Remote window operating system
US4544865A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 8, 1984 |
| Grant date | Oct 1, 1985 |
| Priority date | — |
| Expiry date | Jun 8, 2004 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05B2219/45242
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A window operating system includes a motor control circuit for controlling the operation of direct current permanent magnet motors mounted on window operators associated with each window. Each of the motors on each of the windows is connected to the control circuit only by a pair of wires which both power the motor and provide information to the control circuit as to the status of motor operation. The status of motor operation is determined by monitoring the back electromagnetic force expressed by the motors. To help differentiate back electromagnetic force from supply voltage supplied to the motors, the motors are supplied with full rectified alternating current power, rather than simple direct current, so that the presence or absence of zero voltage between half waves of the voltage expressed across the motors can be monitored to determine the absence or presence of back electromotive force during those time periods.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.