| 摘要 |
An intriguing and educational display structure (1) appears to be spinning upon itself without any apparent drive mechanism, power supply or bearing. The structure comprises two concentric hollow spheres (3, 5) spaced apart by a transparent fluid (6). The outer sphere is totally transparent, immobile and may rest on a tripod (2) or other type of support. The inner sphere may be partially transparent or translucent and carries over its surface, a design such as a map of the world (7). The inner sphere rotates within, and independently from the first outer one. The internal, that is self-contained drive mechanism is referenced to either a compass, a light angle detector, or a gravity sensor, and uses either a conventional electrical motor with its own internal field winding and communitator, or one made of a rotor comprising a cross-array of electromagnets (AC, BD) that interact with the earth magnetic field. |
