Revenue meter with integral current transformer

• US 6,064,192 A
• Filed: 04/08/1998
• Issued: 05/16/2000
• Est. Priority Date: 04/08/1998
• Status: Expired due to Fees

• Current Assignee: Ohio Semitronics, Inc.
• Original Assignee: Ohio Semitronics, Inc.
• Inventors: Redmyer, John D.
• Primary Examiner(s): BROWN, GLENN WARNER
• Application Number:
  US09/056,959
• Time in Patent Office: 769 Days
• Field of Search: 324/126, 324/127, 324/114, 324/117 R, 324/117 H
• US Class Current: 324/127
• CPC Class Codes: G01R 1/22 Tong testers acting as secondary windings of current transformers
• CPC Class Codes: G01R 15/186 using current transformers with a core consisting of two or more parts, e.g. clamp-on type G01R15/142 - G01R15/16 take precedence; tong testers G01R1/22
• CPC Class Codes: G01R 21/1331 Measuring real or reactive component, measuring apparent energy
• CPC Class Codes: G01R 22/00 Arrangements for measuring time integral of electric power or current, e.g. electricity meters
• CPC Class Codes: H01F 38/30 Constructions

Abstract

An integral meter and current transformer to measure single phase active and reactive energy, voltage and frequency in industrial, commercial and multi-family residential applications. The meter CT is the primary sensing element in a revenue metering system encompassing multiple meter CTs serially connected in groups in communication with data cores for collection and reporting of energy consumption. Numerous data cores may be networked to report to a central station which may be remotely interrogated over the network or dial up modem connection. The meter CT utilizes a split-core transformer with substantially overlapping fingers. Disengaging split-core sections of the meter CT enables it to be easily installed around a loaded conductor without the interruption of power to the load.

Claims

1. An electric meter configured to compute an amount of energy consumed by a load powered by a mains voltage, comprising:

a separable housing;

a split-core current transformer located within said housing that is configured to inductively sense an amount of current flowing through a conductor coupled to said load, said transformer comprising a metallic core that includes;

first and second spaced sections, oppositely disposed, each of said first and second sections being surrounded by wound coils; and

a removable portion comprising third and fourth elongated sections that are configured to form an opposite side of said metallic core, and that are substantially a same length as said first and second sections;

said first and second sections being configured to receive and slideably engage with said third and fourth elongated sections to form a rectangular core having a central opening;

said conductor being located within said central opening such that said wound coils are configured to generate a coil output signal proportional to the amount of current flowing through said conductor; and

processing circuitry that is configured to be responsive to said coil output signal from said wound coils and said mains voltage such that said processing circuitry computes the amount of energy being consumed by the load coupled to said conductor and to generate an electrical output signal corresponding to the amount of energy being consumed by said load.

2. The meter of claim 1 wherein said electrical output signal includes a series of pulses having a frequency that is proportional to said amount of energy being consumed.

3. The meter of claim 1 wherein said computed amount of energy being consumed is expressed in watt-hours.

4. The meter of claim 1 wherein said computed amount of energy being consumed is expressed in var-hours.

5. The meter of claim 1 wherein said electrical output signal from said processing circuitry also includes a frequency of said mains voltage.

6. The meter of claim 1 wherein the processing circuitry is located within said housing.

7. The meter of claim 1 further comprising communication circuitry configured to transmit said electrical output signal from said processing circuitry to a central data collector.

8. The meter of claim 7 wherein said communication circuitry comprises a serial data interface.

9. The meter of claim further comprising signal treatment circuitry operatively positioned to receive said coil output signal.

10. The meter of claim 9, wherein said signal treatment circuitry electrically isolates said mains voltage from said processing circuitry.

11. The meter of claim 10 further comprising an opto-coupler that is configured to perform said isolation.