I have a lot of experience both with VFD's and running motors over and under speed due to the electrical power supply hz. The 10hz difference on Brian's saw will not be a problem and the only noticeable change will be the blade speed. My Clearvue with the original Leeson US sourced motor has been running at 70hz for years and every Clearvue sold in Australia runs 50hz motors at 60hz or more. Our grid runs at 50hz which is a problem with dust extractors as it means a 33% or thereabouts reduction if motor speed.
Chris
Everything I like is either illegal, immoral or fattening