Method and apparatus for tone controlled variable sensitivity time-of-day watt-hour metering
US4390839A · kind A · utility
2Cited by
8References
20Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Sep 30, 1980 |
| Grant date | Jun 28, 1983 |
| Priority date | — |
| Expiry date | Sep 30, 2000 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R21/007
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A time-of-day watt-hour meter shifts sensitivity whenever the utility transmits an audio tone over the power line to the watt-hour meter. Via an integrated circuit receiver, the tone causes a solid state switch to close, thus increasing the meter sensitivity by increasing the effective number of turns of a voltage coil across the 240 volt line. The effective sensitivity of the meter can be adjusted as desired by varying the duty cycle of the tone transmitted over the power line.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.