I, absolutely, do not question your information here or knowledge of this (this is beyond my knowledge). I am just curious if this is based only on mathematical models, or was this or can this be confirmed by measuring the harmonics with sensor based equipment? I’m just asking, because i have no idea; and i would love to know how they could actually measure this. What kind of sensors, and where are they placed? Very interesting info. Thx for that. [/quote]

Yes thats pretty easy to measure.. just use a variable strobe light and match the speed.. that will tell
you what the RPM is.. I did a lot of this stuff back at work