I have a theory for perpetual energy. There's probably something wrong with it or someone else would've already thought of this, but I'm going to try anyway. Suppose you had a huge loop out in space. It is made of segments of magnetite, providing alternating magnetic poles along the surface without the use of energy. Now imagine a vehicle built to run along the inside of it (or outside will work too). It will have wheels and rocket engines for initial acceleration, but these can later be disregarded. It will have an inductor along the bottom of it to generate electricity from the alternating magnetic fields. It will also have an electromagnet to oppose the magnets beneath it, therefore keeping the vehicle just barely above its track. The method of transferring energy to external systems is irrelevant, although it could be done using electromagnetic radiation (radio waves or lasers or something).

The theory behind this lies in centripetal acceleration. Given a certain speed, necessary centripetal acceleration decreases as the size of the circle increases. Likewise, a larger circle requires less centripetal acceleration for a given speed. For a circle the size of Earth, you would have to travel about 55,000 km/h before 1 g of centripetal acceleration would be necessary. Obviously if you're passing by magnets at that speed, you should be able to build up enough energy to repel yourself at that acceleration. And there should be left over for gaining more speed and transferring to external sources. So am I missing something here or should this work?

By the way, I'm not looking for the pheasibility of the project. I know there's probably not enough magnetite on Earth to build such a loop and even if there was, we wouldn't be able to build it. I just want to know if it's theoretically possible.