I’ve seen this video where GOOGOL gear is depicted (it takes 10100 years on reaching the final gear) but how many generations will it take? The 5th gear takes about 10 hours in real time, by the time the 10th one starts spinning (you’re probably already dead).
The entire thing consists of 100 gears. However, even if you record or livestream a video of the entire thing: would you still be alive by the time the final gear starts spinning? The common life span of a human is around 72-73 median but some can reach 100+ up to 125.


A “generation” isn’t really a well-defined unit of measure. Generally, it’s thought to be about 30 years for a given group, but it can vary; I’ve seen some define it as 40 years. If you mean lifetimes, that’s going to vary by a lot of factors.
But to your second question, someone in the comments did the math, and I think it also answers your core question:
ETA: all of these calculations are based on that initial 3.5sec rotation. If you increase RPM, obviously the machine will turn faster accordingly. There’s some motors that can spin at 10k, 250k, and even 1M RPM.