Energy monitoring device

• US 4,080,568 A
• Filed: 06/14/1976
• Issued: 03/21/1978
• Est. Priority Date: 06/14/1976
• Status: Expired due to Term

• Current Assignee: Roy B. Fitch Jr
• Original Assignee: Roy B. Fitch Jr
• Inventors: Funk, Laurence L.
• Primary Examiner(s): Krawczewicz, Stanley T.
• Application Number:
  US05/696,130
• Time in Patent Office: 645 Days
• Field of Search: 324/142, 235/151.21, 235/151.31
• US Class Current: 324/142
• CPC Class Codes: G01R 21/1331 Measuring real or reactive component, measuring apparent energy
• CPC Class Codes: G06Q 50/06 Energy or water supply

Abstract

The monitoring of energy consumed in a single phase, three wire electrical system is accomplished by generating a voltage proportional to the current flowing in the system, which is conveyed to a linear voltage controlled oscillator by a single electrical conductor. A waveform derived by a counter from timing pulses provided by an electronic clock circuit gates the output of the VCO to a counter, and also provides for alternation of a display between a representation of energy consumed and time of day. Selective adjustment of the voltage to frequency converting circuit'"'"'s gain provides an output indication in appropriate electrical or monetary units. All gating and resetting of counters, display multiplexing and timekeeping functions are provided by the electronic clock circuit.

Claims

1. A meter for determining and displaying the electrical rate of energy consumption of an electrical system comprising:

means for measuring the current flowing in said system and producing a voltage signal having an amplitude which varies as a function of current flow;

means for amplifying said voltage signal including manually operable means for varying the gain of said amplifying means so as to display said rate in desired units;

means for converting the output of said amplifying means into a pulse train;

first counter means for counting the pulses in said pulse train;

clock means for producing a train of clock pulses;

second counter means for counting said clock pulses and producing a display signal upon a predetermined count;

means for connecting said second counter means to said first counter means to freeze the count within said first counter means upon production of said display signal;

display means for providing a digital display; and

means for causing said display to display a number corresponding to the count frozen in said first counter means upon production of said display signal.

2. A meter as in claim 1, wherein said measuring means includes first and second transformers each having a primary winding serially connected to one wire of a three-wire system and a secondary winding serially connected to the other secondary winding and to said amplifying means.

3. A meter as in claim 1, wherein said amplifying means includes an operational amplifier, said varying means includes a variable resistor connected in feedback to said operational amplifier and said converting means includes a diode connected to the output of said operational amplifier for producing a rectified signal, a capacitor connected to said diode for storing the peak valve of said rectified signal and a means for producing a pulse train having a frequency which varies as a function of the value stored on said capacitor.

4. A meter as in claim 1, wherein said display includes a digital display for displaying the cost per unit of time of electricity being currently consumed.

5. A meter as in claim 1, wherein said causing means includes logic means connected between said clock means and said display means and between said first counter means and said display means for alternately connecting said clock means to said display for displaying the time and said first counter means to said display means for displaying the rate of energy consumption.