EP0147278B1 - Thermal-magnetic tripping mechanism of a circuit breaker made of shape memory effect material - Google Patents

Thermal-magnetic tripping mechanism of a circuit breaker made of shape memory effect material Download PDF

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Publication number
EP0147278B1
EP0147278B1 EP84402508A EP84402508A EP0147278B1 EP 0147278 B1 EP0147278 B1 EP 0147278B1 EP 84402508 A EP84402508 A EP 84402508A EP 84402508 A EP84402508 A EP 84402508A EP 0147278 B1 EP0147278 B1 EP 0147278B1
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EP
European Patent Office
Prior art keywords
spring
thermal
coil
shape memory
core
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
Application number
EP84402508A
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German (de)
French (fr)
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EP0147278A2 (en
EP0147278A3 (en
Inventor
Louis Boillot
William Bartolo
Patrick Perdigon
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Merlin Gerin SA
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Merlin Gerin SA
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Priority to AT84402508T priority Critical patent/ATE31590T1/en
Publication of EP0147278A2 publication Critical patent/EP0147278A2/en
Publication of EP0147278A3 publication Critical patent/EP0147278A3/en
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Publication of EP0147278B1 publication Critical patent/EP0147278B1/en
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    • 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
    • H01H71/10—Operating or release mechanisms
    • H01H71/12—Automatic release mechanisms with or without manual release
    • H01H71/40—Combined electrothermal and electromagnetic mechanisms
    • 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
    • H01H71/10—Operating or release mechanisms
    • H01H71/12—Automatic release mechanisms with or without manual release
    • H01H71/14—Electrothermal mechanisms
    • H01H71/145—Electrothermal mechanisms using shape memory materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H61/00—Electrothermal relays
    • H01H61/01—Details
    • H01H61/0107—Details making use of shape memory materials
    • H01H2061/0115—Shape memory alloy [SMA] actuator formed by coil spring
    • 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
    • H01H71/10—Operating or release mechanisms
    • H01H71/12—Automatic release mechanisms with or without manual release
    • H01H71/40—Combined electrothermal and electromagnetic mechanisms
    • H01H2071/407—Combined electrothermal and electromagnetic mechanisms the thermal element being heated by the coil of the electromagnetic mechanism

