Digital control system for electric motors in power tools and the like
US4307325A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 24, 1980 |
| Grant date | Dec 22, 1981 |
| Priority date | — |
| Expiry date | Mar 24, 2000 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S388/937
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A digital control system for electric motors in power tools of the portable or stationary type includes a microcomputer controlled speed regulator connected to the electric motor for maintaining a preselected speed of the motor substantially constant between no load and full load operation of the motor. The preselected speed is inputted to the microcomputer by means of a rotary switch or similar input switching arrangement. When the tool is just starting or the operator changes the speed switch, the microcomputer controls the speed of the motor to slowly approach the desired speed. The microcomputer is programmed to detect an overload condition and activate an alarm, and an impending kickback condition and stop the electric motor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.