appreciate the info on the belt drive motors. I know it's probably ok to use a step up transformer with smaller motors and VFDs but I haven't seen any small 3 phase multi-tap transformers before. The ones I could find were in the 1K price range which is too expensive for a 1.5K piece of equipment.Multitap transformers are available to boost the 3 phase voltage. Most of the smaller SGs used 1HP motors so the required transformer would be very small. On that small a set up, it would be practical to put the transformer on the output side of the VFD, a practice not recommended in larger motors.
Belt drive SGs by B&S used specially balanced motors to minimize vibration.