Definitions

  • a known magnetothermal trip of the kind mentioned is described in European patent application No. 37490.
  • This type of trip device does not have a bimetallic strip and the means for unlocking the lock associated with the mechanism are actuated by the movable core in the event of a short circuit, and by the thermomechanical sensor in shape memory alloy in the event of overload.
  • the triggering of the mechanism requires two separate mechanical connections cooperating respectively with the sensor and the movable core.
  • the implementation of such a trip device is complicated, and it is also essential to adapt the thermomechanical sensor to each rating of the circuit breaker.
  • the object of the invention is to remedy these drawbacks and to allow the production of a reliable magnetothermal trip unit and of simplified structure using the same thermomechanical sensor for all the ratings of a range of circuit breakers.
  • the thermomechanical sensor in shape memory alloy comprises a helical spring, housed in an enclosed space inside the insulating sleeve for supporting the coil.
  • the number of ampere-turns of the coil is constant for all the calibers of a range.
  • the insulating sheath of the control coil is formed by a tubular sleeve closed at one of its ends by a bottom and at the opposite end by the fixed core.
  • the shape memory spring and the movable core are arranged coaxially in the closed space between the fixed core and the bottom of the sheath and are capable of causing a single unlocking pusher passing axially through the fixed core.
  • the release button is associated with a return spring which serves at the same time as a return spring for the movable core and as a polarization member for the shape memory spring.
  • the shape memory spring surrounds the movable core, bearing on the bottom of the sheath, and cooperating at its opposite end with a magnetic pallet capable of moving the pusher towards the active triggering position by axial extension of the comes out after the critical temperature has been exceeded in the closed space while the moving core remains stationary in the separated position.
  • the magnetic pallet has a bridge shape, one of the faces of which is fitted with a guide pin mounted to slide axially in a hole in the movable core, and the other side of which cooperates with the release button.
  • the shape memory spring is arranged inside the movable core in the form of a hollow sleeve, the pusher drive head being directly in contact with the shape memory spring.
  • Adjustment means are provided for adjusting the air gap and the opposing force of the return spring of the unlocking pusher.
  • thermomagnetic trip device 10 of a miniature circuit breaker comprises a control coil 12 mounted on an insulating sheath 14 in the form of a tubular sleeve, closed at one of its ends by a bottom 16.
  • a fixed magnetic core 18 Inside the sheath 14 is a fixed magnetic core 18 separated from a plunger core 20 sliding by an axial gap 22.
  • an actuating rod or extractor 24 To the plunger magnetic core 20 is secured an actuating rod or extractor 24 which passes through an orifice 26 formed in the bottom 16 of the sleeve 14.
  • the active end of the extractor 24 is capable of actuating a contact arm 28 pivotally mounted on an axis 30.
  • the plunger core 20 cooperates on its opposite side with an unlocking pusher 32 or striker which extends axially along a central opening 34 of the fixed core 18 while being urged to bear against the plunger core 20 by a return spring 36.
  • the active end of the pusher 32 cooperates with a latch 38 or a trigger bar, intended to cause the automatic triggering of the mechanism 40 when an overcurrent detected by the trigger 10.
  • the structure of the mechanism 40 is described in detail in European patent application 27404.
  • the coil 12 of the trigger 10 is crossed by the total current or by a fraction of the current flowing in the pole.
  • the enclosed space 42 arranged inside the sheath 14 between the core fixed 18 and the bottom 16 is the seat of a predetermined heating representing the image of the intensity of the excitation current of the coil 12.
  • thermomechanical sensor 44 composed of a shape memory alloy is housed in the enclosed space 42 of the sleeve 14 i and is shaped as a helical spring 46 arranged coaxially with play around the plunger core 20.
  • the shape memory spring 46 is interposed between the bottom 16 and one of the bearing faces of a magnetic pallet 48 in the form of a bridge, the opposite face of which cooperates with the unlocking pusher 32.
  • the pallet 48 is provided with a guide pin 50 capable of sliding axially in a blind hole 52 of the plunger core 20 opposite the extractor 24.
  • the critical transformation temperature of the shape memory alloy depends on the material chosen and on the opposing polarization force of the return spring 36. It is advantageously between 90 degrees C and 100 degrees C, and constitutes the thermal tripping temperature. .
  • the helical spring 46 In the initial state of rest, the helical spring 46 remains with contiguous turns when the temperature in the space 42 is lower than the transformation temperature of the alloy (FIG. 1). In the active state, the spring 46 is deformed by axial elongation of a few millimeters in the direction of the arrow F I in the event of the thermal trip temperature being exceeded. The deformation of the spring 46 takes place against the return spring 36 and drives the push-button 32 for unlocking the lock 38 in the same direction.
  • the alloy has a simple memory effect with unidirectional deformation in the direction of the arrow F i .
  • the return spring 36 of the pusher 32 cooperates with the pallet 48 to recompress the spring 46 with shape memory towards its initial position with contiguous turns.
  • the return to the state of rest of the spring 46 is automatic in the case of a reversible memory effect alloy with bidirectional deformation.
  • thermomagnetic trip device 10 The operation of the thermomagnetic trip device 10 according to FIG. 1 is as follows:
  • a circulation in the coil 12 of a current of high intensity, in particular of short-circuit, causes an instantaneous triggering by magnetic attraction of the assembly core plunger 20 and pallet 48 against the polar faces of the fixed core 18.
  • the pusher 32 unlocks the latch 38 and the extractor 24 simultaneously pulls on the pivoting contact arm 28.
  • the final opening of the contacts is then confirmed after triggering of the mechanism 40.
  • the electromagnetic triggering threshold depends on the intensity of the excitation current in the coil 12 and is a function of the air gap 22 and the stiffness of the return spring. 36 of the compression type.
  • the spring 46 with shape memory does not have time to react because of the thermal inertia of the space 42, and it remains in the rest state.
  • the return spring 36 of the pusher 32 cooperates simultaneously with the plunger core 20 and the spring 46 with shape memory.
  • the trigger is adjusted by varying the preload of the return spring 36 by means of a screw 54 or adjustable ring in a tapped hole 56 of the fixed core 18.
  • the rotation of the screw 54 keeps the air gap 22 constant, and acts exclusively on the preload of the return spring 30 which simultaneously modifies the electromagnetic tripping threshold and the thermal tripping characteristic.
  • FIG. 2 the same reference numbers designate parts which are identical or similar to those in FIG. 1.
  • the return spring 36 of the pusher 32 is supported on a collar 57 of the fixed core 18, the latter being formed by a self-tapping screw screwing into the sheath 14.
  • the plunger core 20 has a hollow sleeve inside which houses the shape memory spring 46.
  • the drive head of the pusher 32 bears directly on the spring 46 with shape memory.
  • the operation of this trigger is similar to that described with reference to FIG. 1, except the trigger setting which is different. This adjustment is effected by screwing or unscrewing the fixed core 18 in the sheath 14 resulting in a combined variation of the length of the air gap 22 and of the opposing force of the return spring 36.
  • the 'air gap 22 increases at the same time as the force of the return spring 36 decreases. Conversely, if the core 18 is screwed on, the air gap 22 decreases and the opposing force of the spring 36 increases. The combined variation of these two parameters keeps the electromagnetic trigger threshold substantially constant.
  • the adjustment of the fixed core 18 essentially modifies the thermal triggering characteristic of the spring 46 with shape memory by virtue of the variation in the preload of the return spring 36.
  • the arrangement of the spring 46 with shape memory inside the enclosed space 42 may be different from that shown in FIGS. 1 and 2.
  • the adoption of the appropriate coil 12 makes it possible to keep constant heating in the enclosed space 42 whatever the caliber chosen. A full range can thus be produced by keeping all the parts of the trigger 10 with the exception of the coil 12.
  • An adjustment member made of a material of predetermined thermal conductivity, is inserted between the coil 12 and the spring 46 with shape memory to adjust the thermal time constant in space 42.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Breakers (AREA)
  • Thermally Actuated Switches (AREA)

Abstract

1. Thermal-magnetic trip device with a mechanism (40) of an electric circuit breaker comprising : - a stationary core (18) associated with a movable core (20) sliding by means of an air-gap (22), - a tubular control coil (12) surrounding coaxially said stationary and movable cores (18, 20), the air-gap (22) being crossed by a magnetic flux due to the passage of the current in the coil (12), - a spring (36) resetting the movable core (20) in spreaded position when the current intensity for excitation of the coil (12) is lower than the electromagnetic trip threshold, - a thermomechanical sensor (44) of shape memory effect alloy, sensitive for the temperature rise of the control coil (12), - and unlocking means cooperating with the movable core (20) and the thermomechanical sensor (44) to ensure the automatic tripping of the mechanism (40), characterized by the fact that the thermomechanical sensor (44) of shape memory effect alloy comprises a helical spring (46) arranged in a closed space (42) insides the insulating duct (14) supporting the coil (12), and that the ampere-turn number of the coil (12) is constant for all sizes of a range.

