Fault indicator having a remote test point at which fault occurrence is indicated by change in magnetic state
First Claim
1. A fault indicator for use in conjunction with a removable magnetically actuated circuit status indicator for providing on the exterior surface of an electrical equipment enclosure a magnetic flux for actuating the indicator following the occurrence of a fault current in an electrical conductor within the enclosure, said indicator comprising, in combination:
- status indicating means including a test point member extending through a wall of the enclosure and forming on the exterior surface thereof a tamper-resistant magnetic test point; and
fault responsive means within the enclosure responsive to the current level in the conductor for producing at said magnetic test point the magnetic flux for actuating the indicator upon the occurrence of a fault current in the conductor.
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Accused Products
Abstract
A fault indicator for use in conjunction with components of a power distribution system contained within a protective enclosure includes a magnetic test point on the exterior surface of the enclosure for indicating the occurrence of a fault in associated circuits of the system. The fault indicator includes a circuit module mounted on a conventional test-point provided on one of the system components, and a magnetic indicator module mounted on the wall of the enclosure. The indicator module includes a magnetizable element which extends through the wall of the housing to provide a magnetic test point. Upon occurrence of a fault in the system, circuitry within the indicator module energizes a first winding in the indicator module to establish a magnetic state of a first polarity at the test point. Upon restoration of power, a reset circuit energizes a second winding to establish a magnetic state of opposite polarity at the test point. A portable test instrument comprising a hand held housing on which a magnetized flag member is rotatably mounted is positioned adjacent the magnetic test point by a lineman to determine circuit status.
54 Citations
46 Claims
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1. A fault indicator for use in conjunction with a removable magnetically actuated circuit status indicator for providing on the exterior surface of an electrical equipment enclosure a magnetic flux for actuating the indicator following the occurrence of a fault current in an electrical conductor within the enclosure, said indicator comprising, in combination:
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status indicating means including a test point member extending through a wall of the enclosure and forming on the exterior surface thereof a tamper-resistant magnetic test point; and fault responsive means within the enclosure responsive to the current level in the conductor for producing at said magnetic test point the magnetic flux for actuating the indicator upon the occurrence of a fault current in the conductor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A fault indicator for use in conjunction with a removable magnetically actuated circuit status indicator for providing on the exterior of an electrical equipment enclosure a magnetic flux for actuating the indicator following the occurrence of a fault current in an electrical conductor within the enclosure, said indicator comprising, in combination:
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status indicating means including a test point member adapted to extend through an aperture in the enclosure and to define a tamper-resistant magnetic test point generally contiguous with the exterior surface of the enclosure, and a magnetic core member of relatively high magnetic retention capability in magnetic communication with said test point member; and fault responsive circuit means within the enclosure responsive to the current level in the conductor and including a magnetic winding in magnetic communication with said core member for magnetizing said core member to provide the magnetic flux for actuating the indicator at said magnetic test point upon occurrence of a fault current in the conductor. - View Dependent Claims (14, 15, 16)
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17. A fault indicator system for providing at the exterior of an electrical equipment enclosure an indication of the occurrence of a fault current in an electrical conductor within the enclosure, said indicator system comprising, in combination:
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status indicating means including a test point member at least partially exposed to the exterior of the enclosure so as to define a tamper-resistant magnetic test point contiguous with the exterior surface of the enclosure; fault responsive means within said enclosure responsive to the current level in the conductor for producing at said test point a fault-indicating magnetic field upon occurrence of a fault current in the conductor; and removable indicator means user-engagable to said magnetic test point and responsive to the fault-indicating magnetic field at said test point for indicating to the user the status of the conductor. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. A fault indicator system for providing at the exterior of an electrical equipment enclosure an indication of the occurrence of a fault current in an electrical conductor within the enclosure, said indicator system comprising, in combination:
