That's why I keep telling people (not on here cos I have only found this place a week ago) that before you can discount old tech as obsolete, the FIRST thing you gotta do is investigate iit and understand it in some depth.
my new one, the red one in the pictures, was built in 1956, that makes it bang on fifty years old.
if engine speed is correct, the governor will be in one place, so why not use that and a simple switch to make sure the genset never outputs wrong frequency AC?
yes, you can call it crude, or you can call it elegant.
what COUNTS is it is fifty years old, and still working.
nother example is the fuel tank with float + chain + bob weight fuel level indicator, fifty years old and it still works
you need a hell of a lot of bloody good reasons to change anything that has been PROVEN in fact and not theory to work for fifty years.
cheers