Description

L'invention est relative à un déclencheur magnétothermique associé à un mécanisme d'un disjoncteur électrique comprenant :

  • - un noyau fixe associé à un noyau mobile coulissant par l'intermédiaire d'un entrefer,
  • - une bobine de commande tubulaire entourant coaxialement lesdits noyaux fixe et mobile, l'entrefer étant traversé par un flux magnétique dû au passage du courant dans la bobine,
  • un ressort de rappel du noyau mobile en position écartée lorsque l'intensité du courant d'excitation de la bobine est inférieure au seuil de déclenchement électromagnétique,
  • un capteur thermomécanique en alliage à mémoire de forme, sensible à l'échauffement de la bobine de commande,
  • et des moyens de déverrouillage coopérant avec le noyau mobile et le capteur thermomécanique pour assurer le déclenchement automatique du mécanisme.
The invention relates to a thermomagnetic trip device associated with a mechanism of an electric circuit breaker comprising:
  • - a fixed core associated with a movable sliding core via an air gap,
  • a tubular control coil coaxially surrounding said fixed and movable cores, the air gap being traversed by a magnetic flux due to the passage of current in the coil,
  • a return spring of the movable core in the separated position when the intensity of the excitation current of the coil is less than the electromagnetic tripping threshold,
  • a thermomechanical sensor in shape memory alloy, sensitive to the heating of the control coil,
  • and unlocking means cooperating with the movable core and the thermomechanical sensor to ensure the automatic triggering of the mechanism.

Un déclenchement magnétothermique connu du genre mentionné est décrit dans la demande de brevet européen N° 37490. Ce type de déclencheur est dépourvu de bilame et les moyens de déverrouillage du verrou associé au mécanisme sont actionnés par le noyau mobile en cas de court-circuit, et par le capteur thermomécanique en alliage à mémoire de forme en cas de surcharge. Le déclenchement du mécanisme nécessite deux liaisons mécaniques distinctes coopérant respectivement avec le capteur et le noyau mobile. La mise en oeuvre d'un tel déclencheur est compliquée, et il est d'autre part indispensable d'adapter le capteur thermomécanique à chaque calibre du disjoncteur.A known magnetothermal trip of the kind mentioned is described in European patent application No. 37490. This type of trip device does not have a bimetallic strip and the means for unlocking the lock associated with the mechanism are actuated by the movable core in the event of a short circuit, and by the thermomechanical sensor in shape memory alloy in the event of overload. The triggering of the mechanism requires two separate mechanical connections cooperating respectively with the sensor and the movable core. The implementation of such a trip device is complicated, and it is also essential to adapt the thermomechanical sensor to each rating of the circuit breaker.

L'invention a pour but de remédier à ces inconvénients et de permettre la réalisation d'un déclencheur magnétothermique fiable et de structure simplifiée utilisant le même capteur thermomécanique pour tous les calibres d'une gamme de disjoncteurs.The object of the invention is to remedy these drawbacks and to allow the production of a reliable magnetothermal trip unit and of simplified structure using the same thermomechanical sensor for all the ratings of a range of circuit breakers.

Selon l'invention, le capteur thermomécanique en alliage à mémoire de forme comporte un ressort hélicoïdal, logé dans un espace clos à l'intérieur du fourreau isolant de support de la bobine. Le nombre d'ampères-tours de la bobine est constant pour tous les calibres d'une gamme. Le fourreau isolant de la bobine de commande est formé par un manchon tubulaire fermé à l'une de ses extrémités par un fond et à l'extrémité opposée par le noyau fixe. Le ressort à mémoire de forme et le noyau mobile sont agencés coaxialement dans l'espace clos entre le noyau fixe et le fond du fourreau et sont susceptibles d'entraîner un poussoir unique de déverrouillage traversant axialement le noyau fixe.According to the invention, the thermomechanical sensor in shape memory alloy comprises a helical spring, housed in an enclosed space inside the insulating sleeve for supporting the coil. The number of ampere-turns of the coil is constant for all the calibers of a range. The insulating sheath of the control coil is formed by a tubular sleeve closed at one of its ends by a bottom and at the opposite end by the fixed core. The shape memory spring and the movable core are arranged coaxially in the closed space between the fixed core and the bottom of the sheath and are capable of causing a single unlocking pusher passing axially through the fixed core.

Le poussoir de déverrouillage est associé à un ressort de rappel qui sert en même temps de ressort de rappel au noyau mobile et d'organe de polarisation au ressort à mémoire de forme.The release button is associated with a return spring which serves at the same time as a return spring for the movable core and as a polarization member for the shape memory spring.

