CA1211004A - Fault indicator with push button reset - Google Patents
Fault indicator with push button resetInfo
- Publication number
- CA1211004A CA1211004A CA000438243A CA438243A CA1211004A CA 1211004 A CA1211004 A CA 1211004A CA 000438243 A CA000438243 A CA 000438243A CA 438243 A CA438243 A CA 438243A CA 1211004 A CA1211004 A CA 1211004A
- Authority
- CA
- Canada
- Prior art keywords
- indicator
- fault
- reset
- magnet
- magnetic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000004020 conductor Substances 0.000 claims abstract description 37
- 238000004891 communication Methods 0.000 claims abstract description 9
- 230000004907 flux Effects 0.000 claims description 6
- 239000000463 material Substances 0.000 claims description 3
- 230000000694 effects Effects 0.000 claims 4
- 230000003750 conditioning effect Effects 0.000 claims 2
- 238000006073 displacement reaction Methods 0.000 claims 2
- 230000007246 mechanism Effects 0.000 description 8
- 230000003993 interaction Effects 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 206010013710 Drug interaction Diseases 0.000 description 1
- 241001504505 Troglodytes troglodytes Species 0.000 description 1
- 230000001143 conditioned effect Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000000994 depressogenic effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000010338 mechanical breakdown Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 1
- 229920002554 vinyl polymer Polymers 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H71/00—Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
- H01H71/04—Means for indicating condition of the switching device
Abstract
FAULT INDICATOR WITH PUSH BUTTON RESET Edmund O. Schweitzer, Jr. Abstract of the Disclosure A fault indicator for indicating the occurrence of a fault current in an electrical conductor includes a rotatable indicator flag having fault-indicating and reset-indicating positions in response to applied magnetic fields. Upon occur-rence of a fault current the indicator flag is set to the fault-indicating position by a first magnetic field generated by cur-rent flow through the conductor. Upon termination of the fault current the flag indicator is manually reset to the reset-indi-cating position by a permanent magnet, which is user-displaceable from a magnetically shielded position within the indicator housing to a position in magnetic communication with the flag indicator.
Description
SPECIFICATION
Background of the Invention This invention relates generally to fault indicators, and more particularly to non-self resetting fault indicators which include user-actuable reset means, such as described in U.S. Patents 3,413,548 and 4,086,529 of the present inventor.
This invention constitutes an improvement in such fault India actors.
Fault indicators are generally installed on conductors in commercial electrical power distribution systems. In such distribution systems a short circuit, or fault, may develop, no suiting in loss of service to consumers. Following the occur-Jo fence of such a fault it is necessary that the fault be quickly located and repaired to enable service to be restored.
Fault indicators are typically installed on a conductor and are constructed in such a manner that when the current flowing through the conductor exceeds a predetermined level an indicator is tripped to a fault-indicating state to indicate that such ox-cessive current has occurred Fault indicators placed on con-doctors which do not experience a fault current remain in an untrapped or reset-indicating state. By systematically inspecting the fault indicators located at various points in the power disk tribution system, the fault can be quickly located and repaired.
Generally when a fault occurs within a power duster-button system a circuit breaker in the system trips, cutting off sly current to a portion ox the system. Since no current flows in affected conductors in the system, fault indicators for use in such systems are constructed in such a manner that an indict-lion of the excessive current flow remains following the occur-fence of the fault, even through the current immediately follow-in the fault may have dropped to zero. A fault indicator in such a condition is said to be in a "tripped" state, and is no longer able to indicate the occurrence of a subsequent fault current. In order to make the indicator operative once again, it is necessary that the indicator be reset to a "reset" state.
One form of prior manually-reset fault indicator, as described in U.S. Patent No. 3,413,548, utilized a rotatable mounted bi-stable indicator flag having reset-indicating and fault-indicating positions to visually indicate tripped and reset states. This fault indicator was reset by means of a reset tool having a permanent magnet which was positioned in close proximity to the fault indicator by a lineman to magnetically reposition the indicator flag to its reset position. This was often a gum-bersome process, in that it was necessary for the lineman to carry a special reset tool, and lo accurately position the tool relative to the indicator housing in an often dark and cramped environment. This was particularly disadvantageous where it was necessary to individually reset a large number of fault indicators, since the burden in the reset procedure was multiplied many I times over.
I
In another form of prior manually-reset fault India actors, as described in U.S. Patent 4,086,529 , the indicator ; flag was positioned to its fault indicating position by a pole piece magnetized by the fault current, and repositioned to its reset-indicating position by a reset tool having a magnetic winding which demagnetized the pole piece This also required accurate placement of the reset tool.
Another prior fault indicator utilized a spring-biased indicator flag which was mechanically latched upon reaching a fault-indicating position. Reset was accomplished by displacing the latch to allow the spring to return the indicator flag to its reset position.
Another prior fault indicator provided a permanent magnet externally mounted to the indicator housing which could be pivoted or otherwise positioned so as to interact with the indicator flag to reposition the indicator to its reset position.
The arrangement had the disadvantage of being bulky, expensive, and prone to mechanical breakdown.
