Condition operated load control
US4172998A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 28, 1977 |
| Grant date | Oct 30, 1979 |
| Priority date | — |
| Expiry date | Oct 28, 1997 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/40
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The disclosed apparatus operates a load in one mode in response to one cyclically occurring event and in a second mode at a specified time in the cycle regardless of the phase of the one event in the cycle. According to a specific embodiment, the apparatus turns on lights at sunset and turns them off at a later nighttime hour, preferably the same hour each night. A generator stores signals in an accumulating memory at one rate during daylight hours and at a faster rate, preferably twice the daylight rate, during nighttime hours. When the memory content reaches a preset level during the night, it turns off the switch that had turned on the lights at sunset and empties itself of storage until sunrise.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.