We have a VFD on a 200 HP pump at work(petroleum plant). It replaced a huge worthington diesel engine and was designed to be variable speed. It can run anywhere from wide open to just barely turning.
Old engine looked very similar to this one but was on a concrete pad. Last time we had it rebuilt there was only a couple guys in the country who specialized in them. The dude looked to be about 80 but damn if he didnt get it done.
