US2939931A - Circuit breaker - Google Patents

Circuit breaker Download PDF

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US2939931A
US2939931A US629606A US62960656A US2939931A US 2939931 A US2939931 A US 2939931A US 629606 A US629606 A US 629606A US 62960656 A US62960656 A US 62960656A US 2939931 A US2939931 A US 2939931A
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magnet yoke
magnet
yoke
armature
coil
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US629606A
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Jr Joseph D Findley
Roswell C Van Sickle
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CBS Corp
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Westinghouse Electric Corp
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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01HELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H71/00Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
    • H01H71/10Operating or release mechanisms
    • H01H71/12Automatic release mechanisms with or without manual release
    • H01H71/24Electromagnetic mechanisms
    • H01H71/2454Electromagnetic mechanisms characterised by the magnetic circuit or active magnetic elements
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01HELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H71/00Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
    • H01H71/10Operating or release mechanisms
    • H01H71/12Automatic release mechanisms with or without manual release
    • H01H71/24Electromagnetic mechanisms
    • H01H71/2472Electromagnetic mechanisms with rotatable armatures

Definitions

  • This invention relates to circuit breakers and more particularly to high-speed electromagnet tripping devices for circuit breakers.
  • the fastest possible build-up of useful pull in the magnet is desired.
  • the initial rate of build-up of current and also pull is limited by the inductance of the coil.
  • the inductance of the coil is determined by the total llux linkages with the turns of the coil. Some of the flux linkages are caused by useful ilux crossing the working air gap of the magnet and threading the coil. The inductance ⁇ due to the useful flux cannot be avoided if the magnet is to do useful work.
  • leakage flux does not contribute to the magnetic pull, but does cause inductance and thus reduces the rate of build-up of current and, therefore, of the magnet pull. It has been found that this leakage llux may be temporarily suppressed or delayed by placing a conductor of good conductivity, such, for instance, as copper in the path of the leakage ilux. Eddy currents in the copper retard the build-up of the leakage ilux and effectively reduce the inductanceof the coil during the tripping period.
  • It is an object of the invention to provide a circuit breaker with an improved high-speed tripping electromagnet embodying novel shielding means for reducing the leakage flux to thereby reduce the inductance of the magnet coil during the working period.
  • Another object of the invention is to provide a circuit breaker with an improved high-speed tripping electromagnet having a fixed magnet yoke and an energizing coil Iembodying members of high conductivity disposed adjacent a considerable portion of the magnet yoke to reduce the inductance of the -magnet and increase the rate of rise of useful ux in the air gap.
  • Another object of the invention is to provide a circuit lbreaker with an improved high-speed tripping electromagnet comprising a iixed magnet yoke and an energizing coil having shielding means of high conductivity disposed about the magnet yoke to reduce the leakage tlux to" thereby decrease ⁇ the tripping time of the magnet.
  • Fig. .1 is a vertical sectional view showing a circuit breaker operating mechanism embodying the principles "Fig l;
  • Fig. 3 is an elevational view of the tripping electrolwhich has been contemplated, of applying that principle.
  • ICC Fig. 4 is a front elevational view of the tripping mechanism
  • Fig. 5 is a sectional view through the tripping electro- J magnet taken on line V-V of Fig. 3;
  • Fig. 6 is an exploded view of the tripping electromagnet.
  • circuit breaker is of the type disclosed in the patent to Joseph D. Findley, Jr., Patent No. 2,866,031 entitled Circuit Breaker, and assigned to the assignee of the instant invention.
  • the circuit breaker comprises generally a plurality of sets of separable contacts (not shown), an operating mechanism indicated generally at 23, a trip device indicated generally at 25 and a closing solenoid indicated generally at 27.
  • the moving contact structure for each pole of the breaker is connected by means of an operating rod 45 and nuts 49 to a cross bar 51 which is common to all polesof the breaker.
  • the cross bar 51 is pivotally connected at its ends by pivot pins 53 (only one being shown) to an operating bell crank lever 55 which is pivotally mounted on a shaft 57 supported in the spaced side members 59 (only one being shown) of a generally U- shaped frame 61.
