I have seen a variety of outer space megastructures across sci-fi and the minds of most astrologists, such as **Bishop Rings**, **O'Neill Cylinders**, **Bernal Spheres**, and much more. What most of these interplanetary / interstellar giant space habitats have in common, other than their big size or massive need of resources to build, is that they need to continuously rotate to produce centrifugal or centripetal force, in order to give artificial gravity to the habitat inside.

However, even after looking into each page and also looking at artificial gravity, it is not clearly stated just what motor or method is used to produce this centrifugal / centripetal force. Assuming that we have all the resources we need, just what can help generate this artificial gravity needed for the space habitats?