Current measuring and automatically resettable fault indicating means

Claim 2

An automatically resettable fault indicator for an alternating current conductor comprising: a demagnetizable magnetic core adapted to embrace said conductor and normally energized with unidirectional magnetic flux to provide a pair of opposite poles and adapted to be demagnetized in accordance with the magnitude of alternating current flow in said conductor, a stationary permanent magnet having its poles adjacent unlike poles of said magnetic core, a pivotable permanent magnet adjacent said stationary permanent magnet taking up a normal position when the magnetic field from said poles of said magnetic core is greater than the magnetic field from said poles of said permanent magnet, magnetizing winding means on said magnetic core insulated from and adapted to be capacitively coupled to said conductor, a counterpoise spaced from said conductor, switch means, a capacitor connected across said winding means through said switch means, and a pair of series connected rectifiers connected across said capacitor with the common connection therebetween connected to said counterpoise, said pivotable permanent magnet being shifted to an alternate position when the alternating current flow in said conductor exceeds a predetermined value and effects a corresponding reduction in said magnetic field from said poles of said magnetic core, energization of said conductor charging said capacitor, and closure of said switch means discharging said capacitor through said winding means to restore to normal said magnetic field from said poles of said magnetic core and effect movement of said pivotable permanent magnet to said normal position thereof.

Claim 3

The fault indicator according to claim 1 wherein said winding means comprises a pair of series connected windings arranged on said magnetic core in opposite winding directions to generate said opposite poles on flow therethrough of direct current.

Claim 4

The fault indicator according to claim 1 wherein said counterpoise is charged to one polarity during one half cycle of the flow of alternating current in said conductor and said capacitor is charged with the same polarity during the next half cycle of the fLow of alternating current in said conductor.

Claim 5

The fault indicator according to claim 1 wherein means responsive to the application of a predetermined charge on said capacitor effect closure of said switch means to discharge said capacitor as aforesaid.

Claim 6

The fault indicator according to claim 1 wherein said switch means includes an SCR, and a space discharge device responsive to the charge on said capacitor renders said SCR conducting when said charge reaches a predetermined value.

Claim 7

The fault indicator according to claim 1 wherein said magnetic core is in the form of a ring, said winding means comprises a pair of windings wound in opposite winding directions on said ring, and means connect said windings in series circuit relation.

Claim 8

The fault indicator according to claim 6 wherein said magnetic core is arranged to receive therethrough said alternating current carrying conductor.

Claim 9

An automatically resettable fault indicator for an alternating current conductor comprising: a demagnetizable bifurcated yoke of magnetic material for application to said conductor such that the arms thereof are normally energized with unidirectional magnetic flux to have opposite poles at the distal ends of said arms and are subjected to demagnetization in accordance with the magnitude of alternating current flow in said conductor, a stationary permanent magnet between the distal ends of said arms having its poles adjacent unlike poles thereof, a pivotable permanent magnet adjacent said stationary permanent magnet taking up a normal position when the magnetic field from said poles at said distal ends is greater than the magnetic field from said poles of said permanent magnet, a magnetizing winding surrounding each of said arms insulated from and adapted to be capacitively coupled to said conductor, a counterpoise spaced from said conductor, switch means, a capacitor connected across said windings through said switch means, and a pair of series connected rectifiers connected across said capacitor with the common connection therebetween connected to said counterpoise, said pivotable permanent magnet being shifted to an alternate position when the alternating current flow in said conductor exceeds a predetermined value and effects a corresponding reduction in said magnetic field from said poles at said distal ends, energization of said conductor charging said capacitor, and closure of said switch means discharging said capacitor through said windings to restore to normal said magnetic field from said distal ends and effect movement of said pivotable permanent magnet to said normal position thereof.

Claim 10

An automatically resettable fault indicator for an alternating current conductor comprising: a demagnetizable bifurcated yoke of magnetic material for application to said conductor such that the arms thereof are normally energized with unidirectional magnetic flux to have opposite poles at the distal ends of said arms and are subjected to demagnetization in accordance with the magnitude of alternating current flow in said conductor, a stationary permanent magnet between the distal ends of said arms having its poles adjacent unlike poles thereof, a pivotable permanent magnet adjacent said stationary permanent magnet taking up a normal position when the magnetic field from said poles at said distal ends is greater than the magnetic field from said poles of said permanent magnet, a magnetizing winding surrounding each of said arms insulated from and adapted to be capacitively coupled to said conductor, a counterpoise spaced from said conductor, switch means, a capacitor connected across said windings through said switch means, and a pair of series connected rectifiers connected across said capacitor with the common connection therebetween connected to said counterpoise, said pivotable permanent magnet being shifted to an alternate position when the alternating current flow in said conductor exceeds a predetermined value and effects a corresponding reduction in said magnetic field from said poles at said distal ends, energization of said conductor charging said capacitor, and closure of said switch means discharging said capacitor through said windings to restore to normal said magnetic field from said distal ends and effect movement of said pivotable permanent magnet to said normal position thereof.

Claim 11

The fault indicator according to claim 8 wherein means connect said magnetizing windings in series circuit relation.

Claim 12

The fault indicator according to claim 8 wherein said counterpoise is charged to one polarity during one half cycle of the flow of alternating current in said conductor and said capacitor is charged with the same polarity during the next half cycle of the flow of alternating current in said conductor.

Claim 13

The fault indicator according to claim 8 wherein means responsive to the application of a predetermined charge on said capacitor effect closure of said switch means to discharge said capacitor as aforesaid.

Claim 14

the fault indicator according to claim 8 wherein said switch means includes an SCR, and a space discharge device responsive to the charge on said capacitor renders said SCR conducting when said charge reaches a predetermined value.