  • the frame 61 is rigidly supported in the breaker frame structure (not shown) by means of a cross member 13 and a plate 62.
  • the operating mechanism consists of a closing lever 63 pivotally mounted on a shaft 65 supported in the side members 59 of the frame 61.
  • the closing lever 63 is operatively connected by means of a link 67, to the moving armature 69 of the closing solenoid 27.
  • the link 67 is connected by means of a pin 70 to the armature 69.
  • operating lever 55 and the closing lever 63 are connected by means of an underset toggle comprising toggle links 73 and.75 which are pivotally connected :together by a knee pivot pin 77.
  • the toggle link 73 is pivotally connected by a pin 79 to one arm of the operating bell crank lever 55 and the toggle link is pivotally connected to the closing lever 63 by a pin 81 which also connects the link 67 to the closing lever.
  • the closing lever 63 is held in the closed position by a spring biased latch 83 which normally engages a roller 85 on the pin 81.
  • the toggle 73, 75 is releasably held in a slightly underset position, in order to hold the breaker closed, by a latch member 87 which is pivoted on the shaft 65.
  • a link -89 connects the knee 77 of the toggle 73, 75 to the latch member 87 being pivotally connected to the latter by a pin 91.
  • the latch member 87 is normally releasably held in latching orvholding positions by a balanced trigger latch 99 which is actuated to unlatching positions byA operations of the trip device 25.
  • a latch roller 93 rotatably mounted on the latch member 87 by a pin 95, normally engages' the inner end 97 of the trigger latch 99 which is mounted for horizontal ⁇ movement by pivot means 101 supported on a cross bar 103 which is, in turn, mounted on the cross member 13 by means of bolts 105, and by a bracket 107 secured to the under side of the cross bar y103.
  • the electromagnetic trip device 25 is supported on a front plate 109 secured to the cross bar 103 and toV a cross member 15 by means of screws 111.
  • the trip device comprises a fixed E-shaped laminated magnet yoke 113 (Figs. 3, 4, 5 and 6) rigidly supported between a top plate 115 and a bottom plate 117, both made "of a plates 1'1'5 and 117.
  • An energizing coil 126 surrounds I the center lleg of -the xed magnet yoke )113.
  • a movable armature 1'27 is rigidlyfsecured to the lower end of a U-shapedarmature lever 1,29 (Figs.
  • the latch 99 Aisbiased byaspring 137 against anaadjustablefstop 1-39 y(Fig. 2') supported-on an upwardly extending Vportion 1410i the bracket 133 securedbyscrews L143 to the frontplate 109.
  • YAn'irnportant feature of the invention is the construction and arrangement of the tripping electromagnet whereby the? leakage ux is reduced which reduces the inductance of the energizing coil and increases Vtheinitial ⁇ rate of rise of ilux across the'working air gap and with it, the rate of build-up of the pull of the magnet. It has been found that by placing pieces of a material of high conductivity/,'such, forY instance, as copper in the pathofunusable leakage flux, the eddy currents in the conductive material retard the build-up of the leakage uiilr vandfelectively reduce the initial inductance of thel co Referring to Figs.
  • the electromagnet comprises, zas :previously :.described, the fixed .iE-shapedv magnet yoke..1.13 .rigidly held .between the upper-,and lower .platesll andzlll :respectively by ,thebolts 119.
  • the magnet yoke i113 are disposed ...U ,shaped-.pieces -ofv insulation 15.5.
  • a .UsshapedstriplSTpf insulation surrounds .three4 edges ing material is disposed around the insulating strip 157 and ⁇ between the latter andthe bolts 11-9 as clearly-seen in Figs. 3 and 5.
  • Strips l161 of conducting material disposed one on each side of the coil 126 between the coil and the outer legs of the magnet yoke, have their inner ends formed at right angles toward each other between the inner end of the coil and 'the magnetr yoke. Insulat ing strips 163 of .the-sameshape as 4the conducting strips 161 are disposed between the latter and the outer legs 'ofthemagnet yoke.
  • the 'facing sides of thelplates 115-and 117 are recessed as 4at v*165 to receive the coilV 126 and the spool -1767 yon which it is wound.
