Alternating Current - Hingham

Alternating Current Chapter 12 Generating AC (12-1) Generating AC (12-1) Armature

Sine Wave Positive Alternation Negative

Alternation One Cycle AC Cycle - Alternation Cycle The complete revolution

of an AC generator. Alternation One cycle of a AC generator is made up of two alternations. Positive Alternation Negative Alternation

AC - Frequency Frequency The number of cycles in a second. Hertz The unit for frequency. Household Current 60Hz

60Hz 60 Cycles/second Degree of Rotation Degree of Rotation

Degree of Rotation Degree of Rotation Peak Peak to Peak

Amplitude Time Period t Peak

AC Values Amplitude The value of the wave from zero. (- +) Peak The maximum value of the amplitude. (- +) Peak to Peak The value measured

from one Peak (+) to the other Peak (-). Period The time of one complete sine wave. (seconds s) Frequency Number of cycles per second. (hertz Hz)

f= 1 t AC

Values Peak =500mV Period =50ms Peak to Peak 1000mV

= 1 20 f= Frequency = 0.05s

Hz Effective / RMS Values Effective value of AC is the amount of AC that produces the same heating effect as an equal amount

of DC. The Effective value is determined by the mathematical process call the Root Mean Square method or RMS. Vrms = 0.707 VPeak

AC Values Effective Voltage =

Vrms = 0.707 VPeak Vrms = 0.707 (500mV) Vrms = 354 V Non-Sinusoidal Wave Forms

Square Wave Square Wave Pulse Width Pulse Width = Period

Non-Sinusoidal Wave Forms Non-Sinusoidal Wave Forms

Non-Sinusoidal Wave Forms Fundamental Frequency The lowest frequency produced by any particular instrument is known

as the fundamental frequency. Harmonics Harmonics are higher frequency sine waves that are exact multiples of the fundamental frequency.

Volts Time(ms)