Thus a need exists for a fault indicator having simple, reliable self-contained user-actuable reset means, which avoids the disadvantages of prior constructions.
Accordingly, it is an object of this invention to pro-vise a new and improved user-resettable fault indicator.
It is another object of the present invention to pro-vise a self-contained manually~resettable fault indicator which can be conveniently reset without the need for external reset tools.
Summary of the Invention A fault indicator for indicating the occurrence of a fault current in an electrical conductor includes indicator means responsive to a first applied magnetic field for indicating the occurrence of a fault current in the conductor t and respond size to a second applied magnetic field for indicating the pro-since of a reset condition in the conductor. Trip detection means in magnetic communication with the conductor apply a first magnetic yield to the indicator means to indicate a fault con-diction upon the occurrence of a fault current. User-actuable reset means including a permanent magnet apply a second magnetic field to the indicator means to condition the indicator to a reset state.
Brief Description of the Drawings The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with the further objects and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings, in the several figures of which like reference numerals identify like elements, and in which:
Figure l is a perspective view of a fault indicator I constructed in accordance with the invention installed on an 12~ 4 electrical conductor.
Figure 2 is an exploded perspective view of the fault indicator of Figure 1 showing the indicator flag assembly and push button reset components thereof.
Figure 3 is a cross-sectional view taken along line 3-3 of Figure 1 and showing the fault indicator clamped in place on the conductor.
Figure 4 is a cross-sectional view of the fault India actor taken generally along line 4-4 of Figure 3.
Figure 5 is an exploded perspective view showing the principal components of the indicator flag assembly of the fault indicator.
Figure 6 is a sectional view of the indicator flag assembly taken along line 6-6 of Figure 2.
Figure pa is a simplified diagrammatic representation of the principal components of the push button reset mechanism and indicator flag assembly in a fault-indicating condition.
Figure 7b is a diagrammatic representation similar to Figure pa showing the reset assembly actuated to reset the India actor flag assembly to a reset-indicating condition.
Figure 7c is a diagrammatic representation similar to Figure pa showing-the reset mechanism and indicator flag assembly in a reset-indicating condition.
Description of the Preferred Embodiment . . . _ .
Referring to the Figures, and particularly to Figure 1, 12~ 4 a manually reset fault indicator 10 is shown installed in an operating position along an electrical conductor 11. Conductor 11, which is of a conventional type suitable for the commercial distribution of electrical power, comprises a central metallic conducting element 12 surrounded by an insulating sheath 13.
The fault indicator 10 comprises a housing block 14 in which are mounted an indicator flag assembly 16, a magnetic pole piece 17, a pair of handling members 18, 19, and a push button reset mechanism 21. The indicator flag assembly 16, which is preferably of the type disclosed in U S. Patent No.
3,413,548, is responsive to the application of external magnetic fields. More specifically, and as described in the reference, indicator assembly 16 is a bi-stable device having a normal or "reset" position, and a fault or "tripped" condition. The reset condition is that which normally exists while the fault India actor is in operation on a properly operating power distribution circuit. In this condition the fault indicator is responsive to excess current in the conductor on which the fault indicator is placed. If the current in the conductor exceeds a predator-mined value, the flag indicator assembly is conditioned to the fault or tripped condition which results in a visual indication that-the fault current has occurred. -In Figure 1, the fault indicator is shown in such a tripped condition, as is indicated by the letter F being visible on the face of the flag indicator assembly.
-~21.~
The housing block 14 is provided with a notch on its rear surface into which is positioned the electrical conductor.
To provide a magnetic field indicative of the current in this conductor, the fault indicator 10 includes flux concentrating means in the form of the generally ring shaped magnetic pole piece 17 for the purpose of applying an externally induced mug-netic field to the flag indicator assembly 16. Magnetic pole piece 17 also serves as a clamp to hold the fault indicator in place on the conductor. Handling members 18 and 19 are connected to the pole piece and the housing block respectively and are de-signed to be engaged by a special live line tool (not shown) carried by the lineman installing the fault indicator. The live line tool, used in conjunction with handling members 18 and 19, ; enables the lineman to safely position the fault indicator on a live electrical conductor.
Referring to Figures 5 and 6, the flag indicator as-symbol comprises a generally cylindrical flag indicator housing 23 and a transparent face place 24 which together form a sealed enclosure. Within the enclosure are positioned an indicator flag 26, a magnetic armature 27, an annular magnet 28, a spring clamp washer 29, and a pivot shaft 30, all mounted for rotation along the axis of the housing. A stationary permanent magnet 31 is affixed to the outer rear surface of the indicator housing.
Both the stationary magnetic 31 and the rotatable magnet 28 are annular in form, and contain four magnetic poles as shown.
The rotatable magnet 28, the armature 27 and the spring clamp washer 29 are each fixedly attached to pivot shaft 30, which is received in bearing surfaces in housing sections 23 and 24 to provide for free rotation of the assembly. The India actor flag, armature, rotatable magnet and spring clamp washer rotate through an arc determined by a sector removed from the periphery of the indicator flag. At the limits of rotation, the edges 33 or 34 of the sector engage a mechanical stop in the form of a pin 36 in the indicator housing, which prevents further rotation.