  • Spacers 169 of lconducting-material are placed in .the grooves 165 betweenthe inner end of the coil 1'26 and outer end of the plates 115 and 117, and are held in-placeby"one of the"bolts"1'19 which passes through openings in the plates and 117 and in the spacers 169.
  • the yfast ⁇ interrupting time provided by the invention will'effect considerable'reduction in wire damage in clearing faults on overhead lines, thereby permitting improved continuity of 'service and reduceline maintenance.
  • An electromagnetic trip Vdevice'ior a circuit breaker comprising a magnet yoke, a pair ofspacedfrigid members of highly conductive material disposed on opposite sides of said magnet yoke, energizing means on said magnet ⁇ yoke, and a plurality of conducting'members of highly conductive material disposedadjacent the edge portions of said magnet'yoke to vreduce-'the leakage-'tink of said magnet yoke and thereby increase the rate rof build-up of useful tlux.
  • An electromagnetic trip device for a circuit breaker comprising a laminated magnet yoke, *a* pair of spaced rigid members of 'a highly ⁇ conductive -material between which said laminated magnet yoke is disposed, a U-shaped strip otra highly conducting material disposed adjacent three edges of said laminated 4magnet yoke to reduce the leakage ux of said magnet yoke.
  • An electromagnetic trip device'for -a circuit-breaker comprising a magnet yoke, a pair of'rigidV members of highly conductive-material supporting said 'magnetyokc between them, members of insulating material disposed Vbetween said rigid members and-said magnet yoke, 1a
  • An electromagnetic trip device for a circuit breaker comprising a laminated E-shaped magnet yoke, a pair of relatively thick plates of a highly conductive material disposed one on each side of said magnet yoke, an energizing coil mounted on one of the legs of said E-shaped magnet yoke, and conducting strips of a highly conductive material disposed adjacent portions of the edges of said laminated magnet yoke, said plates and said conducting strips reducing the leakage llux of said magnet yoke.
  • An electroresponsive device comprising a rectangular E-shaped magnet yoke, a pair of plates of a highly conductive material disposed on opposite sides of said magnet yoke, said plates being larger than said magnet yoke, securing means securing said plates together to support said magnet yoke, an energizing coil mounted on the center leg of said magnet yoke, said plates being recessed to receive said energizing coil,-and a U-shaped conducting strip of a highly conductive material disposed around three sides of said magnet yoke between said magnet yoke and said securing means, said plates and said conducting strip reducing the leakage ilux of said magnet yoke.
  • An electroresponsive device comprising an' E-shaped laminated magnet yoke having three pole faces, a pair of plates of a highly conductive material disposed on opposite faces of said laminated magnet yoke and secured together to mount said magnet yoke, yan energizing coil surrounding the middle leg of said magnet yoke, a U-shaped conducting strip of a highly conductive material surrounding the edges of said magnet yoke except the pole faces, conducting strips of a highly conductive material disposed ⁇ between said coil and the inner edges of the outer legs of said magnet yoke, said plates and said conducting strips reducing the leakage ux of said magnet yoke.
  • An electroresponsive device comprising an E-shaped laminated magnet yoke having three pole faces, a pair of plates of a highly conductive material disposed on opposite faces of said laminated magnet yoke and secured together to mount said magnet yoke, members of insulating material between said plates and said magnet yoke, an energizing coil surrounding the middle leg of said magnet yoke, a U-shaped conducting strip of a highly conductive material surrounding the edges of said magnet yoke except the pole faces, conducting strips of a highly conductive material disposed between said coil and the inner edges of the outer legs of said magnet yoke, insulating means between each of said conducting strips and said magnet yoke, said plates and said conducting strips reducing the leakage llux of said magnet yoke.
  • a tractive electroresponsive device comprising a magnet yoke, a pair o-f members of a highly conductive non-magnetic material disposed on opposite sides of said magnet yoke, and means of a highly conductive nonmagnetic material disposed adjacent the edge portions of said magnet yoke, insulating means disposed between said highly conductive non-magnetic materials and said magnetic yoke, said insulating means being substantially thin to enable said highly conductive non-magnetic materials to be positioned in close enough proximity to said magnet yoke to effectively reduce the leakage flux and thereby increase the rate of build-up of useful ux.
