EP0566462A1 - Automatic circuit breaker - Google Patents

Abstract

This automatic circuit breaker comprises mechanisms which effect normal closing and normal opening of the circuit breaker, opening by thermal tripping, opening by magnetic tripping and opening by short-circuiting. The mechanism for normal closing and normal opening of the circuit breaker consists of a handle (M), a handle spring (14), a link rod (11), a moving contact (CM) and a multifunction mechanism spring (21), with tripping by the bearing of the free end of the link rod upon the bearing point (28) of the spring (21). The electromagnetic opening device has a fixed contact (CF) acting as a magnetic shell, the arrangement of which within this device makes it possible to obtain a magnetic tripping mechanism having no fixed core and no spring for positioning the moving core. <IMAGE>

Description

The present invention relates to an automatic circuit breaker which has a whole series of important advantages and important innovations compared to current circuit breakers used for identical or similar purposes.

More specifically, the invention relates to a circuit breaker mechanism having a breaking capacity by limiting the current.

Currently, and referring to the current state of the art, it must be noted that there are different types of circuit breakers, the large number of parts and an excessive functional complication result in high consumption and a large number of failures, as well as '' excessive cost.

To avoid these drawbacks, the applicant has invented a new type of circuit breaker whose simplicity of construction and operation considerably lowers the cost of this type of device at the same time as it guarantees an operation which presents significant technical improvements compared to circuit breakers. currently in use.

The automatic circuit breaker object of the present invention is essentially constituted by mechanisms which execute the normal closing and opening of the circuit breaker, opening by thermal tripping, opening by magnetic tripping and opening by short circuit.

The normal operating mechanism for setting and breaking the circuit breaker has the novelty of being formed of only five parts: handle, lever spring, connecting rod, mechanism spring and movable contact.

This configuration has the effect that the overall cost of the mechanism is much lower than that of current circuit breakers, which include, as appropriate, additional reset springs, a contact pressure spring, axes for rotating the parts, and d '' other additional parts, a ratchet, contact holders, etc.

The engagement of the mechanism of the normal functions of setting up and breaking the circuit breaker produced between the free end of the connecting rod and one end of the mechanism spring (fulcrum).

This engagement is composed of two pieces of metal wire in which the generators are parallel, the section of the two pieces can be arbitrary, cylindrical, square, rectangular, etc.

Likewise, provision has been made to incorporate into said mechanism a column which forms part of the lever.

By deforming and changing position, this column exerts pressure on the rod, developing a spring action thereon to maintain it in the pre-set position regardless of the mounting position of the switch.

The spring action is retained when the device establishment maneuver is initiated, then reappearing after the connecting rod has started to rest on the mechanism spring.

This interlocking and resetting system is unknown in current circuit breakers and its use makes it possible to integrate the interlocking function in rod-spring assemblies thereby reducing the number of parts and lowering the cost price.

The novelty of the electromagnetic opening device is that the fixed contact also performs the functions of a magnetic casing, by closing the magnetic circuit of the magnetic tripping mechanism. In addition, it is dimensioned, by its thickness, and by virtue of the housing provided for the coil, so that the windings of this coil are concentrated in the interval between the carcass and the movable core, which makes it possible to obtain a magnetic tripping mechanism without fixed core, thus bringing significant technical and economic advantages compared to current circuit breakers.

• de ressort de pression de contact, réalisée par des points d'appui sur le contact mobile et sur l'extrémité libre de la bielle ;
• de ressort d'ouverture du mécanisme, réalisée par les points d'appui sur la carcasse et le contact mobile ;
• d'enclenchement du mécanisme de coupure par ouverture thermique et/ou électromagnétique, par l'appui entre le ressort du mécanisme et l'extrémité libre de la bielle.

The mechanism spring included in the normal operating mechanism for setting and breaking the circuit breaker has the novelty that it alone performs the following functions:

• contact pressure spring, produced by support points on the movable contact and on the free end of the connecting rod;
• opening spring of the mechanism, produced by the support points on the carcass and the movable contact;
• for switching on the cut-off mechanism by thermal and / or electromagnetic opening, by pressing between the mechanism spring and the free end of the connecting rod.

In current circuit breakers, each of the functions mentioned is provided by a different part, and the interlocking is provided by two parts. In the usual construction this function is performed by at least four pieces.

The circuit breaker according to the invention comprises a striker which performs multiple functions which, in the case of current circuit breakers, are carried out by a greater number of parts, which implies a notable advantage, both in price and in simplicity of construction.

• dans le mécanisme d'ouverture électromagnétique, le percuteur retient le noyau mobile dans sa position de repos, sans exiger de ressort magnétique ;
• dans le mécanisme d'ouverture par déclenchement thermique, le percuteur transmet le mouvement du bimétal au corps principal du percuteur par l'intermédiaire d'un bras d'ouverture thermique.