The indicator flag is held in either of two positions through the interaction of the rotatable magnet with the stationary magnet. Specifically, the repulsive forces between the like poles of the two magnets provides sufficient bias or indexing torque to hold the indicator flag in either a fault-indicating position, wherein edge 34 abuts pin 36, as shown in Figure pa;
or in a reset-indicating position, wherein edge 33 abuts pin 36, as shown in Figure 7c. The indicator flag remains in one of the two positions until an external magnetic field applies sufficient torque on the magnetic armature to rotate the flag from one post-lion to the other.
Figure 4 shows the relative positioning of indicator ; flag assembly and the ends of the magnetic pole piece 17. As current flows in conductor 11, the resulting magnetic flux is I concentrated by means of the magnetic pole piece and caused to Jo I
appear across the ends 44 and 46 of the pole piece as shown in Figure I When the indicator flag assembly 16 is in its resew position, the axis of magnetic armature 27 is at an angle with respect to the field lines. Upon the occurrence of a fault current, the magnetic field strength appearing between the ends 44 and 46 of pole piece 17 produces a torque sufficient to over-come the bias force between magnets 28 and 31 and rotate the indicator flag from the reset indicating position to the fault-indicating position. Reference is made to prove identified U.S. Patent No. 3,413,548 fur a further explanation of indicator flag assembly 26.
. Figure 2 shows the relative positioning of the flag indicator assembly 26, and the push button reset mechanism 21.
The flag indicator assembly 26 is received in a cylindrical no-cuss 37 on the front surface (as viewed in Figure 2) of housing block 14~ The push button reset mechanism is received in a cylindrical recess 38 on the bottom face of the housing block includes, in accordance with the invention, a permanent reset magnet 40 arranged for user-selective magnetic communication with indicator flag assembly.
As shown in Figures 2 and 4, reset magnet 40 is arranged in axial alignment with a non-metallic actuator stem 41.
The combination of magnet and plunger is dimensioned so as to be slid ably received within a cylindrical magnetic shield 42 formed of a material having high magnetic conductivity such as Jo 12~ 4 soft iron. The protruding end of stem 41 is enclosed within a rubber boot 43 which serves to seal thy reset mechanism against dirt and moisture. By pressing the stem of the plunger extending through the bottom surface of the magnetic shield, the reset magnet is displaced relative to the shield along the axis of the plunger.
Figures pa, 7b and 7c illustrate the operation of push button reset mechanism 21. Figure pa shows indicator flag 26 in the tripped position and the push button reset mechanism in a non-actuated state. At this time magnetic shield 42 extends be-pond the top surface of reset magnet 40 and serves to shield magnetic armature 27 from the magnetic field produced by the reset magnet. Consequently, the torque produced by the inter-action of the field produced by the reset magnet and the magnetic armature 27 is insufficient to reposition the indicator to the reset position. ivory, when actuator stem 41 is depressed as shown in Figure 7b, the top surface of reset magnet 40 is moved beyond the end ox the magnetic shield and is brought into closer magnetic communication with magnetic armature 27. The resulting attractive force is of sufficient strength to overcome the in-dewing force produced by magnets 28 and 31 contained within the flag indicator assembly, causing indicator flag 26-to rotate in a counterclockwise direction as shown in Figure 7b until the indicator flag reaches the reset position, as shown in Figure 7c.
Once the flag indicator reaches the reset position, the 12~ 4 indexing force produced by magnets 28 and 31 in indicator flag assembly 16 serve to hold the indicator flag in the reset post-lion until the occurrence of the next fault condition. Wren actuator stem 41 is released, the interaction of reset magnet 40 with magnetic shield 42 results in a strong restoring force on the reset magnet-plunger combination which tends to restore the push button to its unrepressed state. Thus, the need for a restoring spring is avoided.
Figure 3 further illustrates the manner in which fault indicator 10 is mounted on conductor 11~ One end 44 of mug-netic pole piece 17 is permanently attached to housing block 14.
The other en 46 of the pole piece is removably received in a recess 47 of the housing block. The pole piece, which is come prosed of a plurality of flexible metallic strips 48 encased within an electric fly insulating sheath 49, is flexible, and can be configured from the open position shown by the dashed line in Figure 3 to the closed position shown by the solid lines in Figure 3. While the pole piece is in the open position, the vault indicator can be positioned on an electrical conductor.
The fault indicator can then be secured in place on the conductor by introducing the end 46 of the pole piece into recess 47 of the housing block. A coil spring 51 serves both to lock the fault indicator in position on the conductor and to bias end 46 into the recess 47. A length of rubber or vinyl tubing 52 may ~25 be positioned between the spring and the conductor to protect A
I
the insulation of the conductor from chafing.
While in this embodiment resetting is accomplished by linearly displacing a disc-shaped permanent magnet with respect to a cylindrical magnetic shield so as to apply a magnetic field to indicator flag assembly I it will be appreciated that such resetting may be accomplished through the use of magnets and shields of other shapes, sizes and movements. Furthermore, while in this embodiment the permanent magnet is displaced relative to the magnetic shield, resetting may also be accom-~10 polished through use of a system in which the magnet remains stationary and the magnetic shield is displaced to establish magnetic communication with the indicator flag assembly.
