| 摘要 |
<p>The invention is directed to a method of controlling the speed of an electronically controlled drill, hammer-drill or rotary hammer driven by an electrical motor wherein the rotational speed is first raised from zero to a predetermined start-drill speed and thereafter, from the start-drill speed up to the working speed. The rotational speed is held automatically at the start-drill speed for a predetermined time interval.</p><p>The apparatus of the invention for carrying out the above method is an electronic control circuit connected to the motor for adjusting the start-drill speed and the working speed. The electronic control circuit includes a control unit (30) for interrupting the ascent of the, rotational speed for a predetermined interval when the start-drill speed is reached.</p> |
