Originally Posted by
instructor37
Not sure why you would take the belt off the pulley- just measure its diameter with a caliper. When you go to CONFIG- SPINDLE PULLEY you can put in your ratio there. Remember, the MAX SPEED is the spindle speed, not the motor speed, so you need to make a calculation of the spindle speed based on the motor speed X pulley ratio. Because the VFD HZ setting can be changed, you need to take that into account as well. Example- If your VFD is set to 50 Hz and the motor RPM rating is 1400 at 50HZ and your pulley ratio was 1/2, then your spindle would be turning 700 RPM at 50 Hz. Also be sure your pulley selection # is correct, as you have a lot of choices in Mach 3 designed for machines with a lot of pulley setups. Your Patriot machine has only one pulley ratio, so usually just set your ratio in PULLEY 1 and leave all the others alone. Finally, you will need to use some sort of external tachometer to verify your settings. You can generally tell if you are close just by watching the spindle, but if you want to get it near perfect the tachometer will be a must.