While a particular embodiment of the invention has been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made therein without departing from the invention in its broader aspects, and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention.
, . .
Background of the Invention This invention relates generally to fault indicators, and more particularly to non-self resetting fault indicators which include user-actuable reset means, such as described in U.S. Patents 3,413,548 and 4,086,529 of the present inventor.
This invention constitutes an improvement in such fault India actors.
Fault indicators are generally installed on conductors in commercial electrical power distribution systems. In such distribution systems a short circuit, or fault, may develop, no suiting in loss of service to consumers. Following the occur-Jo fence of such a fault it is necessary that the fault be quickly located and repaired to enable service to be restored.
Fault indicators are typically installed on a conductor and are constructed in such a manner that when the current flowing through the conductor exceeds a predetermined level an indicator is tripped to a fault-indicating state to indicate that such ox-cessive current has occurred Fault indicators placed on con-doctors which do not experience a fault current remain in an untrapped or reset-indicating state. By systematically inspecting the fault indicators located at various points in the power disk tribution system, the fault can be quickly located and repaired.
Generally when a fault occurs within a power duster-button system a circuit breaker in the system trips, cutting off sly current to a portion ox the system. Since no current flows in affected conductors in the system, fault indicators for use in such systems are constructed in such a manner that an indict-lion of the excessive current flow remains following the occur-fence of the fault, even through the current immediately follow-in the fault may have dropped to zero. A fault indicator in such a condition is said to be in a "tripped" state, and is no longer able to indicate the occurrence of a subsequent fault current. In order to make the indicator operative once again, it is necessary that the indicator be reset to a "reset" state.
One form of prior manually-reset fault indicator, as described in U.S. Patent No. 3,413,548, utilized a rotatable mounted bi-stable indicator flag having reset-indicating and fault-indicating positions to visually indicate tripped and reset states. This fault indicator was reset by means of a reset tool having a permanent magnet which was positioned in close proximity to the fault indicator by a lineman to magnetically reposition the indicator flag to its reset position. This was often a gum-bersome process, in that it was necessary for the lineman to carry a special reset tool, and lo accurately position the tool relative to the indicator housing in an often dark and cramped environment. This was particularly disadvantageous where it was necessary to individually reset a large number of fault indicators, since the burden in the reset procedure was multiplied many I times over.
I
In another form of prior manually-reset fault India actors, as described in U.S. Patent 4,086,529 , the indicator ; flag was positioned to its fault indicating position by a pole piece magnetized by the fault current, and repositioned to its reset-indicating position by a reset tool having a magnetic winding which demagnetized the pole piece This also required accurate placement of the reset tool.
Another prior fault indicator utilized a spring-biased indicator flag which was mechanically latched upon reaching a fault-indicating position. Reset was accomplished by displacing the latch to allow the spring to return the indicator flag to its reset position.
Another prior fault indicator provided a permanent magnet externally mounted to the indicator housing which could be pivoted or otherwise positioned so as to interact with the indicator flag to reposition the indicator to its reset position.
The arrangement had the disadvantage of being bulky, expensive, and prone to mechanical breakdown.
Thus a need exists for a fault indicator having simple, reliable self-contained user-actuable reset means, which avoids the disadvantages of prior constructions.
Accordingly, it is an object of this invention to pro-vise a new and improved user-resettable fault indicator.
It is another object of the present invention to pro-vise a self-contained manually~resettable fault indicator which can be conveniently reset without the need for external reset tools.
Summary of the Invention A fault indicator for indicating the occurrence of a fault current in an electrical conductor includes indicator means responsive to a first applied magnetic field for indicating the occurrence of a fault current in the conductor t and respond size to a second applied magnetic field for indicating the pro-since of a reset condition in the conductor. Trip detection means in magnetic communication with the conductor apply a first magnetic yield to the indicator means to indicate a fault con-diction upon the occurrence of a fault current. User-actuable reset means including a permanent magnet apply a second magnetic field to the indicator means to condition the indicator to a reset state.
Brief Description of the Drawings The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with the further objects and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings, in the several figures of which like reference numerals identify like elements, and in which:
Figure l is a perspective view of a fault indicator I constructed in accordance with the invention installed on an 12~ 4 electrical conductor.
Figure 2 is an exploded perspective view of the fault indicator of Figure 1 showing the indicator flag assembly and push button reset components thereof.
Figure 3 is a cross-sectional view taken along line 3-3 of Figure 1 and showing the fault indicator clamped in place on the conductor.
Figure 4 is a cross-sectional view of the fault India actor taken generally along line 4-4 of Figure 3.
Figure 5 is an exploded perspective view showing the principal components of the indicator flag assembly of the fault indicator.
Figure 6 is a sectional view of the indicator flag assembly taken along line 6-6 of Figure 2.
Figure pa is a simplified diagrammatic representation of the principal components of the push button reset mechanism and indicator flag assembly in a fault-indicating condition.
