DEVICE FOR MONITORING EXCESS CURRENT USAGE BASED ON COULOMETRIC CELL

• US 3,842,348 A
• Filed: 08/06/1973
• Issued: 10/15/1974
• Est. Priority Date: 08/06/1973
• Status: Expired due to Term

• Current Assignee: Allyn N. Goshy
• Original Assignee: Allyn N. Goshy
• Inventors: Goshy, Allyn N.
• Primary Examiner(s): Smith, Alfred E.
• Application Number:
  US05/385,888
• Time in Patent Office: 435 Days
• Field of Search: 324/13R,94,182
• US Class Current: 324/94
• CPC Class Codes: G01R 11/63 Over-consumption meters, e.g. measuring consumption while a predetermined level of power is exceeded
• CPC Class Codes: G01R 19/16571 comparing AC or DC current with one threshold, e.g. load current, over-current, surge current or fault current G01R19/16514, G01R19/16519, G01R19/16528, G01R19/16533, G01R19/1659 take precedence; measuring currents by using elements sensitive to the magnetic field generated G01R15/14; measuring earth resistance G01R27/18; testing for leakage or short circuits in electrical apparatus G01R31/52
• CPC Class Codes: H02H 3/093 with timing means in general H02H3/027; thermal delay H02H3/085; timing means for undervoltage protection H02H3/247

Abstract

Monitoring device for a power line including a voltage sensing means such as a zener diode for passing current whenever current on the power line exceeds a given threshold, thus causing an electro-plating coulometric cell to deplate to provide a measure of current usage above said threshold.

Claims

1. A device for monitoring current usage above a given threshold comprising a current transformer having a primary winding for connection to a power line to be monitored, a rectifier including a winding on the transformer, gating means connected to the output of the rectifier for passing current when the voltage at the rectifier output exceeds a predetermined level, means responsive to said passing current for indicating current usage on the power line above the threshold, and an integrating circuit between the rectifier and the gating means for providing momentary delays during which current surges in the power line may pass without causing the gating means to become conducting.

2. A device for monitoring current usage as defined in claim 1 wherein said means for indicating current usage comprises an electroplating coulometric cell.

3. A device for monitoring current usage as defined in claim 1 wherein said gating means comprises a zener diode.

4. A device for monitoring current usage as defined in claim 1 and further comprising at least one electroplating coulometric cell, each of which has initially a known plating charge and is connected singly to the rectifier to apply current to one coulometric cell at a time to deplate the cell as a measure of current usage, and said means for indicating current usage includes switching means for multiplying the current applied to each said coulometric cell whenever current is flowing through the gating means.

5. A device for monitoring current usage as defined in claim 1 wherein said means for indicating current usage includes an electroplating coulometric cell which initially has a known plating charge, normally has no current applied thereto, and is deplated whenever current passes said gating meAns.

6. A device for monitoring current usage as defined in claim 1 and further comprising means for providing a perceptible indication whenever current is passed by said gating means.

7. In a device for metering current usage on a power line comprising a current transformer having a primary winding for connection to a power line to be metered, a full-wave rectifier including a center-tap secondary winding on the transformer, at least two electroplating coulometric cells, each of which initially has a known plating charge and experiences a sharp voltage rise upon deplating, and a switching device normally connecting only a first of said coulometric cells across the rectifier thorugh a first resistance, which switching device is responsive to the sharp voltage rise in the first coulometric cell for connecting only a second of said coulometric cells across the rectifier through a second resistance and for providing a perceptible indication thereof, the improvement comprising gating means connected to the output of the rectifier for passing current when the voltage at the rectifier output exceeds a predetermined level, and an additional switching device responsive to current passing said gating means for substituting for each said resistance a resistance which is a predetermined multiple thereof to apply the inverse multiple of the current to the connected coulometric cell whenever current is passing said gating means in order to penalize or reward the consumer in accordance with said inverse multiple when current usage on the power line exceeds a threshold above which the voltage at the rectifier output exceeds said predetermined level.

8. In a device for metering current usage as defined in claim 7, the further improvement comprising said gating means comprises a programmed unijunction transistor.

9. In a device for metering current usage as defined in claim 8, the further improvement comprising said programmed unijunction transistor is controlled through a potentiometer to permit ready adjustment of said threshold of current usage on said power line.

10. In a device for metering current usage on a power line comprising a current transformer having a primary winding for connection to a power line to be metered, a full-wave rectifier including a center-tap secondary winding on the transformer, at least two electroplating coulometric cells, each of which initially has a known plating charge and experiences a sharp voltage rise upon deplating, and a switching device normally connecting only a first of said coulometric cells across the rectifier, which switching device is responsive to the sharp voltage rise in the first coulometric cell for connecting only a second of said coulometric cells across the rectifier and for providing a perceptible indication thereof, the improvement comprising gating means connecting to the output of the rectifier for passing current when the voltage at the rectifier output exceeds a predetermined level, an additional coulometric cell which initially has a known plating charge and normally has no current applied thereto, and means responsive to said passing current for deplating said additional coulometric cell whenever current passes said gating means and including means for controlling the rate of said deplating such that the additional cell would never be fully deplated before complete deplating of said first and second coulometric cells, the deplating of said additional coulometric cell providing a basis for applying a discount or surcharge to the basic rate measured by said first and second coulometric cells.

11. In a device for metering current usage as defined in claim 10, the further improvement comprising all said coulometric cells are in a detachable cartridge.

12. In a device for metering current usage as defined in claim 10, the further improvement comprising said gating means comprises a zener diode which is connected to said additional coulometric cell to deplate the cell in proportion to the flow of current through the zener diode.

13. A device for monitoring current usage above a given threshold comprising a current transformer having a primary winding for connection to a power line to be monitored, a full-wave rectifier including a center-tap secondary winding on the transformer, gating means comprising a zener diode for passing current when the voltage at the rectifier output exceeds a predetermined level, a diode permitting current to flow only in the direction from the rectifier to the zener diode, an integrating circuit between said diode and said zener diode for providing a momentary delay during which current surges in the power line may pass without causing the zener diode to become conducting, and means responsive to said passing current for indicating current usage on the power line above the threshold.