Protection circuit for a power window apparatus
US4900994A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 9, 1988 |
| Grant date | Feb 13, 1990 |
| Priority date | — |
| Expiry date | Jun 9, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H7/0855
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An automatic window glass elevating apparatus for moving a motor normally or reversely by drive control by a switch actuation to move a window glass in a closing or opening direction which has a resistor connected in series with the motor, first detector for detecting the locking time point of the motor from a point for crossing a first waveform signal representing a variation in a potential generated across the resistor by the driving current of the motor and a second waveform signal delayed from the first waveform signal for a first time and added with a first level thereto by obtaining the first waveform signal and the second waveform signal, and second detector for detecting a point for crossing a third waveform signal delayed for a second time from the first waveform signal and subtracted by a second level thereform and the first waveform signal by obtaining the third waveform signal to enable an automatic operation. Thus, the apparatus can operate an automatic circuit when the motor current decreases in a motor starting range.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.