Figure 7b is a diagrammatic representation similar to Figure pa showing the reset assembly actuated to reset the India actor flag assembly to a reset-indicating condition.
Figure 7c is a diagrammatic representation similar to Figure pa showing-the reset mechanism and indicator flag assembly in a reset-indicating condition.
Description of the Preferred Embodiment . . . _ .
Referring to the Figures, and particularly to Figure 1, 12~ 4 a manually reset fault indicator 10 is shown installed in an operating position along an electrical conductor 11. Conductor 11, which is of a conventional type suitable for the commercial distribution of electrical power, comprises a central metallic conducting element 12 surrounded by an insulating sheath 13.
The fault indicator 10 comprises a housing block 14 in which are mounted an indicator flag assembly 16, a magnetic pole piece 17, a pair of handling members 18, 19, and a push button reset mechanism 21. The indicator flag assembly 16, which is preferably of the type disclosed in U S. Patent No.
3,413,548, is responsive to the application of external magnetic fields. More specifically, and as described in the reference, indicator assembly 16 is a bi-stable device having a normal or "reset" position, and a fault or "tripped" condition. The reset condition is that which normally exists while the fault India actor is in operation on a properly operating power distribution circuit. In this condition the fault indicator is responsive to excess current in the conductor on which the fault indicator is placed. If the current in the conductor exceeds a predator-mined value, the flag indicator assembly is conditioned to the fault or tripped condition which results in a visual indication that-the fault current has occurred. -In Figure 1, the fault indicator is shown in such a tripped condition, as is indicated by the letter F being visible on the face of the flag indicator assembly.
-~21.~
The housing block 14 is provided with a notch on its rear surface into which is positioned the electrical conductor.
To provide a magnetic field indicative of the current in this conductor, the fault indicator 10 includes flux concentrating means in the form of the generally ring shaped magnetic pole piece 17 for the purpose of applying an externally induced mug-netic field to the flag indicator assembly 16. Magnetic pole piece 17 also serves as a clamp to hold the fault indicator in place on the conductor. Handling members 18 and 19 are connected to the pole piece and the housing block respectively and are de-signed to be engaged by a special live line tool (not shown) carried by the lineman installing the fault indicator. The live line tool, used in conjunction with handling members 18 and 19, ; enables the lineman to safely position the fault indicator on a live electrical conductor.
Referring to Figures 5 and 6, the flag indicator as-symbol comprises a generally cylindrical flag indicator housing 23 and a transparent face place 24 which together form a sealed enclosure. Within the enclosure are positioned an indicator flag 26, a magnetic armature 27, an annular magnet 28, a spring clamp washer 29, and a pivot shaft 30, all mounted for rotation along the axis of the housing. A stationary permanent magnet 31 is affixed to the outer rear surface of the indicator housing.
Both the stationary magnetic 31 and the rotatable magnet 28 are annular in form, and contain four magnetic poles as shown.
The rotatable magnet 28, the armature 27 and the spring clamp washer 29 are each fixedly attached to pivot shaft 30, which is received in bearing surfaces in housing sections 23 and 24 to provide for free rotation of the assembly. The India actor flag, armature, rotatable magnet and spring clamp washer rotate through an arc determined by a sector removed from the periphery of the indicator flag. At the limits of rotation, the edges 33 or 34 of the sector engage a mechanical stop in the form of a pin 36 in the indicator housing, which prevents further rotation.
The indicator flag is held in either of two positions through the interaction of the rotatable magnet with the stationary magnet. Specifically, the repulsive forces between the like poles of the two magnets provides sufficient bias or indexing torque to hold the indicator flag in either a fault-indicating position, wherein edge 34 abuts pin 36, as shown in Figure pa;
or in a reset-indicating position, wherein edge 33 abuts pin 36, as shown in Figure 7c. The indicator flag remains in one of the two positions until an external magnetic field applies sufficient torque on the magnetic armature to rotate the flag from one post-lion to the other.
Figure 4 shows the relative positioning of indicator ; flag assembly and the ends of the magnetic pole piece 17. As current flows in conductor 11, the resulting magnetic flux is I concentrated by means of the magnetic pole piece and caused to Jo I
appear across the ends 44 and 46 of the pole piece as shown in Figure I When the indicator flag assembly 16 is in its resew position, the axis of magnetic armature 27 is at an angle with respect to the field lines. Upon the occurrence of a fault current, the magnetic field strength appearing between the ends 44 and 46 of pole piece 17 produces a torque sufficient to over-come the bias force between magnets 28 and 31 and rotate the indicator flag from the reset indicating position to the fault-indicating position. Reference is made to prove identified U.S. Patent No. 3,413,548 fur a further explanation of indicator flag assembly 26.
. Figure 2 shows the relative positioning of the flag indicator assembly 26, and the push button reset mechanism 21.
The flag indicator assembly 26 is received in a cylindrical no-cuss 37 on the front surface (as viewed in Figure 2) of housing block 14~ The push button reset mechanism is received in a cylindrical recess 38 on the bottom face of the housing block includes, in accordance with the invention, a permanent reset magnet 40 arranged for user-selective magnetic communication with indicator flag assembly.