  • a tractive electroresponsive device comprising a fixed magnet yoke and a movable armature, an energizing coil on said magnet yoke, 4and shielding means of a highly conductive non-magnetic material surrounding said magnet yoke except the portion adjacent said armature, said shielding means being in close enough proximity to said magnet yoke to effectively reduce the leakage flux in said magnet yoke to thereby increase the rate of buildup of useful flux.
  • a tractive electromagnetic device comprising a magnet yoke having a plurality of pole faces, a movable armature providing a plurality of air gaps, an energizing coil on said magnet yoke, a shield of a highly conductive material surrounding said electromagnet except the portion thereof adjacent said armature, said shield being disposed proximate to said magnet yoke to reduce the leakage flux in said magnet yoke to thereby increase the rate of build-up of useful flux across said air gaps, and portions of said shield extending adjacent the ends of said ⁇ armature to elfect a concentration of flux at said pole faces.
  • a tractive electromagnet comprising ⁇ a magnet yoke having a plurality of pole faces, a movable armature disposed adjacent said pole faces providing a plurality of air gaps, an energizing coil on said -magnet yoke, shielding means comprising a pair of members of a highly conductive material disposed at opposite sides of said magnet yoke, a shield of a highly conductive material surrounding the edges of said magnet yoke proximate thereto except the pole faces, said shielding means and said shield reducing the leakage ux to thereby increase the build-up of useful flux across said air gaps, and the end portions of said shield extending beyond said pole faces and adjacent the ends of said armature to effect concentration of flux at said pole faces.

Description

June 7, 1960 J. D. FINDLEY, JR., E rAL 2,939,931
CIRCUIT BREAKER Filed Dec. 20, 1956 2 Sheets-Sheet 1 Il"r |36 |00 O3 WI TNESSES INVENTORS i Joseph D. Findley,Jr. 8 6p Roswlrl C. Van Sickle.
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AfroRNEY June 7, 1960 J. D. FINDLEY, JR., ETAL 2,939,931
CIRCUIT BREAKER 2 Sheets-Sheet 2 Filed Dec. 20, 1956 Fig. 5.
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'P lOl --LQIH Insulation Insulation magnet and latching means;
United States Patent O CIRCUIT BREAKER Joseph I). Findley, Jr., Forest Hills, and Roswell C. Van Sickle, Wilkinsburg, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed Dec. 20, 1956, Ser. No. 629,606
12 Claims. (Cl. 20o- 104) This invention relates to circuit breakers and more particularly to high-speed electromagnet tripping devices for circuit breakers.
When a tractive electromagnet is used to trip a highspeed circuit breaker, the fastest possible build-up of useful pull in the magnet is desired. The initial rate of build-up of current and also pull is limited by the inductance of the coil. The inductance of the coil is determined by the total llux linkages with the turns of the coil. Some of the flux linkages are caused by useful ilux crossing the working air gap of the magnet and threading the coil. The inductance `due to the useful flux cannot be avoided if the magnet is to do useful work.
In most electromagnets there is a considerable portion of the total linx threading the coil or part of the coil which does not cross the working air gap. This socalled leakage flux does not contribute to the magnetic pull, but does cause inductance and thus reduces the rate of build-up of current and, therefore, of the magnet pull. It has been found that this leakage llux may be temporarily suppressed or delayed by placing a conductor of good conductivity, such, for instance, as copper in the path of the leakage ilux. Eddy currents in the copper retard the build-up of the leakage ilux and effectively reduce the inductanceof the coil during the tripping period.
=It is an object of the invention to provide a circuit breaker with an improved high-speed tripping electromagnet embodying novel shielding means for reducing the leakage flux to thereby reduce the inductance of the magnet coil during the working period.
Another object of the invention is to provide a circuit breaker with an improved high-speed tripping electromagnet having a fixed magnet yoke and an energizing coil Iembodying members of high conductivity disposed adjacent a considerable portion of the magnet yoke to reduce the inductance of the -magnet and increase the rate of rise of useful ux in the air gap.
