donatello2468
28
This isn't physically possible
Nov 28, 2023,00:26 AM
What you're describing is a perpetual motion machine (https://en.wikipedia.org/wiki/Perpetual_motion) at the scale of a wristwatch, which isn't possible due to physics/thermodynamic laws. The closest we have in this case is as Nico pointed out, the JLC Atmos which although seems like it's running perpetually without any intervention but isn't actually since we have temperature changes i.e heat which is the energy source. I'd love to see this in a wristwatch form, but my guess is that there are physical constraints (large volume of gases, pendulum etc). Like others have said, there needs to some sort of external power source for a pure mechanical system to keep running forever.
In your specific example of a third barrel to run a rotor that will wind the watch, the amount of energy that this rotor "refills" when running will not be equal to the amount of energy released by this hypothetical third barrel to power this rotor (similar argument for any other mechanism). This is because there will be energy losses due to friction, heat etc along the way. Of course these will be small, and at first might "seem" like the watch is running perpetually, but over time (my guess is within some days), these energy losses will lead to a situation where the energy "refilled" by the rotor won't be sufficient to power it for even one rotation, and the watch will cease working.