As shown in Figures 2 and 4, reset magnet 40 is arranged in axial alignment with a non-metallic actuator stem 41.
The combination of magnet and plunger is dimensioned so as to be slid ably received within a cylindrical magnetic shield 42 formed of a material having high magnetic conductivity such as Jo 12~ 4 soft iron. The protruding end of stem 41 is enclosed within a rubber boot 43 which serves to seal thy reset mechanism against dirt and moisture. By pressing the stem of the plunger extending through the bottom surface of the magnetic shield, the reset magnet is displaced relative to the shield along the axis of the plunger.
Figures pa, 7b and 7c illustrate the operation of push button reset mechanism 21. Figure pa shows indicator flag 26 in the tripped position and the push button reset mechanism in a non-actuated state. At this time magnetic shield 42 extends be-pond the top surface of reset magnet 40 and serves to shield magnetic armature 27 from the magnetic field produced by the reset magnet. Consequently, the torque produced by the inter-action of the field produced by the reset magnet and the magnetic armature 27 is insufficient to reposition the indicator to the reset position. ivory, when actuator stem 41 is depressed as shown in Figure 7b, the top surface of reset magnet 40 is moved beyond the end ox the magnetic shield and is brought into closer magnetic communication with magnetic armature 27. The resulting attractive force is of sufficient strength to overcome the in-dewing force produced by magnets 28 and 31 contained within the flag indicator assembly, causing indicator flag 26-to rotate in a counterclockwise direction as shown in Figure 7b until the indicator flag reaches the reset position, as shown in Figure 7c.
Once the flag indicator reaches the reset position, the 12~ 4 indexing force produced by magnets 28 and 31 in indicator flag assembly 16 serve to hold the indicator flag in the reset post-lion until the occurrence of the next fault condition. Wren actuator stem 41 is released, the interaction of reset magnet 40 with magnetic shield 42 results in a strong restoring force on the reset magnet-plunger combination which tends to restore the push button to its unrepressed state. Thus, the need for a restoring spring is avoided.
Figure 3 further illustrates the manner in which fault indicator 10 is mounted on conductor 11~ One end 44 of mug-netic pole piece 17 is permanently attached to housing block 14.
The other en 46 of the pole piece is removably received in a recess 47 of the housing block. The pole piece, which is come prosed of a plurality of flexible metallic strips 48 encased within an electric fly insulating sheath 49, is flexible, and can be configured from the open position shown by the dashed line in Figure 3 to the closed position shown by the solid lines in Figure 3. While the pole piece is in the open position, the vault indicator can be positioned on an electrical conductor.
The fault indicator can then be secured in place on the conductor by introducing the end 46 of the pole piece into recess 47 of the housing block. A coil spring 51 serves both to lock the fault indicator in position on the conductor and to bias end 46 into the recess 47. A length of rubber or vinyl tubing 52 may ~25 be positioned between the spring and the conductor to protect A
I
the insulation of the conductor from chafing.
While in this embodiment resetting is accomplished by linearly displacing a disc-shaped permanent magnet with respect to a cylindrical magnetic shield so as to apply a magnetic field to indicator flag assembly I it will be appreciated that such resetting may be accomplished through the use of magnets and shields of other shapes, sizes and movements. Furthermore, while in this embodiment the permanent magnet is displaced relative to the magnetic shield, resetting may also be accom-~10 polished through use of a system in which the magnet remains stationary and the magnetic shield is displaced to establish magnetic communication with the indicator flag assembly.
While a particular embodiment of the invention has been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made therein without departing from the invention in its broader aspects, and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention.
, . .
Claims (23)
1. A fault indicator for indicating the occurrence of a fault current in an electrical conductor, comprising a housing;
indicator means in said housing having fault and reset indicating states in response to an applied magnetic field for indicating the occurrence of fault and reset conditions in the conductor;
flux concentrating means in magnetic communication with said conductor for applying a first magnetic field to said indicator means to condition said indicator means to a fault state upon the occurrence of a fault current in the conductor; and user-actuable reset means including a permanent reset magnet mounted for reciprocation within said housing for applying a second magnetic field to said indicator means upon reciprocation of said permanent magnet to condition said indicator means to a reset state.
indicator means in said housing having fault and reset indicating states in response to an applied magnetic field for indicating the occurrence of fault and reset conditions in the conductor;
flux concentrating means in magnetic communication with said conductor for applying a first magnetic field to said indicator means to condition said indicator means to a fault state upon the occurrence of a fault current in the conductor; and user-actuable reset means including a permanent reset magnet mounted for reciprocation within said housing for applying a second magnetic field to said indicator means upon reciprocation of said permanent magnet to condition said indicator means to a reset state.
2. A fault indicator as defined in claim 1 wherein said first magnetic field provides a first force effect in one direction on said indicator means and said second magnetic field provides a second force effect of different direction on said indicator means.
3. A fault indicator as defined in claim 1 wherein said reset means include magnetic shield means within said housing for confining the field of said magnet, and displacement means for mechanically separating said reset magnet and said shield means whereby said second magnetic field is applied to said indicator means to condition said indicator means to a reset state.
