Shunt fault tester for multiconductor cable

Claim 2

Apparatus (FIG. 2) to test a wire pair (TIP, RING) from a multiconductor cable having a shield (SHIELD) for a resistive shunt fault (R F ) located between first (A) and second (B) test positions and for determining the resistance (R 1 ) of one wire (RING) between said fault and said first test position, said apparatus CHARACTERIZED BY: means at said first position comprising an ohmmeter (111) connected between said one wire (103) and said shield (105), and means at said second position comprising operational amplifier means (112) having its noninverting (+) input connected to said shield (106), its inverting (-) input connected to said one wire (104), its output connected to the other wire (102) from said pair and its common (176) connected to said shield (106), wherein the output of said ohmmeter is indicative of said resistance.

Claim 3

Apparatus (FIG. 6) to test a wire pair (TIP,RING) from a multiconductor cable having a shield (SHIELD) for a resistive shunt fault (R F ) located between first (A) and second (B) test positions and for determining the resistance (R 1 ) of one wire (RING) between said fault and said first test position, said apparatus CHARACTERIZED BY: means at said first position comprising a voltmeter (113) connected between said one wire (103) and said shield (105), and operational amplifier means (112) having its noninverting (+) input connected to said shield (105), its inverting (-) input connected to the mate of said one wire (101), its output connected to said one wire (103) and its common (176) connected to said shield (105), and means at said second position comprising a current source (114) connected between said one wire (104) and said shield (106), wherein the output of said voltmeter is indicative of said resistance.

Claim 4

Apparatus (FIG. 6) to test a wire pair (TIP,RING) from a multiconductor cable having a shield (SHIELD) for a resistive shunt fault (R F ) located between first (A) and second (B) test positions and for determining the resistance (R 1 ) of one wire (RING) between said fault and said first test position, said apparatus CHARACTERIZED BY: means at said first position comprising a voltmeter (113) connected between said one wire (103) and said shield (105), and operational amplifier means (112) having its noninverting (+) input connected to said shield (105), its inverting (-) input connected to the mate of said one wire (101), its output connected to said one wire (103) and its common (176) connected to said shield (105), and means at said second position comprising a current source (114) connected between said one wire (104) and said shield (106), wherein the output of said voltmeter is indicative of said resistance.

Claim 5

Apparatus (FIG. 3) to test a wire pair (TIP, RING) from a multiconductor cable having a shield (SHIELD) and at least one other conductor (GOOD) paralleling said pair for a resistive shunt fault (R F ) located between first (A) and second (B) test positions and for determining the resistance (R 1 ) of one wire (RING) between said fault and said first test position, said apparatus CHARACTERIZED BY: means at said first position comprising an ohmmeter (111) connected between said one wire (103) and the said shield (105) and means (177) for shorting said other conductor (109) to said shield (105), and means at said second position comprising operational amplifier means (112) having its noninverting (+) input connected to said conductor (110), its inverting (-) input connected to said one wire (104), its output connected to the other wire (102) from said pair, and its common (176) connected to said shield (106), wherein the output of said ohmmeter is indicative of said resistance.

Claim 6

Apparatus (FIG. 3) to test a wire pair (TIP, RING) from a multiconductor cable having a shield (SHIELD) and at least one other conductor (GOOD) paralleling said pair for a resistive shunt fault (R F ) located between first (A) and second (B) test positions and for determining the resistance (R 1 ) of one wire (RING) between said fault and said first test position, said apparatus CHARACTERIZED BY: means at said first position comprising an ohmmeter (111) connected between said one wire (103) and the said shield (105) and means (177) for shorting said other conductor (109) to said shield (105), and means at said second position comprising operational amplifier means (112) having its noninverting (+) input connected to said conductor (110), its inverting (-) input connected to said one wire (104), its output connected to the other wire (102) from said pair, and its common (176) connected to said shield (106), wherein the output of said ohmmeter is indicative of said resistance.

Claim 7

Apparatus (FIG. 4) to test a wire pair (TIP, RING) from a multiconductor cable having a shield (SHIELD) and at least one other conductor (GOOD) paralleling said pair for a resistive shunt fault (R F ) located between first (A) and second (B) test positions and for determining the resistance (R 1 ) of one wire (RING) between said fault and said first test position, said apparatus CHARACTERIZED BY: means at said first position comprising: a voltmeter (113) connected between said one wire (103) and said other conductor (109), and a current source (114) connected between said one wire (103) and said shield (105), and means at said second position comprising means (177) for shorting said other conductor (110) to said shield (106), and operational amplifier means (112) having its noninverting (+) input connected to said conductor (110), its inverting (-) input connected to said one wire (104), its output connected to the other wire (102) from said pair, and its common (176) connected to said shield (106), wherein the output of said voltmeter is indicative of said resistance.

Claim 8

Apparatus (FIG. 4) to test a wire pair (TIP, RING) from a multiconductor cable having a shield (SHIELD) and at least one other conductor (GOOD) paralleling said pair for a resistive shunt fault (R F ) located between first (A) and second (B) test positions and for determining the resistance (R 1 ) of one wire (RING) between said fault and said first test position, said apparatus CHARACTERIZED BY: means at said first position comprising: a voltmeter (113) connected between said one wire (103) and said other conductor (109), and a current source (114) connected between said one wire (103) and said shield (105), and means at said second position comprising means (177) for shorting said other conductor (110) to said shield (106), and operational amplifier means (112) having its noninverting (+) input connected to said conductor (110), its inverting (-) input connected to said one wire (104), its output connected to the other wire (102) from said pair, and its common (176) connected to said shield (106), wherein the output of said voltmeter is indicative of said resistance.

