Wire test method and apparatus
First Claim
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1. A method of testing, in situ, 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 alternately applying and removing a voltage to said first test element at a rate of at least 5 Hz;
e. when said testing determines the presence of a leakage current at one of said first test element and said second test element, determining said insulation to be degraded;
wherein said wire remains rigidly installed it situ during said steps a-e.
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Abstract
A wire testing method and apparatus test wire in-situ in a rigidly installed state, such as an aircraft. An apparatus for rapidly switching the excitation voltage and ground compensates for stray currents. The apparatus outputs a stray current signal, a detected signal, and a difference signal indicative of a measurement with stray current signal removed.
13 Citations
18 Claims
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1. A method of testing, in situ, a part of a wire for degradation, said wire including a conductor and insulation, said method comprising:
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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 alternately applying and removing a voltage to said first test element at a rate of at least 5 Hz;
e. when said testing determines the presence of a leakage current at one of said first test element and said second test element, determining said insulation to be degraded;
wherein said wire remains rigidly installed it situ during said steps a-e. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
enclosing said part of said wire in a jacket; and
performing said disposing step by introducing into said jacket said conductive medium.
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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.
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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.
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6. The method of testing part of a wire as set forth in claim 5, further comprising a step of directing pressure air toward said conductive medium.
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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 fluid form and substantially non-conductive in a solid form.
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8. The method of testing part of a wire as set forth in claim 7, wherein said substance is salt.
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9. An apparatus for testing, in situ, a part of a wire for degradation, said wire including a conductor and insulation, said apparatus comprising:
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a first test element in contact with said conductor of said wire in situ;
a second test clement in contact with a conductive medium on said part of said wire in situ; and
a test unit electrically coupled with said first test clement 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 comprises;
a control signal source outputting a control signal;
a voltage supply circuit;
a measurement circuit for rectifying detected readings, comprising;
an ammeter, and a primary measurement circuit having detectors including an in circuit detector and an out of circuit detector, said primary measurement circuit receiving, as an input, a measurement received from said ammeter;
a switching circuit for synchronously switching, under control of said control signal, said voltage supply circuit and said detectors of said measurement circuit for rectifying detected readings. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18)
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 supply circuit to a selected one of said elements of said cable receptor.
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Specification