Cable mounted magnetic core assembly

• US 4,456,873 A
• Filed: 08/04/1981
• Issued: 06/26/1984
• Est. Priority Date: 08/04/1981
• Status: Expired due to Term

• Current Assignee: Edmund O. Schweitzer Jr
• Original Assignee: Edmund O. Schweitzer Jr
• Inventors: Schweitzer, Edmund O. Jr.
• Primary Examiner(s): Karlsen, Ernest F.
• Application Number:
  US06/289,916
• Time in Patent Office: 1,057 Days
• Field of Search: 324/127, 324/51, 324/133, 336/20, 336/175, 336/176
• US Class Current: 324/543
• 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 19/16509 using electromagnetic relays, e.g. reed relay magnetically driven reeds G01R9/06

Abstract

A fault indicator for indicating the occurrence of a fault current in an electrical conductor includes a core assembly which attaches a circuit module to a monitored conductor and provides a concentrated magnetic flux indicative of the current level in the conductor. A magnetic reed switch in the circuit module responds to the magnetic flux in the core assembly to condition an indicator in a remote indicator module to a fault-indicating state in the event of a fault. To facilitate installation and removal of the circuit module from the conductor, the core assembly is formed by a plurality of laminations secured together and arranged in a generally rectangular configuration with their ends juxtaposed along one side thereof and joined with magnetically conductive interlocking coupling members. A spring spanning the remaining opposed sides of the core biases the coupling members into engagement and allows the structure to be fitted over conductors of various sizes, while maintaining a close operative association between the conductor and the magnetic reed switch in the circuit module.

Claims

1. A fault indicator for indicating the occurrence of a fault current in an electrical conductor, comprising:

magnetic core means comprising a plurality of elongated strips of resilient magnetic material arranged side by side and joined at the ends thereof to form a magnetic core;

said magnetic core being formed into a closed loop having first, second, third and fourth sides, said first, second and third sides being generally rectilinear, said first side being generally opposite said second side, and said third side joining said first and second sides, said magnetic core being dimensioned to receive within said closed loop said electrical conductor;

interlocking connection means disposed along said third side for establishing a separable connection between segments of said third side, said connection being locked against lateral displacement upon said segments being urged toward axial engagement;

biasing means comprising a spring member extending between said first side and said second side for drawing said sides together whereby said segments are urged toward axial engagement, said spring member being positioned to engage the conductor opposite from said third side to urge the conductor into contact with said third side;

current-responsive means disposed along said third side of said magnetic core in magnetic communication with the conductor for providing a control effect upon the occurrence of a fault current in the conductor; and

means responsive to said control effect for providing a fault indication.

2. A fault indicator as defined in claim 1 wherein said connection means are disposed at one extreme of said third side, between said first side and said second side, and said current-responsive means are disposed between said connection means and said second side.

3. A fault indicator as defined in claim 1 wherein said current-responsive means comprise a magnetic reed switch.

4. A fault indicator as defined in claim 1 wherein said circuit means require a source of excitation, and wherein a magnetic winding is provided on said third side for providing said excitation.

5. A fault indicator as defined in claim 2 wherein said circuit means require a source of excitation, and wherein a magnetic pick-up winding is disposed on said third side between said connection means and said second side for providing said excitation.

6. A fault indicator for indicating the occurrence of a fault current in an electrical conductor, comprising:

magnetic core means comprising a plurality of elongated strips of resilient magnetic material arranged side-by-side and joined at the ends thereof to form a magnetic core;

said magnetic core being formed into a closed loop of generally rectangular form having first, second, third and fourth generally rectilinear sides, said first side being opposite said second side, said third side being opposite said fourth side, and said third side joining said first and second sides, said magnetic core being dimensioned to receive within said closed loop said electrical conductor;

interlocking connection means disposed along said third side for establishing a separable connection between segments of said third side, said connection being locked against lateral displacement upon said segments being urged toward axial engagement;

biasing means comprising a spring member extending between said first side and said second side for drawing said sides together whereby said segments are urged toward axial engagement, said spring member being positioned to engage the conductor opposite from said third side to urge the conductor into contact with said third side;

current-responsive means disposed along said third side of said magnetic core in magnetic communication with the conductor for providing a control effect upon the occurrence of a fault current in the conductor;

circuit means responsive to said control effect for providing a fault indication, said circuit means being operative from an applied excitation source; and

excitation means comprising a magnetic winding on said third side of said magnetic core for supplying excitation to said circuit means.

7. A fault indicator as defined in claim 6 wherein said connection means are disposed at one end of said third side, between said first side and said second side, and said current-responsive means and said magnetic winding are disposed between said connection means and said second side.

8. A magnetic core assembly as defined in claim 7 wherein said current-responsive means comprise a magnetic reed switch.

9. A fault indicator for indicating the occurrence of a fault current in an electrical conductor, comprising:

magnetic core means comprising a plurality of elongated strips of resilient magnetic material arranged side-by-side and joined at the ends thereof to form a magnetic core;

said magnetic core being formed into a closed loop having a first, second, third and fourth sides, said first, second and third sides being generally rectilinear, said first side being opposite said second side, and said third side joining said first and second sides, said magnetic core being dimensioned to receive within said closed loop said electrical conductor;

interlocking connection means disposed along said third side for establishing a separable connection between segments of said third side, said connection being locked against lateral displacement upon said segments being urged toward axial engagement;

biasing means comprising a spring member extending between said first side and said second side for drawing said sides together whereby said segments are urged toward axial engagement, said spring member being positioned to engage the conductor opposite from said third side to urge the conductor into contact with said third side;

current-responsive means disposed along said third side of said magnetic core in magnetic communication with the conductor for providing a control effect upon the occurrence of a fault current in the conductor;

circuit means operable from an applied excitation current and responsive to said control effect for providing a fault indication in response to said control effect; and

excitation means comprising a magnetic winding disposed on said third side of said core for providing excitation current to said circuit means.

