… ah, you are perfectly right, actually I was asking to run a test at 100 km/h because I erroneously was assuming that he was using a real hub generator.
But reading better the pdf file at the beginning of this thread I’m discovering now that “a signal generator with an amplifier had been used instead”, regulated at 500hz/6.05V/0.445A !!!
That’s simply a nonsense, if he wants to make comparisons he must use real generators and not “signal generators” at 500 Hz !!!
Furthermore please be careful because in your calculations you considered 28 poles but in the reality you must consider them as 14 “couples of poles” since you need a couple N-S to produce an hertz and not just a single pole, so 500 Hz makes 256/288 km/h (26”/28” respectively) !!!!
To make tests in this way is a nonsense !!

Here below a picture showing frequency and voltage from a standard Shimano dynohub at 20km/h on a 28” wheel.
Do you see?? 20km/h is 20000/3600 m/s that divided by 2.150 m (28” wheel) makes 2.58 turns per second, i.e. 2.58 X 14 (couples of poles) = 36 Hz (approx)