| 摘要 |
PURPOSE:To enable to accurately control a speed irrespective of the rotating speed by altering the conversion ratio of an electric amount proportional to the rotating speed in response to the rotating speed. CONSTITUTION:Two speed controllers 4, 13 are provided, and normal-closing contacts 16, 18, 19, 21 are closed and normal-open contacts 17, 20 are opened to control by a speed controller 13 at a low speed time. The previous contacts are changed to control by the controller 4 at a high speed time. In this speed controller, the conversion ratio (1/10, 10/1 times) of a converter 3a is varied in response to the rotating speed of a motor 1, thereby using differently a measuring range according to high or low speed operation. Accordingly, a suitable reference voltage can be always applied to the controller 4 and the current controller 5 of 13-th stage. |
