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US4399402A
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Resistive fault sectionalization
Assignee: AT&T Inc
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Filing: 1981-08-31
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Granted: 1983-08-16
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Expires: 2001-08-31
Abstract
Abstract A methodology, and associated circuitry, for locating a resistive shunt fault coupling the cable shield and the conductors of the cable pair under test comprises the steps of: (i) measuring the open-circuited DC resistance (A 1 and A 2 ) of the pair from test locations (A and B) which straddle the fault; (ii) measuring the short-circuited DC resistance (A 3 ) of the pair from one of the test points (A or B); and (iii) evaluating the resistance of one conductor of the pair between the fault and the location of the short circuit measurement according to a predetermined quadratic expression involving the three measured quantities. Sensitivity of the measurement technique is reduced by adding a resistor in series with said pair, at either location A or B, so that A 2 is substantially equal to A 1 .
Inventors
- 👤 James A. Pelletier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:48
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/08; G01R31/081; G01R31/083; G01R31/50; G01R31/52
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
145 words
A method for testing a cable pair (TIP,RING) to locate a shunt resistance fault (R F ) between first (A) and second (B) test positions by determining the conductor (TIP or RING) resistance (R X ) between said fault and said second test position, said method CHARACTERIZED BY THE STEPS OF measuring the DC resistance (A 1 ) of said pair at said first test position with said pair open-circuited at said second test position, measuring the DC resistance (A 2 ) of said pair at said second test position with said pair open-circuited at said first test position, measuring the DC resistance (A 3 ) of said pair at said second test position with said pair short-circuited at said first test position, and determining the value of said resistance (R X ) from the expression R.sub.X.sup.2 -A.sub.2 R.sub.X +(A.sub.1 /4) (A.sub.3 -A.sub.2)+(A.sub.2 /2).sup.2 =0.
Claim 2
Independent Claim
145 words
A method for testing a cable pair (TIP,RING) to locate a shunt resistance fault (R F ) between first (A) and second (B) test positions by determining the conductor (TIP or RING) resistance (R X ) between said fault and said second test position, said method CHARACTERIZED BY THE STEPS OF measuring the DC resistance (A 1 ) of said pair at said first test position with said pair open-circuited at said second test position, measuring the DC resistance (A 2 ) of said pair at said second test position with said pair open-circuited at said first test position, measuring the DC resistance (A 3 ) of said pair at said second test position with said pair short-circuited at said first test position, and determining the value of said resistance (R X ) from the expression R.sub.X.sup.2 -A.sub.2 R.sub.X +(A.sub.1 /4) (A.sub.3 -A.sub.2)+(A.sub.2 /2).sup.2 =0.
Claim 3
Independent Claim
169 words
A method for testing a cable pair (TIP,RING) to locate a shunt resistance fault (R F ) between first (A) and second (B) test positions by determining the conductor (TIP or RING) resistance (R X ) between said fault and said second test position, said method CHARACTERIZED BY THE STEPS OF measuring the DC resistance (A 1 ) of said pair at said first test position with said pair open-circuited at said second test position, adding a preselected resistance (±R) in series with one conductor (TIP or RING) of said pair to form a series combination, measuring the DC resistance (A 2 ) of said series combination at said second test position with said pair open-circuited at said first test position, measuring the DC resistance (A 3 ) of said series combination at said second test position with said pair short-circuited at said first test position, and determining the value of said resistance (R X ) from the expression (R.sub.X ±R).sup.2 -A.sub.2 (R.sub.X ±R)+(A.sub.1 /4) (A.sub.3 -A.sub.2)+(A.sub.2 /2).sup.2 =0.
Claim 4
Independent Claim
169 words
A method for testing a cable pair (TIP,RING) to locate a shunt resistance fault (R F ) between first (A) and second (B) test positions by determining the conductor (TIP or RING) resistance (R X ) between said fault and said second test position, said method CHARACTERIZED BY THE STEPS OF measuring the DC resistance (A 1 ) of said pair at said first test position with said pair open-circuited at said second test position, adding a preselected resistance (±R) in series with one conductor (TIP or RING) of said pair to form a series combination, measuring the DC resistance (A 2 ) of said series combination at said second test position with said pair open-circuited at said first test position, measuring the DC resistance (A 3 ) of said series combination at said second test position with said pair short-circuited at said first test position, and determining the value of said resistance (R X ) from the expression (R.sub.X ±R).sup.2 -A.sub.2 (R.sub.X ±R)+(A.sub.1 /4) (A.sub.3 -A.sub.2)+(A.sub.2 /2).sup.2 =0.
Claim 5
Dependent Claim
25 words
The method as recited in claim 2 further comprising the step of selecting said resistance (±R) so that A 2 essentially equals A 1 .
Claim 6
Dependent Claim
138 words
Testing apparatus for locating a pair fault (R F ) between first (A) and second (B) test positions by determining the conductor (TIP or RING) resistance (R X ) between said fault and said second test location, said apparatus CHARACTERIZED BY first means at said first location to sequentially configure said pair (i) for measuring the DC resistance (A 1 ), (ii) by open-circuiting and (iii) by short-circuiting said pair, respectively, and second means at said second location, operating simultaneously with said first means, to configure said pair (i) by open-circuiting said pair, (ii) for measuring the DC resistance (A 2 ), and (iii) for measuring the DC resistance (A 3 ), respectively, of said pair, wherein said resistance (R X ) is a solution to the quadratic expression R.sub.X.sup.2 -A.sub.2 R.sub.X +(A.sub.1 /4) (A.sub.3 -A.sub.2)+(A.sub.2 /2).sup.2 =0.
