Wire degradation testing system

• US 6,225,811 B1
• Filed: 03/30/1999
• Issued: 05/01/2001
• Est. Priority Date: 03/30/1998
• Status: Expired due to Fees

• Current Assignee: Lectromechanical Design Company
• Original Assignee: Lectromechanical Design Company
• Inventors: Linzey, William G., Bruning, Armin M.
• Primary Examiner(s): Karlsen, Ernest
• Assistant Examiner(s): Deb, Anjan K
• Application Number:
  US09/281,214
• Time in Patent Office: 763 Days
• Field of Search: 324/544, 324/541, 324/539, 324/540, 324/134
• US Class Current: 324/544
• CPC Class Codes: G01R 31/58 Testing of lines, cables or conductors testing of electric windings G01R31/72

Abstract

A part of a wire is tested, in situ, for degradation. The part of the wire is optionally enclosed in a jacket. A conductive medium is disposed on the wire. A test unit has a test elements in contact with the conductor of the wire and with the conductive medium. An attempt is made to induce a current along a path from the test unit, through the conductor, through the conductive medium, and back to the test unit. If a current is induced, degradation is detected. The test unit receives a cable of wires, and a selector switch of the test unit electrically couples a voltage source to selected elements of the cable in turn. Wires are tested in situ in an aircraft or other restrictive location.

Claims

1. A method of testing, in situ in an aircraft, a part of a wire for degradation, said wire including a conductor and insulation, said method comprising:

a. disposing a conductive medium on said part of said wire in situ;

b. providing a first test element in contact with said conductor of said wire;

c. providing a second test element in contact with said conductive medium;

d. testing said wire by applying a voltage to said first test element; and

e. when said testing creates a current detectable at one of said first test element and said second test element, determining said insulation to be degraded;

wherein said wire remains rigidly installed in situ in said aircraft during said steps a-e.

2. The method of testing a part of a wire as set forth in claim 1, wherein said conductive medium comprises water.

3. The method of testing a part of a wire as set forth in claim 1, further comprising:

enclosing said part of said wire in a jacket; and

performing said disposing step by introducing into said jacket said conductive medium.

4. The method of testing a part of a wire as set forth in claim 1, further comprising removing said conductive medium from said wire.

5. The method of testing part of a wire as set forth in claim 4, wherein said step of removing said conductive medium comprises vacuuming said conductive medium.

6. The method of testing part of a wire as set forth in claim 5, further comprising a step of directing pressurized air toward said conductive medium.

7. The method of testing part of a wire as set forth in claim 1, wherein said conductive medium comprises a substance conductive in a liquid form and substantially non-conductive in a solid form.

8. The method of testing part of a wire as set forth in claim 7, wherein said substance is salt.

13. An apparatus for testing, in situ, a part of a wire for degradation, said wire including a conductor and insulation, said apparatus comprising:

a first test element in contact with said conductor of said wire in situ;

a second test element in contact with a conductive medium on said part of said wire in situ; and

a test unit electrically coupled with said first test element and said second test element;

wherein said test unit tests said part of said wire for degradation by detecting a current flowing along a path including said first test element, said conductive medium, and said second test element; and

wherein said test unit has a test circuit comprising;

a voltmeter connected across said first test element and said second test element;

a polarity switch connected in parallel with said voltmeter;

a momentary connection switch; and

a voltage selection circuit connected in parallel with said polarity switch.

9. The apparatus for testing a part of a wire as set forth in any one of claims 13-15, further comprising a jacket holding said conductive medium on said part of said wire.

10. The apparatus for testing a part of a wire as set forth in claim 9, further comprising means for removing said conductive medium from said jacket.

11. The apparatus for testing a part of a wire as set forth in any one of claims 13-15, further comprising said conductive medium being water.

12. The apparatus for testing a part of a wire as set forth in any one of claims 13-15, wherein said test unit comprises:

a voltage source, a cable receptor, and a selector;

said cable receptor being adapted to receive a cable connector of a cable that includes said wire and other wires, said wire and said other wires defining a plurality of wires of said cable;

said cable receptor including a plurality of elements, each of said elements being disposed so as to be electrically coupled with a corresponding one of said plurality of wires when said cable connector is disposed in said cable receptor; and

said selector switch electrically coupling said voltage source to a selected one of said elements of said cable receptor.

14. An apparatus for testing, in situ, a part of a wire for degradation, said wire including a conductor and insulation, said apparatus comprising:

a first test element in contact with said conductor of said wire in situ;

a second test element in contact with a conductive medium on said part of said wire in situ; and

a test unit electrically coupled with said first test element and said second test element;

wherein said test unit tests said part of said wire for degradation by detecting a current flowing along a path including said first test element, said conductive medium, and said second test element; and

wherein said test unit has a test circuit comprising;

a voltage selector circuit in parallel with a polarity switch, said voltage selector circuit having a terminal providing no voltage;

said polarity switch being connected between said first test element and a voltmeter;

a sensitivity selection circuit in parallel with said voltmeter; and

an ammeter connected between said voltmeter and said second test element.

15. An apparatus for testing, in situ, a part of a wire for degradation, said wire including a conductor and insulation, said apparatus comprising:

a first test element in contact with said conductor of said wire in situ;

a second test element in contact with a conductive medium on said part of said wire in situ; and

a test unit electrically coupled with said first test element and said second test element;

wherein said test unit tests said part of said wire for degradation by detecting a current flowing along a path including said first test element, said conductive medium, and said second test element; and

wherein said test unit has a test circuit comprising;

a voltage selector circuit in parallel with a polarity switch, said voltage selector circuit having a terminal providing no voltage;

said polarity switch being connected between said second test element and a voltmeter;

a sensitivity selection circuit in parallel with said voltmeter; and

an ammeter connected between said voltmeter and said first test element.