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Chapter 6

Alternating Current

Power Systems

Some of the basics of alternating current (AC) power systems were dis-
cussed in Chapter 2. You should already have an understanding of the ef-
fects of resistance, inductance, and capacitance in AC circuits. Therefore,
this chapter will deal primarily with the systems that are used to produce
AC electrical power.
The vast majority of the electrical power produced in the United
States is alternating current. Massive mechanical generators at power
plants throughout our country provide the necessary electrical power to
supply our homes and industries. Most generators produce three-phase
alternating current; however, single-phase generators are also used for
certain applications of a smaller nature. The operation of mechanical
generators relies upon a fundamental principle of electricity called elec-
tromagnetic induction.

IMPORTANT TERMS

Chapter 6 deals with AC power systems. After studying this chapter,
you should have an understanding of the following terms:

Electromagnetic Induction
Faraday’s Law
Left-Hand Rule of Generation
Single-Phase AC Voltage
Generator
Stator
Rotor
Field Pole
Prime Mover