An electronic ampere-hour meter

Abstract

The electronic ampere-hour meter does not require any voltage supply and its operation is based on the magnetic coupling to electrical conductors feeding consumer's load. A capacitor inside the meter is charged at a rate proportional to the load current of the consumer and the number of discharges of the capacitor which occurs at a predetermined capacitor voltage is registered as the ampere-hour reading. Test results of a prototype meter for resistive, inductive and capacitive loads are compared with those from a conventional kWh meter. Results show that the Ah meter functions with reasonable accuracy and it is shown that it can be modified to work as a two-rate meter to implement a 6day-night tariff without much increase in cost, with possible application in stand-alone hydro power type schemes. Other advantages of the meter are simple construction, less wear and maintenance and lower cost compared to the conventional kWh meter.