Selon un premier mode de réalisation le ressort à mémoire de forme entoure le noyau mobile en prenant appui sur le fond du fourreau, et coopérant par son extrémité opposée avec une palette magnétique susceptible de déplacer le poussoir vers la position active de déclenchement par allongement axial du ressort suite au dépassement de la température critique dans l'espace clos pendant que le noyau mobile reste immobile en position écartée. La palette magnétique présente une forme en pont dont l'une des faces est équipée d'un tenon de guidage monté à coulissement axial dans un trou du noyau mobile, et dont l'autre face coopère avec le poussoir de déverrouillage.According to a first embodiment, the shape memory spring surrounds the movable core, bearing on the bottom of the sheath, and cooperating at its opposite end with a magnetic pallet capable of moving the pusher towards the active triggering position by axial extension of the comes out after the critical temperature has been exceeded in the closed space while the moving core remains stationary in the separated position. The magnetic pallet has a bridge shape, one of the faces of which is fitted with a guide pin mounted to slide axially in a hole in the movable core, and the other side of which cooperates with the release button.

Selon un deuxième mode de réalisation, le ressort à mémoire de forme est agencé à l'intérieur du noyau mobile en forme de manchon creux, la tête d'entraînement du poussoir étant directement en contact avec le ressort à mémoire de forme.According to a second embodiment, the shape memory spring is arranged inside the movable core in the form of a hollow sleeve, the pusher drive head being directly in contact with the shape memory spring.

Des moyens de réglage sont prévus pour ajuster l'entrefer et la force antagoniste du ressort de rappel du poussoir de déverrouillage.Adjustment means are provided for adjusting the air gap and the opposing force of the return spring of the unlocking pusher.

D'autres avantages et caractéristiques ressortiront plus clairement de l'exposé qui va suivre de différents modes de réalisation de l'invention, donnés à titre d'exemples non limitatifs et représentés aux dessins annexés, dans lesquels :

  • la figure 1 est une vue en coupe axiale d'un déclencheur selon l'invention, représenté en position de repos ;
  • la figure 2 est une vue identique de la figure 1, d'une variante de réalisation.
Other advantages and characteristics will emerge more clearly from the description which follows of different embodiments of the invention, given by way of nonlimiting examples and represented in the appended drawings, in which:
  • Figure 1 is an axial sectional view of a trip device according to the invention, shown in the rest position;
  • Figure 2 is an identical view to Figure 1, of an alternative embodiment.

Sur la figure 1, un déclencheur magnétothermique 10 d'un disjoncteur miniature comporte une bobine 12 de commande montée sur un fourreau 14 isolant en forme de manchon tubulaire, obturé à l'une de ses extrémités par un fond 16. A l'intérieur du fourreau 14 se trouve un noyau magnétique fixe 18 séparé d'un noyau plongeur 20 coulissant par un entrefer 22 axial. Au noyau magnétique plongeur 20 est solidarisée une tige d'actionnement ou extracteur 24 qui traverse un orifice 26 ménagé dans le fond 16 du fourreau 14. Le bout actif de l'extracteur 24 est susceptible d'actionner un bras de contact 28 monté à pivotement sur un axe 30. Le noyau plongeur 20 coopère par son côté opposé avec un poussoir 32 de déverrouillage ou percuteur qui s'étend axialement le long d'une ouverture 34 centrale du noyau fixe 18 en étant sollicité en appui du noyau plongeur 20 par un ressort de rappel 36. L'extrémité active du poussoir 32 coopère avec un verrou 38 ou une barre de déclenchement, destiné à provoquer le déclenchement automatique du mécanisme 40 lors de l'apparition d'une surintensité détectée par le déclencheur 10. La structure du mécanisme 40 est décrite en détail dans la demande de brevet européen 27404.In FIG. 1, a thermomagnetic trip device 10 of a miniature circuit breaker comprises a control coil 12 mounted on an insulating sheath 14 in the form of a tubular sleeve, closed at one of its ends by a bottom 16. Inside the sheath 14 is a fixed magnetic core 18 separated from a plunger core 20 sliding by an axial gap 22. To the plunger magnetic core 20 is secured an actuating rod or extractor 24 which passes through an orifice 26 formed in the bottom 16 of the sleeve 14. The active end of the extractor 24 is capable of actuating a contact arm 28 pivotally mounted on an axis 30. The plunger core 20 cooperates on its opposite side with an unlocking pusher 32 or striker which extends axially along a central opening 34 of the fixed core 18 while being urged to bear against the plunger core 20 by a return spring 36. The active end of the pusher 32 cooperates with a latch 38 or a trigger bar, intended to cause the automatic triggering of the mechanism 40 when an overcurrent detected by the trigger 10. The structure of the mechanism 40 is described in detail in European patent application 27404.

La bobine 12 du déclencheur 10 est traversée par le courant total ou par une fraction du courant circulant dans le pôle. L'espace 42 clos agencé à l'intérieur du fourreau 14 entre le noyau fixe 18 et le fond 16 est le siège d'un échauffement prédéterminé représentant l'image de l'intensité du courant d'excitation de la bobine 12.The coil 12 of the trigger 10 is crossed by the total current or by a fraction of the current flowing in the pole. The enclosed space 42 arranged inside the sheath 14 between the core fixed 18 and the bottom 16 is the seat of a predetermined heating representing the image of the intensity of the excitation current of the coil 12.

