AC GENERATION ANALYSIS
Basic AC Theory
The frequency of a 120 V AC circuit is 60 Hz. Find the following:
Angle from reference at 1 msec
Induced EMF at that point
w = 2 p f
= 2 (3.14) (60 Hz)
= 376.8 radians/sec
= (376.8 radian/sec) (.001 sec)
= 0.3768 radians
= Emax sin q
= (120 V) (sin 0.3768 radians)
= (120 V) (0.3679)
= 44.15 V
AC generation analysis is summarized below.
Voltage, Current, and Frequency Summary
The following terms relate to the AC cycle: radians/second, the velocity the loop
turns; hertz, the number of cycles in one second; period, the time to complete
Effective value of AC equals effective value of DC.
Root mean square (RMS) values equate AC to DC equivalents:
= 0.707 Imax
= Effective Current
- E = 0.707 Emax
= Effective Voltage
= 0.636 Imax
= 0.9 I = Average Current
- Eav = 0.636 Emax
= 0.9 E = Average Voltage
Phase angle is used to compare two wave forms. It references the start, or zero
point, of each wave. It compares differences by degrees of rotation. Wave
forms with the same start point are "in-phase" while wave forms "out-of-phase"
either lead or lag.