avr is automatic voltage regulator for power generators
If you mean the build-in pcb of a fuel/diesel generator which build-up voltage initially and then keep it stable under any load, then read this: First you need to see your generator minimum requirements to determine specs of AVR. You will probably found a label on generator with those Information: Ex. volt (maximum excitation voltage) Ex. amp (maximum excitation amperage) Your AVR output must exceed those specs. If generator is brushless type in most cases it does. Also input voltage of AVR must be the same as output of generator (ex. 110V110V, 220V220V). If generator is triple phase then you can do the same (ex. 380V380V, 440V440V) but if generator have output in star formation then you can use node for a smaller voltage of AVR (ex. 380V220V, 440V253V). If generator work in parallel operation (usually marine main generators does) then things get complicated. In this case AVR is good to support current transformer to make generator more elastic under load fluctuations and match other generators in the same circuit.