4. A fault indicator as defined in claim 3 wherein said magnetic shield is affixed to said housing and said magnet is movable.
5. A fault indicator as defined in claim 4 wherein said magnetic shield comprises a sleeve formed of a material having high magnetic conductivity, and said permanent magnet is mounted for reciprocation within said sleeve.
6. A fault indicator as defined in claim 5 wherein said magnet comprises a cylindrical form having an outside dia-meter corresponding to the inside diameter of said sleeve.
7. A fault indicator as defined in claim 4 including an actuator stem operatively engaging said magnet for moving said magnet along the axis of the sleeve.
8. A fault indicator as defined in claim 7 including a boot over the end of said actuator stem.
9. A fault indicator as defined in claim 4 in which the sleeve is received within an appropriately dimensioned bore within said housing.
10. A fault indicator as defined in claim 1 wherein said indicator means comprise a rotatable mounted indicator flag and an indexing magnet, and armature means rotatably coupled to said indicator flag and responsive to said first and second applied magnetic fields for positioning said indicator flag in said trip and reset states.
11. A fault indicator as defined in claim 10 further comprising magnet indexing means including a first permanent magnet mounted for rotation with said indicator flag and a second permanent member fixedly positioned relative to said housing for indexing said indicator flag alternatively in said trip and reset states.
12. A fault indicator as defined in claim 1 wherein said flux concentrating means comprise a magnetic pole piece mounted to said housing and at least partially encircling the conductor and having magnetic poles in magnetic communication with said indicator means for conditioning said indicator means to said trip condition.
13. A fault indicator as defined in claim 5 wherein said magnet has a non-actuated position within said sleeve.
14. A fault indicator for indicating the occurrence of a fault current in a conductor comprising:
a housing;
indicator means in said housing responsive to a first applied magnetic field providing a first force effect of one direction for indicating the occurrence of a fault current in the conductor and responsive to a second applied magnetic field providing a second force effect of a different direction for indicating the presence of a reset condition in the conductor;
flux concentrating means in magnetic communication with said conductor for applying said first magnetic field to said indicator means upon occurrence of the fault current; and user-actuable reset means including a permanent mag-net within said housing for applying said second magnetic field to said indicator means to condition said indicator means to a reset state, magnetic shield means within said housing for con-fining the field of said magnet, and displacement means for mech-anically separating said magnet and said shield means whereby said second magnetic field is applied to said indicator-means to condition said indicator means to a reset state.
a housing;
indicator means in said housing responsive to a first applied magnetic field providing a first force effect of one direction for indicating the occurrence of a fault current in the conductor and responsive to a second applied magnetic field providing a second force effect of a different direction for indicating the presence of a reset condition in the conductor;
flux concentrating means in magnetic communication with said conductor for applying said first magnetic field to said indicator means upon occurrence of the fault current; and user-actuable reset means including a permanent mag-net within said housing for applying said second magnetic field to said indicator means to condition said indicator means to a reset state, magnetic shield means within said housing for con-fining the field of said magnet, and displacement means for mech-anically separating said magnet and said shield means whereby said second magnetic field is applied to said indicator-means to condition said indicator means to a reset state.
15. A fault indicator as defined in claim 14 wherein said magnetic shield is affixed to said housing and said magnet is movable.
16. A fault indicator as defined in claim 15 wherein said magnetic shield comprises a sleeve formed of a material having high magnetic conductivity, and said permanent magnet is mounted for reciprocation within said sleeve.
17. A fault indicator as defined in claim 16 wherein said magnet comprises a cylindrical form having an outside dia-meter corresponding to the inside diameter of said sleeve.
18. A fault indicator as defined in claim 17 including an actuator stem operatively engaging said magnet for moving said magnet along the axis of the sleeve.
19. A fault indicator as defined in claim 18 including a boot over the end of said actuator.
20. A fault indicator as defined in claim 19 in which the sleeve is received within an appropriately dimensioned bore within said housing.
21. A fault indicator as defined in claim 14 wherein indicator means comprise a rotatable mounted indicator flag, and an indexing magnet and armature means rotatable coupled to said indicator flag and responsive to said first and second applied magnetic fields for positioning said indicator flag in said trip and reset states.
22. A fault indicator as defined in claim 21 which further comprises magnetic indexing means including a first permanent magnet mounted for rotation with said indicator flag and a second permanent magnet fixedly positioned relative to said housing for indexing said indicator flag alternatively in said trip and reset states.
