Yeah, I saw "magneticgames" on youtube was doing something like that on youtube. Your suspicion is corect, when he has multiple ones going aroung on a circular track, they repel each other. (https://www.youtube.com/watch?v=oPzJr1jjHnQ) It's a fun toy, but it's not quite right my plan.

My issue with typical homopolar motors is that they are extreme low voltage, extreme high amperage. Most of them have ultra-small voltage drops when they run and while that's fun, they don't make good use of most power sources since amp-hours is also a bottleneck to consider when the source is chemical. So in that youtube channel, he kills his batteries in under a minute of play.

I'm thinking that I'll use a single toridal wound, air core, axially aligned coil as a stator. I'll then have my ring of magnets embedded in rotors on both side of the stator. All of both rotors magnets will point north to the stator since the wraps move towards the axle on one side and back around towards the rim on the other.

Then when I powered the toroid the rotors will spin. How fast, we'll see, but they will spin.

The calculation was done because I ordered 500 feet of 22 awg and I have neodynium magnets to use on my rotor. So I wondered what kind of force they'll experience. Obviously I won't get to make perfect use of the full 500 feet, I'll get maybe optimal use of like 240 feet of that wire, but still.