Claim 9

Apparatus (FIG. 5) to test a wire pair (TIP, RING) from a multiconductor cable having a shield (SHIELD) and at least one other conductor (GOOD) paralleling said pair for a resistive shunt fault (R F ) located between first (A) and second (B) test positions and for determining the resistance (R 1 ) of one wire (RING) between said fault and said first test position, said apparatus CHARACTERIZED BY: means at said first position comprising: operational amplifier means (112) having its noninverting (+) input connected to its common (176), its inverting (-) input connected to said other conductor (109), and its output connected to the other wire (101) of said pair, and an ohmmeter (111) connected between said one wire (103) and said common, and means at said second position for shorting said one wire (104) to said conductor (110), wherein the reading of said ohmmeter is indicative of said resistance.

Claim 10

Apparatus (FIG. 5) to test a wire pair (TIP, RING) from a multiconductor cable having a shield (SHIELD) and at least one other conductor (GOOD) paralleling said pair for a resistive shunt fault (R F ) located between first (A) and second (B) test positions and for determining the resistance (R 1 ) of one wire (RING) between said fault and said first test position, said apparatus CHARACTERIZED BY: means at said first position comprising: operational amplifier means (112) having its noninverting (+) input connected to its common (176), its inverting (-) input connected to said other conductor (109), and its output connected to the other wire (101) of said pair, and an ohmmeter (111) connected between said one wire (103) and said common, and means at said second position for shorting said one wire (104) to said conductor (110), wherein the reading of said ohmmeter is indicative of said resistance.

Claim 11

Apparatus as recited in claims 1, 3 or 5 wherein said ohmmeter operates at a single, low frequency and is frequency selective.

Claim 12

Apparatus as recited in claims 2 or 4 wherein said current source operates at a single, low frequency and said voltmeter is frequency selective.

Claim 13

Apparatus (FIG. 6) to estimate the location of a shunt fault (R F ) along a pair of conductors (TIP, RING) spanning two test positions (A and B), each of said conductors having a terminal node (101,102 and 103,104) accessible at each of said test positions and a corresponding fault node (107 and 108) associated with said fault, said test positions being interconnected with an electrical path (SHIELD) having an end node (105 and 106) accessible at each of said test positions, said apparatus CHARACTERIZED BY: first means (114), located at the first of said test positions (B) and connected to one said terminal node (104) and said end node (106), for supplying constant current between said one said terminal node (104) and said end node (106), second means (112), located at the second of said test positions (A) and connected to each said terminal node (101 and 103) and said end node (105), for virtually interconnecting each said fault node (107 and 108) with one said terminal node (101) and said end node (105), and for providing a current path between the other said terminal node (103) and said end node (105), and third means (113), located at said second of said test positions, for measuring the voltage generated between said end node (105) and said other said node (103) due to said constant current, wherein said voltage is indicative of the resistance of one of said conductors between said second of said test positions and said fault.

Claim 14

Apparatus (FIG. 6) to estimate the location of a shunt fault (R F ) along a pair of conductors (TIP, RING) spanning two test positions (A and B), each of said conductors having a terminal node (101,102 and 103,104) accessible at each of said test positions and a corresponding fault node (107 and 108) associated with said fault, said test positions being interconnected with an electrical path (SHIELD) having an end node (105 and 106) accessible at each of said test positions, said apparatus CHARACTERIZED BY: first means (114), located at the first of said test positions (B) and connected to one said terminal node (104) and said end node (106), for supplying constant current between said one said terminal node (104) and said end node (106), second means (112), located at the second of said test positions (A) and connected to each said terminal node (101 and 103) and said end node (105), for virtually interconnecting each said fault node (107 and 108) with one said terminal node (101) and said end node (105), and for providing a current path between the other said terminal node (103) and said end node (105), and third means (113), located at said second of said test positions, for measuring the voltage generated between said end node (105) and said other said node (103) due to said constant current, wherein said voltage is indicative of the resistance of one of said conductors between said second of said test positions and said fault.

Claim 15

Apparatus (FIG. 2) to estimate the location of a shunt fault (R F ) along a pair of conductors (TIP,RING), spanning two test positions (A and B), each of said conductors having a terminal node (101,102 and 103,104) accessible at each of said test positions and a corresponding fault node (107 and 108) associated with said fault, said test positions being interconnected with an electrical path (SHIELD) having an end node (105 and 106) accessible at each of said test positions, said apparatus CHARACTERIZED BY: first means (111), located at the first of said test positions (A) and connected to one said terminal node (103) and said end node (105), for measuring the resistance between said one said terminal node (103) and said end node (105), and second means (112), located at the other of said test positions (B) and connected to each said terminal node (102 and 104) and said end node (106), for virtually interconnecting one said fault node (108) with one said terminal node (104) and said end node (106) and for providing an electrical path between the other said terminal node (102) and said end node (106), wherein said resistance comprises the resistance of one of said conductors between said first of said test positions and said fault.

Claim 16

Apparatus (FIG. 2) to estimate the location of a shunt fault (R F ) along a pair of conductors (TIP,RING), spanning two test positions (A and B), each of said conductors having a terminal node (101,102 and 103,104) accessible at each of said test positions and a corresponding fault node (107 and 108) associated with said fault, said test positions being interconnected with an electrical path (SHIELD) having an end node (105 and 106) accessible at each of said test positions, said apparatus CHARACTERIZED BY: first means (111), located at the first of said test positions (A) and connected to one said terminal node (103) and said end node (105), for measuring the resistance between said one said terminal node (103) and said end node (105), and second means (112), located at the other of said test positions (B) and connected to each said terminal node (102 and 104) and said end node (106), for virtually interconnecting one said fault node (108) with one said terminal node (104) and said end node (106) and for providing an electrical path between the other said terminal node (102) and said end node (106), wherein said resistance comprises the resistance of one of said conductors between said first of said test positions and said fault.