I know it's not possible to build a perpetual motion machine, but I still got this concept running in my mind.
If you take a (longer)copper coil, and insert an axis through it(right-angled) with a magnet fixed on it,
it would generate electricity when you spin the axis. The axis and magnet rotate, thus alteration of the flux, thus electricity.
Of course normally there is a soft-iron core inserted in the coil to achieve better efficiency,
but it also brakes the movement. If you don't use a core and insert the axis+magnet into the coil,
you'd still generate a certain amount of electricity. The magnet is only braked by the friction of the axis and the air, but this friction is almost insignificant.
So if you use good bearings to reduce this friction to a minimum, and you take a coil with as much as possible windings,
and the strongest magnet you can find, you could in theory build a perpetuum mobile right? I'm almost sure I'm not right but I'm asking anyway. Just curious.
Any comments or responses are welcome.