10. A fault indicator as defined in claim 9 wherein said connection means are disposed at one end of said third side, between said first side and said second side, and said current-responsive means are disposed between said connection means and said second side.

11. A fault indicator as defined in claim 10 wherein said current-responsive means comprise a magnetic reed switch.

12. A magnetic core assembly for installation on an electrical conductor, comprising:

a plurality of elongated strips of resilient magnetic material arranged side-by-side and joined at the ends thereof to form a magnetic core;

said magnetic core being formed into a closed loop having first, second, third and fourth sides, said first, second and third sides being generally rectilinear, said first side being generally opposite said second side, and said third side joining said first and second sides, said core being dimensioned to receive within said closed loop said electrical conductor;

interlocking connection means disposed along said third side for establishing a separable connection between segments of said third side, said connection being locked against lateral displacement upon said segments being urged toward axial engagement; and

biasing means comprising a spring member extending between said first side and said second side for drawing said sides together whereby said segments are urged toward axial engagement, said spring member being positioned to engage the conductor opposite from said third side to urge the conductor into contact with said third side.

13. A magnetic core assembly as defined in claim 12 wherein said biasing means comprise a helical spring.

14. A magnetic core assembly as defined in claim 12 including current-responsive means in magnetic communication with the conductor for providing a control effect dependent on the current level in the conductor.

15. A magnetic core assembly as defined in claim 14 wherein said current-responsive means are disposed along said third side of said magnetic core.

16. A magnetic core assembly as defined in claim 12 wherein said connection means are disposed at one extreme of said third side, between said first side and said second side.

17. A magnetic core assembly as defined in claim 12 wherein said magnetic core is generally rectangular in form, and includes a generally rectilinear fourth side generally opposite said third side.

18. A magnetic core assembly as defined in claim 15 wherein said connection means are disposed at one end of said third side, between said first side and said second side, and said current-responsive means are disposed between said connection means and said second side.

19. A magnetic core assembly as defined in claim 15 wherein said current-responsive means comprise a magnetic reed switch.

20. A magnetic core assembly as defined in claim 15 wherein said current-responsive means comprise a magnetic winding.

21. A magnetic core assembly for installation on an electrical conductor, comprising:

a plurality of elongated strips of resilient magnetic material arranged side-by-side and joined at the ends thereof to form a magnetic core;

said magnetic core being formed into a closed loop of generally rectangular form having first, second, third and fourth sides, said first, second and third sides being generally rectilinear, said first side being generally opposite said second side, and said third side joining said first and second sides, said magnetic core being dimensioned to receive within said closed loop said electrical conductor;

interlocking connection means disposed along said third side for establishing a separable connection between segments of said third side, said connection being locked against lateral displacement upon said segments being urged toward axial engagement; and

biasing means comprising a spring member extending between said first side and said second side for drawing said sides together whereby said segments are urged toward axial engagement, said spring member being positioned to engage the conductor opposite from said third side to urge the conductor into contact with said third side.

22. A magnetic core assembly as defined in claim 21 wherein said biasing means comprise a helical spring.

23. A magnetic core assembly as defined in claim 21 including current-responsive means in magnetic communication with the conductor for providing a control effect dependent on the current level in the conductor.

24. A magnetic core assembly as defined in claim 23 wherein said current-responsive means are disposed along said third side of said magnetic core.

25. A magnetic core assembly as defined in claim 21 wherein said interlocking connection means are disposed at one extreme of said third side, between said first side and said second side.

26. A magnetic core assembly as defined in claim 24 wherein said connection means are disposed at one extreme of said third side, between said first side and said second side, and said current-responsive means are disposed between said connection means and said second side.

27. A magnetic core assembly as defined in claim 26 wherein said current-responsive means include a magnetic reed switch.

28. A magnetic core assembly as defined in claim 26 wherein said current-responsive means include a magnetic pick-up winding.

29. A magnetic core assembly for installation on an electrical conductor, comprising:

a plurality of elongated strips of resilient magnetic material arranged side-by-side and joined at the ends thereof to form a magnetic core;

31. A magnetic core assembly as defined in claim 29 wherein said connection means are disposed at one end of said third side, between said first side and said second side, and said current-responsive means are disposed between said connection means and said second side.

30. said magnetic core being formed into a closed loop of generally rectangular form and having first, second, third and fourth generally rectilinear sides, said first side being generally opposite said second side, said third side being generally opposite said fourth side, and said third side joining said first and second sides, and said magnetic core being dimensioned to receive within said closed loop said electrical conductor;

interlocking connection means disposed along said third side for establishing a separable connection between segments of said third side, said connection being locked against lateral displacement upon said segments being urged toward axial engagement;

biasing means comprising a spring member extending between said first side and said second side for drawing said sides together whereby said segments are urged toward axial engagement, said spring member being positioned to engage the conductor opposite from said third side to urge the conductor into contact with said third side; and

current-responsive means disposed along said third side of said magnetic core in magnetic communication with the conductor for providing a control effect dependent on the current level in the conductor.

32. A magnetic core assembly as defined in claim 30 wherein said current-responsive means include a magnetic reed switch.

33. A magnetic core assembly as defined in claim 30 wherein said current-responsive means include a magnetic winding.