| 摘要 |
<p>A rotary apparatus having a rotary shaft assembly (11), means for rotating said shaft assembly at a controlled speed (10), means for sensing the speed of said shaft assembly (13) and a feedback control for maintaining said shaft assembly at said controlled speed. The shaft comprises a plurality of location marks (12) directly imprinted on and located around said shaft assembly (11) at substantially uniformly spaced intervals. The feedback control is arranged to scan said marks in order to provide a continuous sensing of the rotational position of the shaft assembly. The marks (12) are present on the shaft assembly through having been applied to the shaft assembly while the shaft assembly (11) was rotated.</p> |
