Probe for use in non-destructive measuring of electrical resistance of a high current electrical connection

• US 5,126,680 A
• Filed: 08/23/1990
• Issued: 06/30/1992
• Est. Priority Date: 08/23/1990
• Status: Expired due to Term

• Current Assignee: Hydro-Quebec (Province of Québec)
• Original Assignee: Hydro-Quebec (Province of Québec)
• Inventors: Morin, Francois, Parker, Michael
• Primary Examiner(s): Harvey, Jack B.
• Assistant Examiner(s): Regan, Maura K.
• Application Number:
  US07/571,262
• Time in Patent Office: 677 Days
• Field of Search: 324/149, 324/713, 324/715, 324/724, 324/72.5
• US Class Current: 324/724
• CPC Class Codes: G01R 1/067 Measuring probes
• CPC Class Codes: G01R 27/205 Measuring contact resistance of connections, e.g. of earth connections

Abstract

A probe for use in non-destructive measuring of electrical resistance of a high current electrical connection between two high current electrical conductors, each of the conductors having a longitudinal exterior surface, the probe comprising: an articulated body being articulated about a longitudinal axis; a plurality of electrodes provided on an interior portion of the articulated body for engaging about the longitudinal exterior surface; connecting means for releaseably connecting the articulating body around the longitudinal exterior surface, the connecting means including resilient means cooperating with the plurality of electrodes for causing the electrodes to resiliently engage the surface, the electrodes being located on the probe body to be arranged substantially evenly around and on the longitudinal exterior surface of the corresponding conductor in a plane substantially perpendicular to a current flow in the conductor; and resistors connected in series with each electrode, each of the resistors having substantially an equal resistance substantially greater than a contact resistance between the corresponding electrode and the corresponding conductor, the resistors being connected to at least one common terminal for connection to a high sensitivity low resistance ohm-meter. The probe makes the measuring easier and more accurate by assuring a good current distribution in the conductors.

Claims

1. A probe for use in non-destructive measuring of electrical resistance of a high current electrical connection between two high current electrical conductors, each of said conductors having a longitudinal exterior surface, the probe comprising:

an articulated body being articulated about a longitudinal axis;

a plurality of electrodes provided on an interior portion of the articulated body for engaging about said longitudinal exterior surface;

connecting means for releasably connecting the articulated body around said longitudinal exterior surface, the connecting means including resilient means cooperating with the plurality of electrodes for causing the electrodes to resiliently engage said surface, the electrodes being located on the probe body to be arranged substantially evenly around and on said longitudinal exterior surface of the corresponding conductor in a plane substantially perpendicular to a current flow in said conductor; and

resistors connected in series with each said electrode, each of said resistors having substantially an equal resistance substantially greater than a contact resistance between the corresponding electrode and the corresponding conductor, said resistors being connected to at least one common terminal for connection to a high sensitivity low resistance ohm-meter.

2. Probe according to claim 1, wherein the articulated body comprises two opposed substantially rectangular members, each said rectangular member having an interior side facing a corresponding interior side, and two longitudinal and two lateral edges said connecting means including means for connecting the two rectangular members together at one of said two longitudinal edges and allowing for the two rectangular members to move apart and closer together with said faces being substantially parallel, and wherein said electrodes comprise at least four electrodes provided on at least one lateral row on each of said interior sides, whereby said rectangular members can open and close on said longitudinal exterior surface having two major substantially flat sides.

3. Probe according to claim 2, wherein said at least one lateral row comprises first and second series, said first series being located longitudinally adjacent said second series, the electrodes of one of said series being out of line with the electrodes of the other series to allow for a higher density of a large number of electrodes provided along said at least one lateral row.

4. Probe according to claim 2, wherein said resilient means include springs, and each of said springs is disposed in a cavity provided in an interior portion of said two substantially rectangular members for cooperating with the corresponding electrode.

5. Probe according to claim 2, comprising guard means for protecting ends of said electrodes during placement of the probe on said longitudinal exterior surface, said guard means comprising a guide member connected to said body, said guide member being moveable between a projected position for protecting said ends of said electrodes and a retracted position for allowing said electrodes to contact said longitudinal exterior surface.

