Systems and methods for reducing attenuation in current transducers

Patent metadata

Field	Value
Publication number	US-9448261-B2
Application number	US-201414251432-A
Country	US
Kind code	B2
Filing date	Apr 11, 2014
Priority date	Apr 11, 2014
Publication date	Sep 20, 2016
Grant date	Sep 20, 2016

Abstract

A device includes a first axial ring, a first radial ring disposed below the first axial ring and a second radial ring disposed below the first axial ring. The first radial ring and the second radial ring are spaced apart in a radial direction. The device also includes an electrically non-conductive isolating ring disposed between the first axial ring and the first radial ring and a current sensor disposed between the first radial ring and the second radial ring. Further, the device includes a second axial ring disposed below the first radial ring, the second radial ring, and the current sensor. The first axial ring, the first radial ring, the second radial ring, and the second axial ring form a magnetic shield and an electrically conductive shell around the current sensor. The isolating ring disrupts the electrical continuity of the electrically conductive shell.

First claim

The invention claimed is:

1. A device, comprising:
a first axial ring;
a first radial ring disposed below the first axial ring in an axial direction;
a second radial ring disposed below the first axial ring in the axial direction, wherein the first radial ring and the second radial ring are spaced apart in a radial direction perpendicular to the axial direction;
an electrically non-conductive isolating ring disposed between the first axial ring and the first radial ring;
a current sensor disposed between the first radial ring and the second radial ring; and
a second axial ring disposed below the first radial ring, the second radial ring, and the current sensor;
wherein the first axial ring, the first radial ring, the second radial ring, and the second axial ring form a magnetic shield and
wherein the isolating ring disrupts electrical continuity of the first axial ring, the first radial ring, the second radial ring, and the second axial ring.

2. The device of claim 1 , wherein the first radial ring has a first perimeter, the isolating ring has a second perimeter, and the first perimeter is equal to the second perimeter.

3. The device of claim 1 , wherein a second isolating ring is disposed between the first axial ring and the second radial ring.

4. The device of claim 1 , wherein the isolating ring comprises a one-piece structure spanning the first radial ring and the second radial ring.

5. The device of claim 1 , comprising a potting material disposed between the first axial ring and the second radial ring.

6. The device of claim 1 , comprising a plurality of current sensors.

7. The device of claim 1 , comprising a second isolating ring disposed between the second axial ring and at least one of the first radial ring or the second radial ring.

8. The device of claim 1 , wherein the isolating ring has a thickness between 1 micrometer and 20 millimeters.

9. The device of claim 1 , wherein the isolating ring is disposed over a portion of the first radial ring.

10. A method of assembly, comprising:
disposing a first radial ring adjacent to a first surface of a current sensor;
disposing a second radial ring adjacent to a second surface of the current sensor, wherein the first surface and the second surface are on opposite sides of the current sensor, wherein the first radial ring and the second radial ring are spaced apart in a radial direction perpendicular to an axial direction;
disposing an isolating ring on top of the first radial ring in the axial direction;
disposing a first axial ring on top of the first radial ring, the current sensor, and the isolating ring in the axial direction; and
disposing a second axial ring below the first radial ring, the current sensor, and the second radial ring in the axial direction.

11. The method of assembly of claim 10 , wherein comprising disposing the isolating ring on top of the second radial ring.

12. The method of assembly of claim 10 , wherein comprising disposing a potting material on top of the second radial ring.

13. The method of assembly of claim 10 , comprising disposing a second isolating ring below at least one of the first radial ring or the second radial ring and above the second axial ring.

14. A system, comprising:
a device comprising:
a housing;
a first axial ring disposed in the housing;
a first radial ring disposed on top of the first axial ring in an axial direction;
a second radial ring disposed on top of the first axial ring in the axial direction, wherein the first radial ring and the second radial ring are spaced apart in a radial direction perpendicular to the axial direction;
a current sensor disposed in between the first radial ring and the second radial ring;
an isolating ring disposed on top of the first radial ring;
a second axial ring disposed on top of the first radial ring, the current sensor, and the isolating ring;
a lid disposed above the second axial ring and coupled to the housing to form a non-conductive shell; and
a plurality of connector pins electrically coupled to the current sensor and disposed in the housing;
wherein the first axial ring, the first radial ring, the second radial ring, and the second axial ring form a magnetic shield and
wherein the isolating ring disrupts electrical continuity of the first axial ring, the first radial ring, the second radial ring, and the second axial ring.

15. The system of claim 14 , wherein the isolating ring and the second axial ring have substantially the same shape.

16. The system of claim 14 , wherein the isolating ring has a first perimeter, the first radial ring has a second perimeter, and the first perimeter is equal to the second perimeter.

17. The system of claim 14 , comprising calibration circuitry electrically coupled to the plurality of connector pins and configured to calibrate the measurement output of the current sensor.

18. The system of claim 17 , comprising protection circuitry electrically coupled to at least one of the calibration circuitry or the plurality of connector pins and configured to protect at least one of the calibration circuitry or the current sensor from harmful signals.

19. The system of claim 14 , wherein at least one of the first radial ring or the second radial ring comprises a tape-wound shield.

20. The system of claim 14 , wherein the current sensor comprises a sensor core and a coil disposed around the entirety of the sensor core.

Assignees

• Gen Electric

Inventors

• Weller Nathan Andrew

Classifications

• G01R15/186

  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 title

• G01R19/0092 Primary

  Measuring current only · CPC title

• G01R35/02 Primary

  of auxiliary devices, e.g. of instrument transformers according to prescribed transformation ratio, phase angle, or wattage rating · CPC title

• G01R35/005

  Calibrating; Standards or reference devices, e.g. voltage or resistance standards, "golden" references (G01R33/0035, G01R35/002 take precedence) · CPC title

• G01R15/183

  using transformers with a magnetic core · CPC title