Un capteur thermomécanique 44 composé d'un alliage à mémoire de forme est logé dans l'espace 42 clos du fourreau 14i et est conformé en ressort 46 hélicoïdal disposé coaxialement avec jeu autour du noyau plongeur 20. Le ressort 46 à mémoire de forme est intercalé entre le fond 16 et l'une des faces d'appui d'une palette 48 magnétique en forme de pont dont la face opposée coopère avec le poussoir 32 de déverrouillage. La palette 48 est dotée d'un tenon 50 de guidage susceptible de coulisser axialement dans un trou 52 borgne du noyau plongeur 20 à l'opposé de l'extracteur 24.A thermomechanical sensor 44 composed of a shape memory alloy is housed in the enclosed space 42 of the sleeve 14 i and is shaped as a helical spring 46 arranged coaxially with play around the plunger core 20. The shape memory spring 46 is interposed between the bottom 16 and one of the bearing faces of a magnetic pallet 48 in the form of a bridge, the opposite face of which cooperates with the unlocking pusher 32. The pallet 48 is provided with a guide pin 50 capable of sliding axially in a blind hole 52 of the plunger core 20 opposite the extractor 24.

La température critique de transformation de l'alliage à mémoire de forme dépend du matériau choisi et de la force antagoniste de polarisation du ressort de rappel 36. Elle se situe avantageusement entre 90 degrés C et 100 degrés C, et constitue la température de déclenchement thermique. Dans l'état initial de repos, le ressort 46 hélicoïdal reste à spires jointives lorsque la température dans l'espace 42 est inférieure à la température de transformation de l'alliage (fig. 1). Dans l'état actif, le ressort 46 se déforme par allongement axial de quelques millimètres dans le sens de la flèche FI en cas de dépassement de la température de déclenchememt thermique. La déformation du ressort 46 s'effectue à l'encontre du ressort de rappel 36 et entraîne le poussoir 32 de déverrouillage du verrou 38 dans le même sens. L'alliage présente un effet de mémoire simple à déformation unidirectionnelle dans le sens de la flèche Fi. Lorsque la température dans l'espace 42 clos redescend sous la température de transformation de l'alliage, le ressort 36 de rappel du poussoir 32 coopère avec la palette 48 pour recomprimer le ressort 46 à mémoire de forme vers sa position initiale à spires jointives.The critical transformation temperature of the shape memory alloy depends on the material chosen and on the opposing polarization force of the return spring 36. It is advantageously between 90 degrees C and 100 degrees C, and constitutes the thermal tripping temperature. . In the initial state of rest, the helical spring 46 remains with contiguous turns when the temperature in the space 42 is lower than the transformation temperature of the alloy (FIG. 1). In the active state, the spring 46 is deformed by axial elongation of a few millimeters in the direction of the arrow F I in the event of the thermal trip temperature being exceeded. The deformation of the spring 46 takes place against the return spring 36 and drives the push-button 32 for unlocking the lock 38 in the same direction. The alloy has a simple memory effect with unidirectional deformation in the direction of the arrow F i . When the temperature in the enclosed space 42 drops below the transformation temperature of the alloy, the return spring 36 of the pusher 32 cooperates with the pallet 48 to recompress the spring 46 with shape memory towards its initial position with contiguous turns.

Le retour à l'état de repos du ressort 46 est automatique dans le cas d'un alliage à effet de mémoire réversible à déformation bidirectionnelle.The return to the state of rest of the spring 46 is automatic in the case of a reversible memory effect alloy with bidirectional deformation.

Le fonctionnement du déclencheur magnétothermique 10 selon la figure 1 est le suivant :The operation of the thermomagnetic trip device 10 according to FIG. 1 is as follows:

Déclenchement sur court-circuitShort circuit trip

Une circulation dans la bobine 12 d'un courant de forte intensité, notamment de court-circuit, provoque un déclenchement instantané par attraction magnétique de l'ensemble noyau plongeur 20 et palette 48 contre les faces polaires du noyau fixe 18. Le poussoir 32 déverrouille le verrou 38 et l'extracteur 24 tire simultanément sur le bras de contact 28 pivotant. L'ouverture définitive des contacts est ensuite confirmée après déclenchement du mécanisme 40. Le seuil de déclenchement électromagnétique dépend de l'intensité du courant d'excitation dans la bobine 12 et est fonction de l'entrefer 22 et de la raideur du ressort de rappel 36 du type à compression. Le ressort 46 à mémoire de forme n'a pas le temps de réagir à cause de l'inertie thermique de l'espace 42, et il reste à l'état de repos.A circulation in the coil 12 of a current of high intensity, in particular of short-circuit, causes an instantaneous triggering by magnetic attraction of the assembly core plunger 20 and pallet 48 against the polar faces of the fixed core 18. The pusher 32 unlocks the latch 38 and the extractor 24 simultaneously pulls on the pivoting contact arm 28. The final opening of the contacts is then confirmed after triggering of the mechanism 40. The electromagnetic triggering threshold depends on the intensity of the excitation current in the coil 12 and is a function of the air gap 22 and the stiffness of the return spring. 36 of the compression type. The spring 46 with shape memory does not have time to react because of the thermal inertia of the space 42, and it remains in the rest state.

