It's always baffled me too, Quinn. Seems like a must have for most generators on CS's. I wish someone would come up with "add on" weight wheels. Preferably water filled!
With the inductive lag of even the small ST3 head I use, there is only so much you can do electronically in an AVR to reduce the power stroke variation. It was driving my own AC battery bank charger software nuts; there was a 1.5 amp, 10 Hz current variation at a 10 amp charge rate (into 120V nom. battery bank). This despite AVR compensation! I sure was surprised to see that since my charger has massive inductive and capacitive filtering- there is only 20mv of 60Hz ripple on it. It was being sampled (and displayed) once per second at a random point in the 10Hz cycle. You could watch the charge current value wander on the LCD display. I finally just added some analog filtering to the processed current signal, so my controller would just see the average value and would quit hunting with the variac motor drive.