Another object of the invention is to provide a circuit lbreaker with an improved high-speed tripping electromagnet comprising a iixed magnet yoke and an energizing coil having shielding means of high conductivity disposed about the magnet yoke to reduce the leakage tlux to" thereby decrease `the tripping time of the magnet.
`Other objects and advantages of the invention will be pointed out in the following description and illustrated in the accompanying drawings, which disclose, by way of example,.the principle of the invention and the best mode,
In said drawings: Fig. .1,is a vertical sectional view showing a circuit breaker operating mechanism embodying the principles "Fig l;
Fig. 3 is an elevational view of the tripping electrolwhich has been contemplated, of applying that principle.
2,939,931 Patented June 7, 1960 ICC Fig. 4 is a front elevational view of the tripping mechanism;
Fig. 5 is a sectional view through the tripping electro- J magnet taken on line V-V of Fig. 3; and
Fig. 6 is an exploded view of the tripping electromagnet.
The circuit breaker is of the type disclosed in the patent to Joseph D. Findley, Jr., Patent No. 2,866,031 entitled Circuit Breaker, and assigned to the assignee of the instant invention.
The circuit breaker comprises generally a plurality of sets of separable contacts (not shown), an operating mechanism indicated generally at 23, a trip device indicated generally at 25 and a closing solenoid indicated generally at 27.
The moving contact structure for each pole of the breaker is connected by means of an operating rod 45 and nuts 49 to a cross bar 51 which is common to all polesof the breaker. The cross bar 51 is pivotally connected at its ends by pivot pins 53 (only one being shown) to an operating bell crank lever 55 which is pivotally mounted on a shaft 57 supported in the spaced side members 59 (only one being shown) of a generally U- shaped frame 61. The frame 61 is rigidly supported in the breaker frame structure (not shown) by means of a cross member 13 and a plate 62.
In addition to the operating bell crank lever 55, the operating mechanism consists of a closing lever 63 pivotally mounted on a shaft 65 supported in the side members 59 of the frame 61. The closing lever 63 is operatively connected by means of a link 67, to the moving armature 69 of the closing solenoid 27. The link 67 is connected by means of a pin 70 to the armature 69. rIhe operating lever 55 and the closing lever 63 are connected by means of an underset toggle comprising toggle links 73 and.75 which are pivotally connected :together by a knee pivot pin 77. The toggle link 73 is pivotally connected by a pin 79 to one arm of the operating bell crank lever 55 and the toggle link is pivotally connected to the closing lever 63 by a pin 81 which also connects the link 67 to the closing lever. The closing lever 63 is held in the closed position by a spring biased latch 83 which normally engages a roller 85 on the pin 81.
The toggle 73, 75 is releasably held in a slightly underset position, in order to hold the breaker closed, by a latch member 87 which is pivoted on the shaft 65. A link -89 connects the knee 77 of the toggle 73, 75 to the latch member 87 being pivotally connected to the latter by a pin 91. The latch member 87 is normally releasably held in latching orvholding positions by a balanced trigger latch 99 which is actuated to unlatching positions byA operations of the trip device 25. A latch roller 93, rotatably mounted on the latch member 87 by a pin 95, normally engages' the inner end 97 of the trigger latch 99 which is mounted for horizontal `movement by pivot means 101 supported on a cross bar 103 which is, in turn, mounted on the cross member 13 by means of bolts 105, and by a bracket 107 secured to the under side of the cross bar y103.