Claim 7
Dependent Claim
138 words
Testing apparatus for locating a pair fault (R F ) between first (A) and second (B) test positions by determining the conductor (TIP or RING) resistance (R X ) between said fault and said second test location, said apparatus CHARACTERIZED BY first means at said first location to sequentially configure said pair (i) for measuring the DC resistance (A 1 ), (ii) by open-circuiting and (iii) by short-circuiting said pair, respectively, and second means at said second location, operating simultaneously with said first means, to configure said pair (i) by open-circuiting said pair, (ii) for measuring the DC resistance (A 2 ), and (iii) for measuring the DC resistance (A 3 ), respectively, of said pair, wherein said resistance (R X ) is a solution to the quadratic expression R.sub.X.sup.2 -A.sub.2 R.sub.X +(A.sub.1 /4) (A.sub.3 -A.sub.2)+(A.sub.2 /2).sup.2 =0.
Claim 8
Dependent Claim
156 words
Testing apparatus for locating a pair fault (R F ) between first (A) and second (B) test locations by determining the conductor (TIP or RING) resistance (R X ) between said fault and said second test location, said apparatus CHARACTERIZED BY first means at said first location to sequentially configure said pair (i) for measuring the DC resistance (A 1 ), by (ii) open-circuiting and (iii) by short-circuiting said pair, respectively, and second means at said second location, operating simultaneously with said first means, to configure said pair (i) by open-circuiting said pair, (ii) by adding a preselected resistor (±R) in series with one conductor of said pair and measuring the DC resistance (A 2 ) of the series combination, and (iii) by measuring the DC resistance (A 3 ) of said combination, wherein said resistance (R X ) is a solution to the quadratic expression (R.sub.X ±R).sup.2 -A.sub.2 (R.sub.X ±R)+(A.sub.1 /4) (A.sub.3 -A.sub.2)+(A.sub.2 /2).sup.2 -0.
Claim 9
Dependent Claim
156 words
Testing apparatus for locating a pair fault (R F ) between first (A) and second (B) test locations by determining the conductor (TIP or RING) resistance (R X ) between said fault and said second test location, said apparatus CHARACTERIZED BY first means at said first location to sequentially configure said pair (i) for measuring the DC resistance (A 1 ), by (ii) open-circuiting and (iii) by short-circuiting said pair, respectively, and second means at said second location, operating simultaneously with said first means, to configure said pair (i) by open-circuiting said pair, (ii) by adding a preselected resistor (±R) in series with one conductor of said pair and measuring the DC resistance (A 2 ) of the series combination, and (iii) by measuring the DC resistance (A 3 ) of said combination, wherein said resistance (R X ) is a solution to the quadratic expression (R.sub.X ±R).sup.2 -A.sub.2 (R.sub.X ±R)+(A.sub.1 /4) (A.sub.3 -A.sub.2)+(A.sub.2 /2).sup.2 -0.
Claim 10
Dependent Claim
22 words
The apparatus as recited in claim 5 wherein said resistor (±R) is chosen so that A 2 essentially equals A 1 .
Claim 11
Dependent Claim
168 words
Wire-pair apparatus for testing a resistive fault (R F ) located between first (A) and second (B) test locations and for determining the resistance (R X ) of one wire (TIP or RING) between said fault and said second test location, said apparatus CHARACTERIZED BY first means at said first location having three sequential modes of operation including: a first mode for measuring the DC resistance (A 1 ) of said pair; a second mode for disconnecting said first means from said pair; and a third mode for shorting said pair, and second means at said second location operating in one-to-one correspondence to said modes for: disconnecting said second means from said pair during said first mode; measuring the DC resistance (A 2 ) of said pair during said second mode; and measuring the DC resistance (A 3 ) of said pair during said third mode, wherein said resistance (R X ) is a solution to the quadratic expression R.sub.X.sup.2 -A.sub.2 R.sub.X +(A.sub.1 /4) (A.sub.3 -A.sub.2)+(A.sub.2 /2).sup.2 =0.
Claim 12
Dependent Claim
168 words
Wire-pair apparatus for testing a resistive fault (R F ) located between first (A) and second (B) test locations and for determining the resistance (R X ) of one wire (TIP or RING) between said fault and said second test location, said apparatus CHARACTERIZED BY first means at said first location having three sequential modes of operation including: a first mode for measuring the DC resistance (A 1 ) of said pair; a second mode for disconnecting said first means from said pair; and a third mode for shorting said pair, and second means at said second location operating in one-to-one correspondence to said modes for: disconnecting said second means from said pair during said first mode; measuring the DC resistance (A 2 ) of said pair during said second mode; and measuring the DC resistance (A 3 ) of said pair during said third mode, wherein said resistance (R X ) is a solution to the quadratic expression R.sub.X.sup.2 -A.sub.2 R.sub.X +(A.sub.1 /4) (A.sub.3 -A.sub.2)+(A.sub.2 /2).sup.2 =0.
References Cited (Backward Citations)
US3234459A
Cited
US3248646A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-08-15 | 1987-02-14 | 1987-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-15 | 1991-02-14 | 1991-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-15 | 1995-02-14 | 1995-08-16 | $7700.00 | Window Closed / Lapsed |