De truc staat uitgelegd in een van de comments op de Facebook-pagina:
The oscillations of the magnets at the beginning prove that there is initially a magnetic field. No magnetic field, no oscillations. This is not the one of the magnets (that turns with the magnet). This is not a parasitic magnetic field, considering the oscillation speed (hence the strength of the magnetic field). Moreover, the equilibrium position of the magnet is – would you believe! – aligned with the coils.
This magnetic field is thus produced by the coils. Coils do not create a magnetic field without electrical current. (Without such a current, they are just a stack of copper.) This prove that there is yet an electrical current before the generator is “started”.
About the LEDs lighting: They are put in parallel with the coils. In a constant magnetic field and for a constant current, coils act like wires: the LEDs are short-cut. However, when moving, the magnetic field of the magnets impact the impedance of the coils. At some points, they no longer short-cut the LEDs, allowing the latter to get some current