Déclenchement à la suite d'une surchargeTriggering after an overload

En présence d'un courant de surcharge dont l'intensité est comprise entre l'intensité nominale du disjoncteur et le seuil de déclenchement électromagnétique, le champ magnétique dans l'entrefer 22 est insuffisant pour attirer le noyau mobile 20 et l'extracteur 24 qui restent immobiles en position écartée (fig. 1). L'échauffement progressif de l'espace 42 permet d'atteindre la température critique de déformation du ressort 46 à mémoire de forme. Il en résulte un déclenchement thermique temporisé à temps inverse par allongement axial du ressort 46 dans le sens de la flèche Fl, qui entraîne la palette 48 et le poussoir 32 vers la position déverrouillée du verrou 38. Les contacts s'ouvrent après déclenchement du mécanisme 40, et la bobine 12 n'est plus parcourue par le courant. Le ressort 46 revient ensuite à l'état de repos dès que la température à l'intérieur de l'espace 42 redescend sous la température de déclenchement thermique.In the presence of an overload current whose intensity is between the nominal intensity of the circuit breaker and the electromagnetic tripping threshold, the magnetic field in the air gap 22 is insufficient to attract the movable core 20 and the extractor 24 which remain stationary in the open position (fig. 1). The gradual heating of the space 42 makes it possible to reach the critical deformation temperature of the spring 46 with shape memory. This results in a time-delayed thermal tripping in reverse time by axial elongation of the spring 46 in the direction of the arrow F l , which drives the pallet 48 and the pusher 32 towards the unlocked position of the latch 38. The contacts open after tripping of the mechanism 40, and the coil 12 is no longer traversed by the current. The spring 46 then returns to the rest state as soon as the temperature inside the space 42 drops below the thermal trigger temperature.

Réglage du déclenchementTrigger setting

Le ressort 36 de rappel du poussoir 32 coopère simultanément avec le noyau plongeur 20 et le ressort 46 à mémoire de forme. Le réglage du déclenchement s'opère par variation de la précontrainte du ressort de rappel 36 au moyen d'une vis 54 ou bague ajustable dans un trou 56 taraudé du noyau fixe 18. La rotation de la vis 54 garde l'entrefer 22 constant, et agit exclusivement sur la précontrainte du ressort de rappel 30 qui modifie simultanément le seuil de déclenchement électromagnétique et la caractéristique de déclenchement thermique.The return spring 36 of the pusher 32 cooperates simultaneously with the plunger core 20 and the spring 46 with shape memory. The trigger is adjusted by varying the preload of the return spring 36 by means of a screw 54 or adjustable ring in a tapped hole 56 of the fixed core 18. The rotation of the screw 54 keeps the air gap 22 constant, and acts exclusively on the preload of the return spring 30 which simultaneously modifies the electromagnetic tripping threshold and the thermal tripping characteristic.

Sur la figure 2, les mêmes numéros de repères désignent des pièces identiques ou similaires à celles de la fig. 1. Le ressort 36 de rappel du poussoir 32 prend appui sur un collet 57 du noyau fixe 18, ce dernier étant formé par une vis autota- raudeuse se vissant dans le fourreau 14. Le noyau plongeur 20 comporte un manchon creux à l'intérieur duquel est logé le ressort 46 à mémoire de forme. La tête d'entraînement du poussoir 32 prend directement appui sur le ressort 46 à mémoire de forme. Le fonctionnement de ce déclencheur est similaire à celui décrit en référence à la fig. 1, sauf le réglage du déclenchement qui est différent. Ce réglage s'opère par vissage ou dévissage du noyau fixe 18 dans le fourreau 14 entraînant une variation combinée de la longueur de l'entrefer 22 et de l'effort antagoniste du ressort de rappel 36. En cas de dévissage du noyau 18, l'entrefer 22 augmente en même temps que l'effort du ressort de rappel 36 diminue. Réciproquement, en cas de vissage du noyau 18, l'entrefer 22 diminue et l'effort antagoniste du ressort 36 augmente. La variation combinée de ces deux paramètres permet de garder le seuil de déclenchement électromagnétique sensiblement constant. Le réglage du noyau fixe 18 modifie essentiellement la caractéristique de déclenchement thermique du ressort 46 à mémoire de forme grâce à la variation de la précontrainte du ressort de rappel 36.In FIG. 2, the same reference numbers designate parts which are identical or similar to those in FIG. 1. The return spring 36 of the pusher 32 is supported on a collar 57 of the fixed core 18, the latter being formed by a self-tapping screw screwing into the sheath 14. The plunger core 20 has a hollow sleeve inside which houses the shape memory spring 46. The drive head of the pusher 32 bears directly on the spring 46 with shape memory. The operation of this trigger is similar to that described with reference to FIG. 1, except the trigger setting which is different. This adjustment is effected by screwing or unscrewing the fixed core 18 in the sheath 14 resulting in a combined variation of the length of the air gap 22 and of the opposing force of the return spring 36. In the event of the core 18 being unscrewed, the 'air gap 22 increases at the same time as the force of the return spring 36 decreases. Conversely, if the core 18 is screwed on, the air gap 22 decreases and the opposing force of the spring 36 increases. The combined variation of these two parameters keeps the electromagnetic trigger threshold substantially constant. The adjustment of the fixed core 18 essentially modifies the thermal triggering characteristic of the spring 46 with shape memory by virtue of the variation in the preload of the return spring 36.

