How do centrifuges work?
I’m not asking like “how do they make the solids settle out at the end?”, I get that, that’s intuitive and easy, everyone understands that. You spin something long enough, the centrifugal force* will settle things out.
*and yes, I know the difference between centrifugal and centripetal force and that centrifugl force isn’t “real”
What I’m asking is, how does the MACHINE work? Specifically for the lab-type centrifuges that can spin up to 20,000 rpm and higher. Surely it isn’t a mechanical drive with a gear up ratio. But going up to 20,000 rpms needs some special mechanism, both for the forces, and to go faster in the first place since electric motors are limited by the frequency of the AC current (60hz = 3600 rpm max, since that’s as fast as the poles will change, no?)
I was looking stuff up and found centrifuges with hydraulic drives, but those were industrial centrifuges handling lots of material.
Ultimately, I need to make/have made centrifuges that can spin 20,000 rpm +, handling liquid, but not tiny lab amounts, larger amounts, like 3-8 gallons.
Not that I’m an engineer, and not that it needs inventing since this stuff already exists, but if I were designing it, I would guess the best way would to increase the frequency of the current and create a few more phases with a special transformer set up (tesla coil? but I don’t even know how a tesla coil even works I only know what it does) so that an electric motor could just by itself eventually spin up to 20,000 rpm. Or I’d “gear up” with “gears” made of magnets on the rims instead of teeth, so they never actually touch. Obviously they’d have to be highly exactly machined, as would any design realy I guess, dealing with those speed.
So how do these ubiquitous lab tools usually work?