Remotely-controllable relays and filters therefor
US4232298A · kind A · utility
4Cited by
9References
21Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | May 12, 1978 |
| Grant date | Nov 4, 1980 |
| Priority date | — |
| Expiry date | May 12, 1998 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY04S40/121
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A remotely-controllable relay which is controlled by 175 Hz ripple voltage superimposed on the mains supply voltage in an electric-power distribution network contains an oscillator generating a signal at 173 Hz. This is mixed with the network voltage so that, when ripple voltage is present, a beat note at a frequency of 2 to 3 Hz is generated. This beat note is separated from the unwanted signals, such as the mains supply voltage, by a third order active low-pass filter to control operation of the relay. A similar technique provides simplified detection of output signals from correlation-type filters.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.