L'agencement du ressort 46 à mémoire de forme à l'intérieur de l'espace 42 clos peut être différent de celui représenté aux fig. 1 et 2. Le même ressort 46 à mémoire de forme peut servir pour tous les calibres d'une gamme à condition d'utiliser une bobine 12 prédéterminée, dimensionnée à ampères-tours constant (ni = k, n étant le nombre de spires de la bobine, i le courant nominal, et k une constante). L'adoption de la bobine 12 appropriée permet de garder un échauffement constant dans l'espace 42 clos quel que soit le calibre choisi. Une gamme complète peut être ainsi réalisée en conservant toutes les pièces du déclencheur 10 à l'exception de la bobine 12.The arrangement of the spring 46 with shape memory inside the enclosed space 42 may be different from that shown in FIGS. 1 and 2. The same shape memory spring 46 can be used for all the calibers of a range provided that a predetermined coil 12 is used, dimensioned at constant ampere-turns (ni = k, n being the number of turns of the coil, i the nominal current, and k a constant). The adoption of the appropriate coil 12 makes it possible to keep constant heating in the enclosed space 42 whatever the caliber chosen. A full range can thus be produced by keeping all the parts of the trigger 10 with the exception of the coil 12.

Un organe de réglage, réalisé en un matériau de conductibilité thermique prédéterminé, est inséré entre la bobine 12 et le ressort 46 à mémoire de forme pour ajuster la constante de temps thermique dans l'espace 42.An adjustment member, made of a material of predetermined thermal conductivity, is inserted between the coil 12 and the spring 46 with shape memory to adjust the thermal time constant in space 42.

L'invention n'est bien entendu nullement limitée aux modes de mise en oeuvre plus particulièrement décrits et représentés aux dessins annexés, mais elle s'étend bien au contraire à toute variante restant dans le cadre des équivalences électrotechniques, notamment celle dans laquelle le noyau mobile 20 du déclencheur 10 serait dépourvu d'extracteur 24, ou celle dans laquelle une culasse auxiliaire en matériau magnétique serait agencée autour de la bobine 12.The invention is of course by no means limited to the modes of implementation more particularly described and represented in the appended drawings, but it extends quite the contrary to any variant remaining within the framework of electrotechnical equivalences, in particular that in which the core mobile 20 of trigger 10 would be without extractor 24, or that in which an auxiliary yoke of magnetic material would be arranged around the coil 12.

Claims (10)

1. Thermal-magnetic trip device with a mechanism (40) of an electric circuit breaker comprising :
- a stationary core (18) associated with a movable core (20) sliding by means of an air-gap (22),
- a tubular control coil (12) surrounding coaxially said stationary and movable cores (18, 20), the air-gap (22) being crossed by a magnetic flux due to the passage of the current in the coil (12),
- a spring (36) resetting the movable core (20) in spreaded position when the current intensity for excitation of the coil (12) is lower than the electromagnetic trip threshold,
- a thermomechanical sensor (44) of shape memory effect alloy, sensitive for the temperature rise of the control coil (12),
- and unlocking means cooperating with the movable core (20) and the thermomechanical sensor (44) to ensure the automatic tripping of the mechanism (40),

characterized by the fact that the thermomechanical sensor (44) of shape memory effect alloy comprises a helical spring (46) arranged in a closed space (42) insides the insulating duct (14) supporting the coil (12), and that the ampere-turn number of the coil (12) is constant for all sizes of a range.
2. Thermal-magnetic tripping device according to claim 1, characterized by the fact that the insulating duct (14) is constituted by a tubular sleeve closed at one of its ends by a bottom (16) and at the opposite end by the stationary core (18), and that the closed space (42) is arranged between the stationary core (18) and the bottom (16).
3. Thermal-magnetic tripping device according to claim 2, characterized by the fact that the shape memory effect spring (46) and the movable core (20) are arranged coaxially in said space (42) and cooperate with an unlocking slider (32) crossing axially the stationary core (18).
4. Thermal-magnetic tripping device according to claim 3, characterized by the fact that the reset spring (36) of the movable core (20) urges the slider (32) towards the inactive position of the trip device and constitutes at the same time a polarization element for the shape memory effect spring (46), the critical transformation temperature of which depends on the restoring force of the reset spring (36).
5. Thermal-magnetic tripping device according to claim 4, characterized by the fact that the shape memory effect spring (46) surrounds the movable core (20) bearing on the bottom (16) of the duct (14) and cooperating by its opposite end with a magnetic plate (48) able to move the slider (32) towards the active trip position by axial lengthening of the spring (46) after exceeding the critical temperature in the space (42) while the movable core (20) stays still in the spreaded position.
6. Thermal-magnetic tripping device according to claim 5, characterized by the fact that the magnetic plate (48) is in form of a bridge, one face of which is provided with a guiding lug (50) mounted axially sliding in a hole (52) of the movable core, and the other face of which cooperates with the unlocking slider (32).
7. Thermal-magnetic tripping device according to claim 4, characterized by the fact that the shape memory effect spring (46) is arranged insides the movable core (20) in shape of a hollow sleeve, and that the driving head of the slider (32) is directly in contact with the spring (46).
8. Thermal-magnetic tripping device according to claim 5 or 6, characterized by the fact that the reset spring (36) of the unlocking slider (32) is bearing on a screw (54) or ring, the axial position of which is adjustable in a screwed hole (56) of the stationary core (18) in order to adjust the pretension of the reset spring (36).
9. Thermal-magnetic tripping device according to claim 7, characterized by the fact that the reset spring (36) of the slider (32) bears on a flange (57) of the adjustable stationary core (18), this last named comprising an external threading which screws in the duct (14) for the adjustment of the axial air-gap (22) and the restoring force of the spring (36).
10. Thermal-magnetic tripping device according to one of claims 2 to 9, the movable core (20) being connected with an operating rod (24) of the movable contact arm (28), characterized by the fact that the bottom (16) of the duct (14) comprises an opening (26) for the passage of core (20) and rod (24), and that an adjustment element of predetermined thermal conductivity material is inserted between the coil (12) and the shape memory effect spring (46) in order to adjust the thermal time constant in the space (42).
EP84402508A 1983-12-26 1984-12-05 Thermal-magnetic tripping mechanism of a circuit breaker made of shape memory effect material Expired EP0147278B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT84402508T ATE31590T1 (en) 1983-12-26 1984-12-05 MAGNETOTHERMAL ACTUATOR MADE OF A SHAPED MEMORY EFFECT MATERIAL INCORPORATED IN A CIRCUIT BREAKER.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8320898A FR2557353B1 (en) 1983-12-26 1983-12-26 MAGNETOTHERMAL TRIGGER IN SHAPE MEMORY MATERIAL, ASSOCIATED WITH A CIRCUIT BREAKER MECHANISM
FR8320898 1983-12-26