The electromagnetic trip device 25 is supported on a front plate 109 secured to the cross bar 103 and toV a cross member 15 by means of screws 111. The trip device comprises a fixed E-shaped laminated magnet yoke 113 (Figs. 3, 4, 5 and 6) rigidly supported between a top plate 115 and a bottom plate 117, both made "of a plates 1'1'5 and 117. An energizing coil 126 surrounds I the center lleg of -the xed magnet yoke )113. A movable armature 1'27 is rigidlyfsecured to the lower end of a U-shapedarmature lever 1,29 (Figs. 1 and 4)- the spaced side Krnemberso'f which are lpivotally mounted 'on a Vpin 131 supported by andextending outwardly fromtheffront plate V109, the router VVend; ofrv the 'pin' 4131 b'eingsupported in a bracket 13-3 4'which Ais `lrigidly secured y'tothe "front plate 109. The lever 1A'1'29'is spaced from-the ffrontplate 109 by a spacer 134. A member 135, secured Vtothe upper-end of the Alever 129, carriesfan adjusting screw 136, Awhich isadapted, upon Yenergization of the l electromagnet, to engag'e'the' outer lenel 100-ofthe latch 99-to actuate the latch. The latch 99 Aisbiased byaspring 137 against anaadjustablefstop 1-39 y(Fig. 2') supported-on an upwardly extending Vportion 1410i the bracket 133 securedbyscrews L143 to the frontplate 109. A spring '145 (Figs. 1 `and 4), v'coiled `about `the pin 131, biases the armature member 135 against a stop -147 .which is also supportediby the portion 141 of 'the bracket 133.
When the electromagnet is energized in response to an overload current, it attracts the armature 127 and actuates the trigger latch 99 eecting release of the latch member 87. Upon release of the'latch member 87, the toggle "73, 75 limmediatelycollapses toward the left causing clockwise'rotation ofthe operating bell crank lever l55 andopening of the breaker. vThe collapse of the toggle 73 75 Acauses counterclockwise rotation-of the togglelink 75 `about the 4pin 81 during whichrotation a projection 149 on the toggle link 75 Iengages and moves the latch 83 toits unlatching position. As soon' as the latch 83 is'disengagedifrom'the'roller 85, a spring'1-51, connected under tension between the armature 69 vof the closing solenoid and the cross bar 103, moves the armature 69 toward the left to its unattracted position. This movement of the armature, through the link 67, rotates the closing'lever 63 in a clockwise direction resetting the toggle l73, 75 and relatching the'latchmember 87 Vwith the trigger latch 99. vThe leftward movement of the armature 69'isfarrested-by engagement ofthe link 67 with a. xed stop 153. The-mechanism is now in condition to be closed by energization of the closing solenoid 27.
:Energization of the closing solenoid 27 attracts the armature 69 toward the right which movement, through the link 67, rotates the `closing lever 63 counterclockwise about its pivot 65. Since the'latch member 87 is now held by the'latch 99, the link -89 holds the toggle 73, 75 in `thrust Itransmitting 'condition causing the toggle to transmit'the force "of the armature 69 to the operating bell crank'lever 55 which thrusts the operating rod y '45 upwardly to close the breaker.. At the end of the closing stroke the latch-83 reengages the rollers 85 and holds the mechanism in the closed position.
YAn'irnportant feature of the invention'is the construction and arrangement of the tripping electromagnet whereby the? leakage ux is reduced which reduces the inductance of the energizing coil and increases Vtheinitial `rate of rise of ilux across the'working air gap and with it, the rate of build-up of the pull of the magnet. It has been found that by placing pieces of a material of high conductivity/,'such, forY instance, as copper in the pathofunusable leakage flux, the eddy currents in the conductive material retard the build-up of the leakage uiilr vandfelectively reduce the initial inductance of thel co Referring to Figs. `3, Siand 6, the electromagnet comprises, zas :previously :.described, the fixed .iE-shapedv magnet yoke..1.13 .rigidly held .between the upper-,and lower .platesll andzlll :respectively by ,thebolts 119. The '11131651115 V2and...117.;ate .madeoa material having high .cpnduetivitmsucln.for instance,:as::copper. Between the 'p1ates1115 1\and .117 respectively, .and z the magnet yoke i113 are disposed ...U ,shaped-.pieces -ofv insulation 15.5. A .UsshapedstriplSTpf insulation surrounds .three4 edges ing material is disposed around the insulating strip 157 and `between the latter andthe bolts 11-9 as clearly-seen in Figs. 3 and 5. Strips l161 of conducting material disposed one on each side of the coil 126 between the coil and the outer legs of the magnet yoke, have their inner ends formed at right angles toward each other between the inner end of the coil and 'the magnetr yoke. Insulat ing strips 163 of .the-sameshape as 4the conducting strips 161 are disposed between the latter and the outer legs 'ofthemagnet yoke.
