| 摘要 |
A coil (82) for generating an electromagnetic field or electrical power. The coil (82) comprises a planar insulative substrate and a flat electrically conductive track formed thereon, embodied on a circular disk printed circuit board. The board is divided into an even number of equi-angular sectors (90, 92, 94, 96, 98, 100) and the track is arranged in a radially increasing or decreasing spiral configuration upon the substrate to define a coil element in each sector. Adjacent tracks of the coil element are turned all one way or the other to terminate at an inner end (102, 104) centrally of the coil element and extend to an outer end of the coil element. The outer end of the coil element can be contiguously connected with a portion track (108) with the outer end of an opposite turned track of an adjacent coil element of the same coil (82), and the inner end (102) can be electrically connected to the corresponding inner end (110) of another track of a coil element of an adjacent coil (84), or to a power supply or load. A winding using the coil, an axial motor/generator using the winding, a rotatable mirror for dental or medical use driven by the motor/generator, components of the mirror, and a speed control for the motor/generator are also described. |
