| 摘要 |
Speed regulation, either closed loop or open loop, in a hand-held electric tool such as a drill, a miller, a saw or, in particular, combination tools for home use, is carried out by use of a microcomputer. Then-present operating conditions such as the speed of the drill bit, the direction of rotation of the bit, the presently engaged gear, etc. are indicated by a display which has a plurality of fields which are selectively lit. Alternatively, the display can include a seven-segment indicator for displaying the speed. Overload indication is also furnished, as is an automatic shutoff when the motor current exceeds its nominal value. The display, overload indication and shutoff, etc. are all computer-controlled. |
