Originally posted by sonhouse
If you have a dynamo, you have a spinning conductor generating a magnetic field but the energy for that comes from the angular momentum of the spinning shaft and if that energy is coupled to a load and you just spin up a shaft with no recurring energy, the shaft slows down and sto ...[text shortened]... hat is different about a single atom magnetic field and a magnetic field in a regular generator?
The magnetic field in a dynamo is, as you said, generated by the rotation (no different to an atom so far). If there were no load, no frictional losses, and no losses due to the resistance of the wires then the magnetic field would persist indefinitely. However, in a real dynamo this is not the case. In an atom there are no losses, the electron cannot lose its spin (although it can be flipped as the article states) and it cannot lose its charge. Consequently the magnetic field the electron generates persists indefinitely.