Based on the published photos of Orbo (Steorn's perpetual motion device that didn't work when it was demonstrated for the first time in public on July, 2007), a fellow named Axle has drawn an exploded view of the gizmo.
The "stator" is shown in green and blue, and contains a circular arrangement of eight magnets fit into slots around the periphery of a central cavity. In that cavity spins the "rotor", with four magnets around its circumference. The stator and rotor are connected by two bearings, seen in orange — the weak links that, according to Sean, put an end to the demo.
Some of this detail is conjecture, given the quality of the photos that the design is drawn from. The design resembles a variation of a classic magnet motor, a recurring motif among attempts to create perpetual motion machines. A magnet motor cannot generate more energy than is put into it because, due to the way magnetic fields work, there will either be a stable state where the rotor is being pushed in one direction just as strongly as it is being pushed in the other direction, or else the operation of the motor will progressively weaken the magnets themselves until the spinning stops. If Orbo does work, then it's doing something very unusual with the configuration of magnets, perhaps (according to Sean) somehow taking advantage of the time variance involved in the effect of magnetic viscosity.
I'm beginning to think that Steorn is a game publisher, or some other kind of company that is doing all this as a publicity stunt.
Previously on Boing Boing:
• Video of Steorn CEO explaining why its perpetual motion device failed at demo
• Huffington Post on Steorn's "free energy"
• Steorn's "free energy machine" to be unveiled today
• More on "free energy" company
• Company claims to have generator with more than 100% efficiency