Quote Originally Posted by Jonathan View Post



You can press the >> key on the VFD to scroll through the readings until you find RPM if you're not sure. An easy way to remember it is that you know the spindle must do 24000rpm at 400Hz, since that's the maximum, so just work it out proportionately from that. Hence 250Hz is 250/400*24000=14400rpm and 280Hz is 16800rpm.
Thanks for that, I wasn't a million miles off with 15k as a guesstimate :D