The 'facing sides of thelplates 115-and 117 are recessed as 4at v*165 to receive the coilV 126 and the spool -1767 yon which it is wound. Spacers 169 of lconducting-material are placed in .the grooves 165 betweenthe inner end of the coil 1'26 and outer end of the plates 115 and 117, and are held in-placeby"one of the"bolts"1'19 which passes through openings in the plates and 117 and in the spacers 169. j
'The plates 1'15and "117 (Figs. k5 and 6) extend-downwardly adjacent "the sides of the armature 127 and the endsA of the U-shaped conducting strip-1,59 extend down.- wardly adjacent the ends of the armature 127. This arrangement prevents vthe ilux from Haring outward to the'sides-of the'endpole faces and concentrates* the flux directlyj across the air gaps thereby increasing `the pull on the armature.
It -will be seen that all of the surfaces ofthe magnet yoke, except the center'leg of themagnet yoke and-thc Vthree'polefaces, have a conductive path adjacent them.
Tests'on one embodiment of the invention have *shown that the use of such-'conductive paths reduced the coil inductance from .024 henry to .'017 henry. "Ihis reduced the time to'reach 63% pull from .007 second to .005second which reduced the tripping time .002 second or 29%. j
The yfast `interrupting time provided by the invention will'effect considerable'reduction in wire damage in clearing faults on overhead lines, thereby permitting improved continuity of 'service and reduceline maintenance. Y
Having described the invention in accordance with the provisions of the patent statutes, it is to lne/understood that various changes and modifications may be madein the structural details land in the arrangement vof `parts without departing from the spirit of they invention.
We claim as our invention:
.1. An electromagnetic trip Vdevice'ior a circuit breaker comprising a magnet yoke, a pair ofspacedfrigid members of highly conductive material disposed on opposite sides of said magnet yoke, energizing means on said magnet` yoke, and a plurality of conducting'members of highly conductive material disposedadjacent the edge portions of said magnet'yoke to vreduce-'the leakage-'tink of said magnet yoke and thereby increase the rate rof build-up of useful tlux.
2. An electromagnetic trip device for a circuit breaker comprising a laminated magnet yoke, *a* pair of spaced rigid members of 'a highly `conductive -material between which said laminated magnet yoke is disposed, a U-shaped strip otra highly conducting material disposed adjacent three edges of said laminated 4magnet yoke to reduce the leakage ux of said magnet yoke.
3. An electromagnetic trip device'for -a circuit-breaker comprising a magnet yoke, a pair of'rigidV members of highly conductive-material supporting said 'magnetyokc between them, members of insulating material disposed Vbetween said rigid members and-said magnet yoke, 1a
`bers of a., highly conductivesmaterialhavingtsaid E-Shtlped magnet yoke disposed betweenthem,angcnellillgcoil/ mounted on the center leg of said magnet yoke, and conducting strips of a highly conductive material adjacent the edge portions of said magnet yoke, said rigid members and said conductive strips reducing the leakage flux of said magnet yoke.
5. An electromagnetic trip device for a circuit breaker comprising a laminated E-shaped magnet yoke, a pair of relatively thick plates of a highly conductive material disposed one on each side of said magnet yoke, an energizing coil mounted on one of the legs of said E-shaped magnet yoke, and conducting strips of a highly conductive material disposed adjacent portions of the edges of said laminated magnet yoke, said plates and said conducting strips reducing the leakage llux of said magnet yoke.
6. An electroresponsive device comprising a rectangular E-shaped magnet yoke, a pair of plates of a highly conductive material disposed on opposite sides of said magnet yoke, said plates being larger than said magnet yoke, securing means securing said plates together to support said magnet yoke, an energizing coil mounted on the center leg of said magnet yoke, said plates being recessed to receive said energizing coil,-and a U-shaped conducting strip of a highly conductive material disposed around three sides of said magnet yoke between said magnet yoke and said securing means, said plates and said conducting strip reducing the leakage ilux of said magnet yoke.
