System for monitoring electrical energy consumption
US4147978A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 19, 1977 |
| Grant date | Apr 3, 1979 |
| Priority date | — |
| Expiry date | Dec 19, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R21/007
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An electronic monitoring circuit measures the amount of energy consumed by a system and displays the corresponding cost of the energy. An alarm circuit is triggered if the cost exceeds a predetermined amount over a given period of time. The monitoring circuit includes an electromagnetic coil which senses the magnitude of the input current and generates a d-c voltage having an amplitude corresponding to the current magnitude. The d-c voltage drives a voltage-controlled oscillator to generate an a-c signal having a frequency corresponding to the d-c voltage amplitude. The oscillator has been preset so that the generated a-c signal has a frequency representing a unit of cost of electrical power corresponding to the sensed current magnitude. A multivibrator generates a pulsed digital signal corresponding to the a-c signal frequency, each pulse indicating a unit of cost for the electrical power consumed. The pulses are accumulated in a series of decade counters which are connected through a decoder to a seven segment read-out unit for displaying the cumulative cost of the energy consumed. The counters are monitored by an alarm circuit which is triggered in response to the count exceedin…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.