6. Probe according to claim 5, wherein said guide member is a rectangular frame surrounding said electrodes provided on one of said two rectangular members, and is resiliently connected to said one of said two rectangular members.

7. Probe according to claim 2, wherein said electrodes have a density substantially equal to a density of strands provided on said two major substantially flat sides.

8. Probe according to claim 1, wherein the articulated body comprises two substantially semi-annular members pivotally connected together at one end of said semi-annular members, whereby said semi-annular members can open and close on the corresponding conductor, and wherein said electrodes are provided on an interior portion of both said semi-annular members and are directed radially inward.

9. Probe according to claim 8, wherein at least one of said conductors has a hexagonal cross-section and each said two substantially semi-annular members has an interior surface made of three surface segments, contiguous ones of said three surface segments forming angles of 120°

.

10. Probe according to claim 9, wherein one electrode is provided substantially in a center portion of each said surface segment.

11. Probe according to claim 9, wherein one of said electrodes is provided on alternate ones of said surface elements.

12. Probe according to claim 8, wherein a spring is disposed in a cavity provided in an interior portion of said semi-annular members for cooperating with a corresponding electrode and for interconnecting said corresponding electrode with said articulated body, said electrodes being retracted into said semi-annular members by natural action of said springs, and said resilient means cause said electrodes to protrude from said interior portion in resistance to said springs, said resilient means comprising a tension strap surrounding said electrodes, so that said electrodes may be retracted during placement of the probe and caused to protrude to contact said longitudinal exterior surface during use.

13. Probe according to claim 1, wherein the articulated body comprises a plurality of annular segment elements flexibly interconnected, whereby said annular segment elements can open and close on a substantially cylindrical multi-strand conductor cable, each said annular segment elements comprising at least one electrode.

14. Probe according to claim 13, wherein said annular segment elements are flexibly interconnected by at least one open arcuate band to which each said annular segment elements is fixed.

15. Probe according to claim 14, wherein three said arcuate bands are provided, a first of said three arcuate bands having one said annular segment element and being hinged to a second and a third of said three circular bands.

16. Probe according to claim 14, wherein said connecting means comprise an adjustable tension strap to be placed around said circular band.

17. Probe according to claim 15, wherein said connecting means comprise an adjustable tension strap to be placed around said circular band.

18. Probe according to claim 14, wherein each of said electrodes comprises a tungsten wire segment provided on a radially inner surface of said annular segment elements, each of said tungsten wire segments being arranged in said plane substantially perpendicular to a current flow such that a side of said wire segments contact said multi-strand conductor cable.

19. Probe according to claim 18, wherein said tungsten wire segments span substantially two strands of said multi-strand conductor cable.

20. Probe according to claim 2, wherein said at least one lateral row consists of two lateral rows on each said interior sides, said two lateral rows being spaced apart longitudinally, a first one of said lateral rows can be used for current injection and the second one of said lateral rows can be used for potential detection, said second one can be located in a direction of current flowing through said first one of said lateral rows, said electrodes comprising at least eight electrodes.

21. Probe according to claim 20, wherein each of said rows comprises first and second series, said first series being located longitudinally adjacent to said second series, the electrodes of one of said series being out of line with the electrodes of the other series to allow for a higher density of a large number of electrodes along said two lateral rows.

22. Probe according to claim 21, wherein said resilient means include springs, each of said springs is disposed in a cavity provided in an interior portion of said two substantially rectangular members for cooperating with the corresponding electrode.

23. Probe according to claim 21, comprising guard means for protecting ends of said electrodes during placement of the probe on said longitudinal exterior surface, said guard means comprising a guide member connected to said body, said guide member being moveable between a projected position for protecting said ends of said electrodes and a retracted position for allowing said electrodes to contact said longitudinal exterior surface.

24. Probe according to claim 21, wherein said guide member is a rectangular frame surrounding said electrodes provided on one of said two rectangular members, and is resiliently connected to said one of said two rectangular members.