Split Rogowski coil current measuring device and methods

• US 7,538,541 B2
• Filed: 11/06/2006
• Issued: 05/26/2009
• Est. Priority Date: 11/06/2006
• Status: Active Grant

• Current Assignee: Eaton Intelligent Power Limited (Eaton Corporation PLC.)
• Original Assignee: Cooper Technologies Company (Eaton Corporation PLC.)
• Inventors: Kojovic, Ljubomir A.
• Primary Examiner(s): Nguyen; Ha Tran T
• Assistant Examiner(s): CAMPBELL, SHAUN M
• Application Number:
  US11/593,240
• Publication Number:
  US 20080106254A1
• Time in Patent Office: 932 Days
• Field of Search: 324/127
• US Class Current: 324/127
• CPC Class Codes: G01R 15/181 using coils without a magnetic core, e.g. Rogowski coils
• CPC Class Codes: G01R 15/247 Details of the circuitry or construction of devices covered by G01R15/241 - G01R15/246
• CPC Class Codes: H01F 38/30 Constructions
• CPC Class Codes: H01F 5/003 Printed circuit coils

Abstract

A split Rogowski coil assembly having distinct coil loops formed on printed circuit boards that are not joined to one another.

Claims

1. A Rogowski coil assembly, comprising:

a first printed circuit board assembly comprising first and second circuit boards disposed in a stacked relationship with respect to each other, the first and second circuit boards together comprising a concave shape defined by a first end and a second end of the first printed circuit board assembly, the concave shape configured to define an opening to allow for passage of a conductor between the first end and the second end of the first printed circuit board assembly, the first circuit board having a first section of coil formed thereon, the first section of coil comprising first and second ends, the second circuit board having a second section of coil formed thereon, the second section of coil comprising a third end and a fourth end, the first and third ends and the second and fourth ends of the first and second sections of coil, respectively, being connected in series with one another to form a first larger continuous coil loop generating a first voltage output when placed around a conductor; and

a second printed circuit board assembly separately provided from the first printed circuit board assembly, the second printed circuit board assembly comprising third and fourth circuit boards disposed in a stacked relationship with respect to each other, the third and fourth circuit boards together comprising a concave shape defined by a first end and a second end of the second printed circuit board assembly, the concave shape configured to define an opening to allow for passage of a conductor between the third end and the fourth end of the second printed circuit board assembly, the third circuit board having a third section of coil formed thereon, the third section of coil comprising first and second ends, the fourth circuit board having a fourth section of coil formed thereon, the fourth section of coil comprising a third end and a fourth end, the first and third ends and the second and fourth ends of the third and fourth sections of coil, respectively, being connected in series with one another to form a second larger continuous coil loop, generating a second voltage output when placed around the conductor,

wherein the first larger continuous coil loop is not electrically coupled to the second larger continuous coil loop, and

wherein a total voltage output of the coil assembly is the sum of the first voltage output and the second voltage output.

2. The Rogowski coil assembly of claim 1, wherein the first and second circuit boards comprise coil sections that are wound in the same direction on each printed circuit board.

3. The Rogowski coil assembly of claim 1, wherein the third and fourth circuit boards comprise coil sections wound in opposite directions on each printed circuit board.

4. The Rogowski coil assembly of claim 1, wherein the first voltage output and the second voltage output are connected in series with one another to provide the total voltage output of the coil.

5. The Rogowski coil assembly of claim 1, wherein the first coil loop and the second coil loop are not joined.

6. The Rogowski coil assembly of claim 1, wherein the first voltage output and the second voltage output are measured at a location other than at ends of the respective coils.

7. The Rogoswski coil assembly of claim 1, wherein the first and second printed circuit board assemblies are substantially U-shape.

8. The Rogowski coil assembly of claim 1, wherein the total voltage output of the coil assembly is integrated to determine the current flowing through the conductor.

9. The Rogowski coil assembly of claim 1, wherein the first printed circuit board assembly and the second printed circuit board assembly are configured to be installed around the conductor without disconnecting the conductor.

10. The Rogowski coil assembly of claim 1, further comprising a current calculating device that determines the current in the conductor using the total voltage output.

11. The Rogowski coil assembly of claim 10, wherein the current calculating device is a computer.

12. The Rogowski coil assembly of claim 1, further comprising a voltage measuring device coupled to the first voltage output and the second voltage output.

13. The Rogowski coil assembly of claim 1, wherein the first printed circuit board assembly does not completely surround the conductor, and the second printed circuit board assembly does not completely surround the conductor.

14. The Rogowski coil assembly of claim 1, wherein the first, second, third, and fourth sections of coil are formed by depositing metal onto the first, second, third, and fourth circuit boards, respectively.

15. The Rogowski coil assembly of claim 14, wherein the metal is copper.