Publications (3)

Publication Number Publication Date
EP0147278A2 EP0147278A2 (en) 1985-07-03
EP0147278A3 EP0147278A3 (en) 1985-08-21
EP0147278B1 true EP0147278B1 (en) 1987-12-23

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP84402508A Expired EP0147278B1 (en) 1983-12-26 1984-12-05 Thermal-magnetic tripping mechanism of a circuit breaker made of shape memory effect material

Country Status (4)

Country Link
EP (1) EP0147278B1 (en)
AT (1) ATE31590T1 (en)
DE (1) DE3468290D1 (en)
FR (1) FR2557353B1 (en)

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US7579935B2 (en) 2002-06-05 2009-08-25 Honda Giken Kogyo Kabushiki Kaisha Actuator
DE102012011063A1 (en) * 2012-06-04 2013-12-05 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Electrical switching device e.g. generator circuit breaker, has trip coil traversed by current to be monitored, and rod-shaped tripping armature made of material exhibiting thermal effect and magnetic shape memory effect

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DE4224046C2 (en) * 1992-07-21 1994-07-07 Elektroelement Izlake D D Overcurrent release for protective switching devices
DE9405745U1 (en) * 1994-03-09 1994-05-19 Siemens AG, 80333 München Overcurrent release
DE4413888B4 (en) * 1994-04-21 2004-09-02 Abb Patent Gmbh Overcurrent release for a self-switch
DE60032137T2 (en) * 2000-09-12 2007-10-11 Hager-Electro S.A.S. Circuit breaker with magnetothermic trip unit
IL157962A0 (en) 2001-04-26 2004-03-28 Swagelok Co Valve with snap connector
DE102004056280A1 (en) * 2004-11-22 2006-05-24 Abb Patent Gmbh Protective switch with magnetic release for e.g. motor or circuit protection, is made from alloy with magnetic shape memory
CN101425434B (en) * 2008-12-17 2011-05-18 王则旺 Shunt opening trip coil
JP6009340B2 (en) * 2012-12-12 2016-10-19 三菱電機株式会社 Circuit breaker and electromagnetic trip device
US9746044B1 (en) * 2016-04-15 2017-08-29 GM Global Technology Operations LLC Resettable sensor assembly and system
CN109243936B (en) * 2018-10-26 2024-07-12 厦门国研科技有限公司 Multi-loop circuit breaker
CN115220394A (en) * 2022-06-30 2022-10-21 江苏万力机械股份有限公司 Digit control machine tool with high sensitivity is automatic to be opened and stops function

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DE2139852A1 (en) * 1971-08-09 1973-02-15 Battelle Institut E V SWITCHING ELEMENT WITH TEMPERATURE-DEPENDENT SWITCHING POSITION
DE2646916A1 (en) * 1976-10-18 1978-04-20 Bbc Brown Boveri & Cie ELECTRICAL CIRCUIT BREAKER FOR OVERCURRENT AND SHORT CIRCUIT RELEASE
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DE3013016A1 (en) * 1980-04-03 1981-10-08 Brown, Boveri & Cie Ag, 6800 Mannheim RELEASE SYSTEM OF A SELF-SWITCH TO INTERRUPT A CIRCUIT

Cited By (2)

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Publication number Priority date Publication date Assignee Title
US7579935B2 (en) 2002-06-05 2009-08-25 Honda Giken Kogyo Kabushiki Kaisha Actuator
DE102012011063A1 (en) * 2012-06-04 2013-12-05 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Electrical switching device e.g. generator circuit breaker, has trip coil traversed by current to be monitored, and rod-shaped tripping armature made of material exhibiting thermal effect and magnetic shape memory effect

Also Published As

Publication number Publication date
ATE31590T1 (en) 1988-01-15
EP0147278A2 (en) 1985-07-03
DE3468290D1 (en) 1988-02-04
EP0147278A3 (en) 1985-08-21
FR2557353B1 (en) 1986-04-11
FR2557353A1 (en) 1985-06-28

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