and the frequency output of an AC generator;
• Understand the losses found in an AC generator and be able to define the efficiency of an AC generator;
• Describe the conditions that must be met prior to paralleling two AC generators including consequences of not meeting these conditions;
• Describe the difference between a stationary field, rotating armature AC generator and a rotating field, stationary armature AC generator;
• Understand the voltage/current relationships and differences between a WYE-connected and DELTA connected AC circuits including advantages and disadvantages of each type; and
• State the purpose for voltage regulation equipment.

Intended Audience

This course is aimed at beginners, novice engineers, electricians, hobbyists, plant mechanics, service technicians, maintenance supervisors, plant engineers, contractors, energy auditors, layout professionals and general audience.

Course Introduction

In DC circuits, the polarity of the voltage source does not change over time. As useful and as easy to understand as DC is; it is not the only "kind" of electricity in use. Certain sources of electricity (most notably, rotary electro-mechanical generators) naturally produce voltages alternating in polarity, reversing positive and negative over time. Either as a voltage switching polarity or as a current switching direction back and forth, this "kind" of electricity is known as Alternating Current (AC).

It is true that in some cases AC holds no practical advantage over DC. In applications where electricity is used to dissipate energy in the form of heat, the polarity or direction of current is irrelevant, so long as there is enough voltage and current to the load to produce the desired heat (power dissipation). However, with AC it is possible to build electric generators, motors and power distribution systems that are far more efficient than DC, and so we find AC used predominately across the world in high power applications. To explain the details of why this is so, a bit of background knowledge about AC is necessary.

In this course, you are required to study the following DOE-HDBK-1011/3-92, Fundamentals Handbook, Electrical Science, and Volume 3 of 4.

Course Content

This course is based entirely on US Department of Energy training materials DOE-HDBK-1011/1-92, Fundamentals Handbook, Electrical Science, Volume 3 of 4.

The link to the document is Basic Electrical Theory - Overview of AC Power, AC Generators, AC Reactive Components, and Voltage Regulators.

Course Summary

Course Summary is in the following PDF file:

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 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.