Monitoring circuit for a door operating D.C. electric motor
US4675586A · kind A · utility
13Cited by
10References
15Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jun 5, 1985 |
| Grant date | Jun 23, 1987 |
| Priority date | — |
| Expiry date | Jun 5, 2005 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S388/91
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A monitoring circuit for a door operating D.C. electric motor, the circuit comprises a first means for detecting a back EMF of the motor and producing a load signal indicative of the magnitude of the back EMF, a second means for detecting the time rate of change of the load signal and issuing an obstruction signal if the magnitude of the time rate of change of the load signal exceeds a predetermined value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.