My world has a form of magic that is similar to telekinesis; that is, it makes things move. I also have technology that is essentially the same as today's real world.
Thinking about it, this seems like it could be really useful for powering certain sorts of devices. There is, in fact, a certain type of electrical generator that is powered by magic. It consists of a fixed-magnet rotor surrounded by one or more pairs of coils. The rotor has no axle or bearings; it is spun and held in place solely by magic. As a result, the generator can be fully enclosed with no exposed moving parts; is is very nearly "solid state". Of course, this means it necessarily produces alternating current (DC would require brushes), possibly in several phases, but solid state circuitry can easily rectify this into fairly constant DC.
(Alternatively, the generator has a mobile ring of permanent magnets which spins around a set of fixed coil-wrapped arms. I suspect this might actually work better, especially since the moving portion doesn't need an axle or bearings. The objective is to avoid brushes so as to minimize wear.)
How small can I make such a generator? Can I make it, say, the size of a 2032 watch battery? (At least, small enough to fit in a Smart Watch?) It should be able to generate at least 2 watts. Do any such devices (obviously, unlike my magic-powered generators, they would need an axle that can be externally driven) exist in real life?
Alternatively, is there some other way I can generate the required energy in the available size, using only the ability to make things move?
This isn't necessarily relevant, but... I've previously asked about this magic system here and here; those might provide some interesting details. In particular, magic is powered by the metabolism of living beings. For our purposes, what this means is that the generator has a constant supply of magic-energy as long as it is on or near a person (or, in some cases, an animal or other living source of magic). The generator isn't a "spin up once and coast" system; it is constantly being supplied with "fresh" kinetic energy via magic (when active; they can be made to have an "off" switch, and for safety and durability reasons, will halt themselves if separated from the person "feeding" the magic or if something happens that the rotor becomes stuck).
Also, and this happens to be extremely convenient, by nature of how generators work (and by how I imagine my magic working), a magneto-type generator will always provide exactly the electricity needed with fairly low waste. Specifically, magic causes the rotor to turn at a fixed speed, which translates into the amount of magic energy used to keep the generator spinning being directly correlated to the amount of electricity being consumed by whatever is connected to it. I can just spend the (very small) amount of extra magic to keep it spinning even if the connected device is off with minimal to negligible consequences. (Conceivably, there would be a delay as the flow of magic adjusts to changing power requirements, but this is what power regulation circuitry is for, and I need that anyway, at least in the form of an AC/DC rectifier.)