How fast do the beaters on a vacuum cleaner spin?

It’s actually variable. While most AC electric motors in the US spin at either 1700–1800 or 3500–3600 RPM because of our 60Hz electrical system, those beaters are not driven directly; there is a drivetrain involved that gears it down, and what the exact gear ratio is is not the same in every vacuum.

If I had to guess though, based on how fast I can wrap an unseen cat toy around the roller on mine, I’d say 600 RPM (10 revs a second) tops, at least on mine.

How can I convert that to MPH? Or at least a guesstamate.

Approx 60mph.

I used to have this formula in my HP48G…. lets reverse-engineer it…

(diam_in_inches * 3.1415) = inches per revolution…
divided by 12 = feet per revolution…
times RPM to get feet per minute…
times 60 to get feet per hour…
then divided by 5,280 to get MPH….
( (3.1415 / 12) * 60 ) / 5280 = 0.029749….
so…..

diam-in-inches * RPM * 0.0029749 = MPH

Size matters though. Given the small diameter, that beater really isn’t going as fast as you’d think. Assuming a 2” diameter, we’re looking at only 4 MPH; to get 60 MPH would require a speed of just over 10,000 RPM. On the other hand, an average-sized car tire (about 23” diameter) rolling at 60MPH is only turning about 877 RPM.

Or just use this with both gear ratios set to 1.00 and asking to solve for Vehicle Speed.

Haha, that’s all very, err…interesting @jerv, but the fact of the matter is that I guessed…wildly :D

I guessed wildly too, with a bat from hell flying at my face!

Now you know why the rest of the Navy looked at us Nukes funny; we do stuff like that for fun.