The functions performed by the striker are as follows:

• in the electromagnetic opening mechanism, the striker retains the movable core in its rest position, without requiring a magnetic spring;
• in the thermal trigger opening mechanism, the striker transmits the movement of the bimetal to the main body of the striker via a thermal opening arm.

• les figures 1 et 2 sont deux schémas du disjoncteur, dans ses positions d'établissement et de coupure respectivement.

Other characteristics and advantages of the invention will be better understood on reading the description which will follow of an embodiment and in re referring to the attached drawings in which:

• Figures 1 and 2 are two diagrams of the circuit breaker, in its establishment and breaking positions respectively.

In the figures, it can be seen that the apparatus comprises a housing composed of a carcass 1 and a cover 2 made of insulating material, a set of elements constituting the system for interrupting the electric current, and which are actuated manually at using a lever M which emerges outside the housing, and a short-circuit extinguishing system 3 essentially formed by a chamber 4 for blowing the arc, and an arc track 5.

The electrical current interruption system is a mechanism which is made up of five kinematic chains.

The first chain A is formed of the lever M which rotates around an axis 10, which is part of the carcass 1, of a connecting rod 11, one end of which is threaded into a hole 12 made in the lever M and in which it can rotate freely, the other end being free, and a spring 14 for resetting the lever.

The second kinematic chain B is formed of the movable contact CM, which is a piece of conductive material which rotates around the axis 20, which is part of the carcass 1, and of a mechanism spring 21 having four support points , the first support point 28 (in the closed switch position shown in FIG. 1) being on the free end 13 of the connecting rod 11 and on the movable contact CM, a support point 22 on the contact mobile CM, and another fulcrum 27 on the carcass 1.

The third kinematic chain C is formed by a magnetic trip mechanism which responds electromagnetically to an excess of current in the circuit in which the circuit breaker is inserted. This chain is formed by a movable core 30 which slides inside a spool pin 31.

The fourth set D is composed of a bimetallic strip 40 which responds thermally to the excess current which passes through the circuit in which the circuit breaker is inserted, thus constituting the thermal trip system.

The last kinematic chain E is formed by the striker 50 made of a piece of insulating material which rotates around the axis 51, which is part of the carcass 1, and of a thermal rod 55. The striker has four main functional points : the magnetic opening point 52, the point of rotation of the thermal rod 55; the third functional point is the trigger arm 56 and, finally, the external trigger points 57.

• le disjoncteur étant dans l'état d'établissement (figure 1), le courant entre dans le disjoncteur à travers la borne d'entrée 60, montée sur la carcasse 1.

The operation of the main current circuit and the various mechanisms that make up the circuit breaker is as follows:

• the circuit breaker being in the state of establishment (FIG. 1), the current enters the circuit breaker through the input terminal 60, mounted on the carcass 1.

The electric current flows through the tongue 61, which is welded to one end 62 of the electromagnetic coil 32. From the coil 32, the current flows to the fixed contact CF through the contact pad 33. From the fixed contact CF, it passes in mobile contact CM through contact point 34. At this contact point, there can be two types of construction: one in which the fixed contact CF comes into direct contact with the mobile contact CM and another in which this contact is made via a contact pad 35.

From the movable contact CM, the current flows to the bimetal 40 through a braid 45 welded to the movable contact CM at one end and to the bimetal 40 at the other end.

The current reaches the output terminal 63 through the bimetal 40 and a second braid 42.

The different mechanisms that make up the circuit breaker correspond to five operating modes: normal closing of the circuit breaker, normal opening of the circuit breaker, opening by thermal tripping, opening by magnetic tripping, and opening by short circuit.

The normal circuit breaker establishment and breaking mechanism is formed by chains A and B.

Normal closing is carried out by turning the lever M from the cut-off position (figure 2) to the set position (figure 1). When the lever M is turned around the axis 10, this displaces the free end 13 of the connecting rod 11, which is acted upon by the flexible column 15 of the lever, until it comes into contact with the fulcrum 28 of the mechanism spring 21. Once the movement has started, the contact continues to push the end of the spring 28, pushing it through the end 13 of the connecting rod 11 and acting by the fulcrum 28 of the spring 21 on the movable contact CM; there is a rotation of this movable contact about the axis 20, so that the end 29 of the movable contact CM meets the fixed contact CF, establishing the electrical contact while, when we continue to turn the lever M until the end of its travel, defined by the free end of the connecting rod 13, this causes the spring 21 to bend, creating a contact pressure force at point 34.

Normal opening is carried out by turning the lever M from the setting position (figure 1) to the cut-off position (figure 2).

The normal cut-off mechanism is the same as that of establishment, and it is formed by the kinematic chains A and B.

Operation is the opposite of that described in the case of normal establishment.

Thermal trip opening occurs when excess current flows through the circuit breaker.

In this opening, the kinematic chains D and E intervene which form the thermal trigger mechanism which causes the opening of the cut-off mechanism formed by the chains A and B.