7. An electroresponsive device comprising an' E-shaped laminated magnet yoke having three pole faces, a pair of plates of a highly conductive material disposed on opposite faces of said laminated magnet yoke and secured together to mount said magnet yoke, yan energizing coil surrounding the middle leg of said magnet yoke, a U-shaped conducting strip of a highly conductive material surrounding the edges of said magnet yoke except the pole faces, conducting strips of a highly conductive material disposed `between said coil and the inner edges of the outer legs of said magnet yoke, said plates and said conducting strips reducing the leakage ux of said magnet yoke.
8. An electroresponsive device comprising an E-shaped laminated magnet yoke having three pole faces, a pair of plates of a highly conductive material disposed on opposite faces of said laminated magnet yoke and secured together to mount said magnet yoke, members of insulating material between said plates and said magnet yoke, an energizing coil surrounding the middle leg of said magnet yoke, a U-shaped conducting strip of a highly conductive material surrounding the edges of said magnet yoke except the pole faces, conducting strips of a highly conductive material disposed between said coil and the inner edges of the outer legs of said magnet yoke, insulating means between each of said conducting strips and said magnet yoke, said plates and said conducting strips reducing the leakage llux of said magnet yoke.
9. A tractive electroresponsive device comprising a magnet yoke, a pair o-f members of a highly conductive non-magnetic material disposed on opposite sides of said magnet yoke, and means of a highly conductive nonmagnetic material disposed adjacent the edge portions of said magnet yoke, insulating means disposed between said highly conductive non-magnetic materials and said magnetic yoke, said insulating means being substantially thin to enable said highly conductive non-magnetic materials to be positioned in close enough proximity to said magnet yoke to effectively reduce the leakage flux and thereby increase the rate of build-up of useful ux.
l0. A tractive electroresponsive device comprising a fixed magnet yoke and a movable armature, an energizing coil on said magnet yoke, 4and shielding means of a highly conductive non-magnetic material surrounding said magnet yoke except the portion adjacent said armature, said shielding means being in close enough proximity to said magnet yoke to effectively reduce the leakage flux in said magnet yoke to thereby increase the rate of buildup of useful flux.
ll. A tractive electromagnetic device comprising a magnet yoke having a plurality of pole faces, a movable armature providing a plurality of air gaps, an energizing coil on said magnet yoke, a shield of a highly conductive material surrounding said electromagnet except the portion thereof adjacent said armature, said shield being disposed proximate to said magnet yoke to reduce the leakage flux in said magnet yoke to thereby increase the rate of build-up of useful flux across said air gaps, and portions of said shield extending adjacent the ends of said `armature to elfect a concentration of flux at said pole faces.
l2. A tractive electromagnet comprising `a magnet yoke having a plurality of pole faces, a movable armature disposed adjacent said pole faces providing a plurality of air gaps, an energizing coil on said -magnet yoke, shielding means comprising a pair of members of a highly conductive material disposed at opposite sides of said magnet yoke, a shield of a highly conductive material surrounding the edges of said magnet yoke proximate thereto except the pole faces, said shielding means and said shield reducing the leakage ux to thereby increase the build-up of useful flux across said air gaps, and the end portions of said shield extending beyond said pole faces and adjacent the ends of said armature to effect concentration of flux at said pole faces.
References Cited in the file of this patent UNITED STATES PATENTS 650,915 Scribner et al. June 5, 1900 1,576,155 Stevens Mar. 9, 1926 2,348,556 Matthias May 9, 1944
US629606A 1956-12-20 1956-12-20 Circuit breaker Expired - Lifetime US2939931A (en)

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DEW22382A DE1045524B (en) 1956-12-20 1957-12-09 Electromagnetic tripping device for electrical switches

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US650915A (en) * 1898-02-14 1900-06-05 Western Electric Co Relay for telephone-lines.
US1576155A (en) * 1924-05-24 1926-03-09 Gen Electric Electromagnet
US2348556A (en) * 1941-11-05 1944-05-09 Allen Bradley Co Magnet structure

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US650915A (en) * 1898-02-14 1900-06-05 Western Electric Co Relay for telephone-lines.
US1576155A (en) * 1924-05-24 1926-03-09 Gen Electric Electromagnet
US2348556A (en) * 1941-11-05 1944-05-09 Allen Bradley Co Magnet structure

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