Electronic watt-hour meter
US4359684A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 12, 1978 |
| Grant date | Nov 16, 1982 |
| Priority date | — |
| Expiry date | May 12, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R21/127
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An electronic watthour meter for connection in a two-wire power distribution circuit comprises a shunt connected in one of the wires and an electronic circuit comprising a transconductance multiplier, a V to F converter and a reversible counter. The DC power supply of the electronic circuit is referred to the wire containing the shunt, which wire is always live, so that the electronic circuit "floats" electrically on this live wire. The first input of the multiplier can therefore be directly connected across the shunt, and the second input is connected via a high value resistance to the other wire so as to receive an input current representative of the voltage between the wires. To eliminate the effects of drift in the multiplier, the polarity of the input current to the multiplier and the direction of counting of the counter are periodically and simultaneously reversed by a square wave signal of 1:1 mark space ratio. The electronic circuit is implemented using LSI techniques.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.