In normal operation, when a circuit breaker is closed, the current which passes through the bimetal 40 produces a gradual heating of the latter until it has reached a temperature of normal operating regime.

In the event of abnormal operation, in which there is an excess of current which passes through the circuit breaker and travels through the bimetal 40, there is a greater heating, which causes an additional displacement of the free end of the bimetal, which enters in contact with the thermal rod 55; this movement causes the striker 50 to rotate about the axis 51, which causes the trigger arm 56 to move, which in turn pushes the end 13 of the connecting rod 11, making it lose contact with the point support 28 of the mechanism spring 21 and it follows that the kinematic connection of the chains A and B is broken.

When the kinematic chain is broken, the two mechanisms return to their stable position, which corresponds to the cut-off state, under the effect of the mechanism spring 21.

When its point of contact 28 with the end of the connecting rod 13 is released, the spring 21 causes the movable contact CM to rotate about the axis 20 by relaxing the compression established in the body of the spring 25 during closing. The spring resets the handle 14, by turning the handle M to its cut-off position.

The opening by electromagnetic trip occurs in the presence of an excess of overcurrent in the main current circuit.

In this opening, the chains C and E intervene, which form the electromagnetic tripping mechanism and which cause the opening of the setting and breaking mechanism of the circuit breaker, which is formed by the chains A and B.

In normal operation, when the apparatus is in the establishment position (FIG. 1), the striker 50 maintains the movable core 30 in the normal operating position without the need for a spring.

Passing through the coil 32, the electric current generates a magnetic flux inside the circuit formed by the fixed contact CF (which acts as a magnetic carcass) and the movable core 30.

By crossing the mobile core 30, the magnetic flux creates in this core an electromagnetic force which tends to make it advance, sliding inside its guide 31 (coil axis) in the direction of the striker 50.

When there is an excess of current sufficient to set the movable core 30 in motion, it slides inside the guide 31, until it strikes the magnetic opening point 52, thereby rotating the striker 50 around the axis 51.

The rotation of the striker 50 causes the trip arm 56 to move, causing the contacts to open in the same way as in the opening by thermal trip.

In the case of a short circuit, there is an excess of intensity which is normally more than fifty times greater than the normal current, and it is much greater than the excess of overcurrent which was mentioned in the case of opening by electromagnetic release. In this case, the opening of the contacts, which occurs via the establishment and cutting mechanism A and B, which is the one which opens the contacts in the two opening modes described above, is not not fast enough for this type of fault.

In the case of an excess of current by short circuit, the force which pushes the movable core 30 is much greater than in the case of the opening by electromagnetic triggering. This force is transmitted to the striker 50, by rotating it on the axis 51. Through the trigger arm 56 of the striker 50, this rotation acts on the setting and breaking mechanism A and B of the circuit breaker in the same way than in the case of thermal and magnetic opening.

When the chains A and B have been released, the striker 50 continues to rotate, so that the extraction point 70 comes into contact with the movable contact CM, transmitting to it a pulse which makes it rotate around the axis 20.

This separation occurs before the instant when it would have occurred under the effect of the normal actuation of the establishment and cut-off mechanisms A and B.

Claims (4)

1. Automatic circuit breaker constituted by a mechanism which performs the normal closing and opening of the circuit breaker, opening by thermal tripping, opening by magnetic tripping and opening by short circuit, essentially characterized in that the mechanism which performs normal closing and opening of the circuit breaker is composed of a handle (M), a handle spring (14), a connecting rod (11), a mechanism spring (21) and a movable contact (CM), by engaging by pressing the free end of the connecting rod (11) on the bearing point (28) of the mechanism spring (21), and in that said engagement is constituted by two generatrices, parallel to each other, of two cylindrical bodies composed of pieces of metal wire or equivalent. 2. Automatic circuit breaker according to claim 1, characterized in that, in the mechanism which performs the normal closing and opening of the circuit breaker, a column (15) is provided which is part of the lever (M) and which, in the cut position is deformed by exerting a spring action on the connecting rod (11), maintaining the latter in the pre-setting position regardless of the mounting position of the switch, until the operation d establishment of the apparatus, the action disappearing after the connecting rod has started to rest on the mechanism spring (21). 3. Automatic circuit breaker according to claims 1 and 2, characterized in that, in the electromagnetic opening device, the fixed contact (CF) performs both the magnetic carcass functions, by closing the magnetic circuit of the magnetic tripping mechanism , and in that said fixed contact (CF) has been dimensioned so that, thanks to its thickness and to the housing provided for the coil (32), the windings of this coil are concentrated in the interval defined between the fixed contact ( CF) and the movable core (30), making it possible to obtain a magnetic tripping mechanism without a fixed core. 4. Automatic circuit breaker according to claims 1 to 3, characterized in that a striker (50) is provided which keeps the movable core (30) of the electromagnetic device in the normal operating position, thereby making it possible to obtain a mechanism for magnetic release without spring for positioning the moving core.

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