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status indicating means including a non-magnetic test point member extending through an aperture in the enclosure so as to define a tamper-resistant magnetic test point contiguous with the exterior surface of the enclosure, and a core member of relatively high magnetic retention in magnetic communication with said test point member for establishing a magnetic field in said test point member; fault responsive circuit means within the enclosure responsive to the current level in the conductor and including a magnetic winding in magnetic communication with said core member for magnetizing said core member to provide the fault indicative magnetic field at said test point upon occurrence of a fault current in the conductor; and removable indicator means user-engagable to said magnetic test point and responsive to the fault indicative magnetic field for indicating to the user the status of the conductor. - View Dependent Claims (32, 33, 34)
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35. A removable circuit indicator for use in conjunction with a fault indicator of the type which includes a test point member forming a magnetic test point on the exterior of an enclosure, the magnetic test point having a magnetic state of one polarity indicative of the occurrence of a fault current in the conductor, and a magnetic state of the opposite polarity indicative of a normal reset condition, said indicator comprising, in combination:
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a base member adapted for user-positioning in close proximity to said magnetic test point; a user-viewable flag member mounted on said base member for movement between a trip-indicating position and a reset indicating position; and means including a permanent magnet mounted for rotation with said flag member for positioning said flag member in said trip-indicating position in response to a magnetic state of said one polarity on said test point member, and in said reset-indicating position in response to a magnetic state of said opposite polarity on said test point member, when said base member is positioned to bring said flag member into magnetic communication with said magnetic test point. - View Dependent Claims (36, 37, 38, 39)
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40. A fault indicator for use in conjunction with a removable magnetically actuated circuit status indicator for providing on the exterior of an electrical equipment enclosure having an aperture a magnetic state for actuating the indicator following the occurrence of a fault current in an electrical conductor within the enclosure, said indicator comprising, in combination:
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a magnetic test point assembly including a hollow relatively non-magnetic test point member having a shank portion of relatively lesser diameter extending through the aperture, and a head portion of relatively larger diameter exposed on the exterior surface of the housing so as to form a tamper-resistant magnetic test point contiguous with the surface of the enclosure; means including a core member of relatively high magnetic retention capability disposed at least partially within said test point member for magnetizing said core member to a selected magnetic state; and fault detection circuit means within said enclosure responsive to the current level in the conductor and including a magnetic winding for conditioning said core member and said test point to a magnetic state of one magnetic polarity upon occurrence of a fault current in the conductor, and to a magnetic state of opposite magnetic polarity upon restoration of current through the conductor. - View Dependent Claims (41, 42)
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43. A fault indicator system for providing on the exterior of an electrical equipment enclosure having a test point aperture a magnetic state indicative of the occurrence of a fault current in an electrical conductor within the enclosure, said indicator system comprising, in combination:
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a magnetic test point assembly including a hollow relatively non-magnetic test point member having a shank portion of relatively lesser diameter extending through said aperture, and a head portion of relatively larger diameter exposed on the exterior surface of the housing so as to form a tamper-resistant magnetic test point contiguous with the surface of the enclosure; means including a core member of relatively high magnetic retention capability disposed at least partially within said head portion for providing a magnetic state at said magnetic test point; means including at least one magnetic winding at least partially disposed within said test point member for magnetizing said core portion to provide a selected magnetic state; fault detector circuit means within said enclosure responsive to the current level in the conductor and including said magnetic winding for magnetizing said core member to produce a magnetic state at said test point of one magnetic polarity upon occurrence of a fault current in the conductor, and a magnetic state of the opposite magnetic polarity upon restoration of current through the conductor; and a removable circuit status indicator tool engagable to said head portion and responsive to the magnetic field at said magnetic test point for visually indicating the status of the conductor. - View Dependent Claims (44, 45)
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46. A fault indicator for use in conjunction with a removable magnetically-actuated circuit status indicator for providing on the exterior surface of an electrical equipment enclosure a magnetic flux for actuating the indicator following the occurrence of a fault current in an electrical conductor within the enclosure, said indicator comprising, in combination:
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status indicating means comprising a magnetic circuit serially including a magnetizable core and a magnetic gap for producing at a test point on the exterior of the enclosure the magnetic flux; and fault responsive means for magnetizing said magnetic core upon the occurrence of a fault current to produce the magnetic flux at said test point.
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Specification