23. A fault indicator as defined in claim 14 wherein flux concentrating means comprise a magnetic pole piece mounted to said housing and at least partially encircling the conductor and having magnetic poles in magnetic communication with said indicator means for conditioning said indicator means to said trip condition.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/474,132 US4536758A (en) | 1983-03-10 | 1983-03-10 | Fault indicator with push button reset |
| US474,132 | 1983-03-10 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1211004A true CA1211004A (en) | 1986-09-09 |
Family
ID=23882310
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000438243A Expired CA1211004A (en) | 1983-03-10 | 1983-10-03 | Fault indicator with push button reset |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US4536758A (en) |
| CA (1) | CA1211004A (en) |
Families Citing this family (25)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4739326A (en) * | 1983-12-27 | 1988-04-19 | General Electric Company | Fault flag driver |
| US4862754A (en) * | 1987-12-11 | 1989-09-05 | Precision General, Inc. | Portable piston style sample cylinder |
| US4837552A (en) * | 1988-03-25 | 1989-06-06 | Allied-Signal Inc. | Non-volatile fault display with magnetic reset switch for adaptive braking system |
| US4930361A (en) * | 1988-12-29 | 1990-06-05 | Precision General, Inc. | Portable piston style sample cylinder |
| US5271353A (en) * | 1991-02-06 | 1993-12-21 | Gerard Besthorne | Medicine minder |
| ES2103122T3 (en) * | 1993-01-19 | 1997-08-16 | Hydro Quebec | CURRENT CURRENT IMPULSE INDICATOR. |
| DE4416008B4 (en) * | 1994-05-06 | 2005-02-10 | Knorr-Bremse Systeme für Nutzfahrzeuge GmbH | Vehicle equipped with a control system |
| EP0720023B1 (en) * | 1994-12-30 | 2003-05-07 | STMicroelectronics S.r.l. | Test method for power integrated devices |
| US5768760A (en) * | 1995-10-31 | 1998-06-23 | Nynex Science & Technology, Inc. | System and method for automatically processing coin collection boxes |
| US5889399A (en) * | 1997-02-06 | 1999-03-30 | Schweitzer, Jr.; Edmund O. | Test-point mounted fault indicator having immunity to fault currents in adjacent conductors |
| US5821869A (en) * | 1997-02-06 | 1998-10-13 | Schweitzer, Jr.; Edmund O. | Fault indicator for use with load-break connector |
| USD427921S (en) * | 1998-08-14 | 2000-07-11 | Dipl.-Ing H. Horstmann Gmbh | Rate adjustable faulted circuit indicator |
| WO2007137188A2 (en) * | 2006-05-19 | 2007-11-29 | Schweitzer Engineering Laboratories, Inc. | An article and method for providing a seal for an encapsulated device |
| US7692538B2 (en) * | 2006-05-19 | 2010-04-06 | Schweitzer Engineering Laboratories, Inc. | User interface for monitoring a plurality of faulted circuit indicators |
| MX2008014645A (en) | 2006-05-19 | 2008-11-28 | Schweitzer Engineering Lab Inc | User interface for monitoring a plurality of faulted circuit indicators. |
| NZ585731A (en) * | 2006-05-19 | 2012-02-24 | Schweitzer Engineering Lab Inc | Modifying memory locations within a power system device or fault indicator |
| WO2007137192A2 (en) | 2006-05-19 | 2007-11-29 | Schweitzer Engineering Laboratories, Inc. | Apparatus and system for adjusting settings of a power system device using a magnetically coupled actuator |
| WO2008066951A2 (en) * | 2006-05-19 | 2008-06-05 | Schweitzer Engineering Laboratories, Inc. | System and apparatus for optical communications through a semi-opaque material |
| US8059006B2 (en) | 2007-05-18 | 2011-11-15 | Schweitzer Engineering Laboratories, Inc. | System and method for communicating power system information through a radio frequency device |
| US8004377B2 (en) * | 2008-05-08 | 2011-08-23 | Cooper Technologies Company | Indicator for a fault interrupter and load break switch |
| US8665102B2 (en) * | 2008-07-18 | 2014-03-04 | Schweitzer Engineering Laboratories Inc | Transceiver interface for power system monitoring |
| US8526156B2 (en) | 2011-12-21 | 2013-09-03 | Schweitzer Engineering Laboratories Inc | High speed signaling of power system conditions |
| US9111696B1 (en) * | 2014-07-21 | 2015-08-18 | Eaton Corporation | Electrical switching apparatus, and trip unit and interface assembly therefor |
| ITUA20164207A1 (en) * | 2016-06-08 | 2017-12-08 | Gewiss Spa | COMPACT CONTROL MODULE, FOR AUTOMATIC RESET DEVICES |
| US11397198B2 (en) | 2019-08-23 | 2022-07-26 | Schweitzer Engineering Laboratories, Inc. | Wireless current sensor |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3413548A (en) * | 1964-10-05 | 1968-11-26 | Edmund O. Schweitzer Jr. | Electric current responsive means including a portable magnet indicator |
| US3996881A (en) * | 1975-09-11 | 1976-12-14 | Qualitrol Corporation | Rotary indicating instrument with magnetic reset |
| US4375617A (en) * | 1980-03-20 | 1983-03-01 | Schweitzer Edmund O Jun | Fault indicator with flux concentrating means |
-
1983
- 1983-03-10 US US06/474,132 patent/US4536758A/en not_active Expired - Lifetime
- 1983-10-03 CA CA000438243A patent/CA1211004A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| US4536758A (en) | 1985-08-20 |
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| Date | Code | Title | Description |
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| MKEX | Expiry | ||
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