Thanks for response, Keith. A bit more details. This is a test stand for 4WD vehicle transmission testing, with 4 PMSM wheel dynamometers(absorbers) and a common DC bus VFD system. We selected input drive transformer kVA rating (reduced comparing with rated for full scale system size)based on specific test vehicle prime mover (ICE) power capacity. As customer also requested to spin all 4 motors to the max speed (with no shaft load, but at the same time) we have a problem to evaluate if this transformer is still adequate to cover for 4 motors no load current. It would much easier for us to estimate that for induction motors, but we have very limited experience with PM motors. So, some advice would be helpful.