They are actually measured in OPMs. Oscillations per minute. PC's website list it as 2,500-6,000 opm, but I don't know of a chart that shows the speed per number on the dial. Anytime someone refers to the PC, they always use the number dial for reference, not OPMs.
I was just looking at some of my detailing products earlier today and on the back of one of them it said that 1500 RPM = 5000 OPM...We allready went through this on another forum. There is not a chart for this but it might be a starting point for you...I hope this helps...
No real reason actually just curious. I have just been doing a lot of reading and watching videos on polisher techniques and that question just came in my mind.