We have Farm Fans CF 225 that the ratchet drive just does not adjust properly. You adjust the bolt some and it either doesn't change or it goes to far. Several years ago we put new one way needle bearings in, helped some but I think that clutch system is just worn out and parts are NLA. Would like to change it to some kind of VFD type system. Anyone done something like this or know what I would need to make this work? Does not need to be automated to moisture control. Just a KISS system I could manually control. This is single phase.