192 Electrical Power Systems Technology
The output of a rectifier has a DC value and an AC ripple value, as
shown in Figure 7-27. To gain a relative index of the amount of AC varia-
tion, the ripple factor of a rectifier output waveform may be determined.
Ripple factor is expressed as:
Vr(rms)
r = ———
Vdc
where:
r = the ripple factor,
Vr(rms) = the rms value of the AC component, and
Vdc = the average value of the rectified DC voltage.
Another index used to express the amount of AC ripple is the per-
cent of ripple of a rectified DC voltage. Ripple percentage is expressed as:
Figure 7-26. Rotary AC-to-DC converter