MXPA00002669A - Electromagnetic actuator - Google Patents

Abstract

Electromagnetic actuator for moving a contact into a switched-on or switched-off state, comprising a contact-actuating rod which is displaceable in the longitudinal direction between a first position, corresponding to the switched-off state, and a second position, corresponding to the switched-on state. A core which is made of magnetizable material and interacts with a switch-on coil is attached to the contact-actuating rod. Also present is a pole piece which is made of magnetizable material and of which that face which is directed towards the core, in the first position of the contact-actuating rod, is arranged at an air-gap distance from that surface of the core which is directed perpendicular to the direction of displacement, and in the second position bears as closely as possible against the said core surface. The actuator furthermore comprises a yoke made of magnetizable material for closing the magnetic flux circuit of the switch-on coil through the pole piece and the core. A permanent magnet device is used to maintain the contact-actuating rod in the first position, while a spring preloads the contact-actuating rod, in its second position, towards the first position. The actuator is provided with a switch-off coil which, for the purpose of moving the contact-actuating rod from the second position to the first position, is excited in order to eliminate the magnetic field of the permanent magnet device at least temporarily, the magnetic flux circuit of the permanent magnet device being separate from that of the switch-on coil.

Description

ELECTROMAGNETIC ACTUATOR FIELD AND BACKGROUND OF THE INVENTION The invention relates to an electromagnetic actuator for moving a contact to a state connected by a switch or a switch-off state, which comprises a contact drive rod, which can be moved in the longitudinal direction between a first position, which corresponds to the state disconnected by means of a switch, and a second position, which corresponds to the state connected by a switch, a core, which. It is made of a magnetizable material and is attached to the contact rod of a contact, a switch-on coil, which interacts with the core, a pole piece, which is made of magnetizable material and of which, the face which is directed towards the core, in the first position of the contact drive rod, is arranged at an air distance from that surface of the core, which runs perpendicular to the direction "of the REF. : 33104 displacement and, in the second position, it is kept as close as possible against the surface of the core, a cylinder head, which is made of magnetizable material, to close the magnetic flux circuit of the switching coil by switch, through of the pole piece and the core, a permanent magneto device for holding the contact drive rod, in the first position and a spring that preloads the contact drive rod, in its second position, towards the first position. An actuator of this type is known from the British patent application GB-A-2,289, 374. There are a number of initial considerations that are important for electromagnetic actuators and have to do with the safety of commutation and life service of a vacuum interrupter used in intermediate voltage distribution networks: 1. The connection by means of a switch must take place quickly, in such a way as to limit the damage caused by the contact surfaces that are burned as a consequence of a discharge Disruptive 2. Maintenance of the switch-connected state must be achieved with a sufficiently high contact pressure because otherwise the resistance of the excessive contact would lead to dissipation between the contacts, which may cause them to be welded together. This occurs mainly under high short circuit currents. 3. The opening of the contacts must take place with a high level of impulse, to separate any contacts that have been welded together. 4. The opening of the contacts must also take place at high speed, to limit the degree to which the contact surfaces are burned as a result of the arc produced. 5. For reasons of operational reliability of the drive, it should be sought to keep the number of components as low as possible. The failure of a switch can usually be attributed to a faulty drive mechanism. 6. In order to be able to make maximum use of the available switching capacity, it is sometimes desirable to perform switch-off at a specific time in the current or voltage curve. In a three-phase system, this switching moment may differ for each phase, and the switching pattern may also vary each time, depending on the conditions.

In the past, the first five points to consider have been satisfied by mechanical systems that act on the basis of energy stored in springs. These systems also allow constant delay times to be achieved. However,. These drivers still fail on certain occasions. The British patent application mentioned above refers to a bistable actuator that operates with a set of permanent magnets, a coil and a spring. As soon as a current is fed to the coil, the contact moves to the closed state or connected by means of a switch. The field of the coil, generated by the current, is oriented in the same direction as the magnetic field of the permanent magnet. The total magnetic force causes easy excitation, and only little current is required to move the contacts to the switched-on state. In the switch-connected state, the spring is tightened and the drive rod is held in place by the permanent magnets. The field of the permanent magnets exerts a force on the driving rod which is greater than the force of the spring and is directed opposite to the force of the spring. As soon as the switch-connected state of the contacts is reached, the electric current through the coil can be interrupted. To move the contacts to the open state or disconnected by means of a switch, an impulse of electric current is fed to the coil, generating a field that is opposite to that of the permanent magnets. The force on the drive rod, generated by the field of the permanent magnets, is thus partially eliminated, in such a way that the driving rod, on the one hand, is compressed by the energy stored in the spring towards the position corresponding to the state disconnected by switch, and on the other hand, is still reduced to a certain degree by the residual force generated by the permanent magnets. Therefore, this known actuator does not satisfy the demands imposed by the inventor that switch disconnection must be fast. This can be attributed to the fact that the magnetic flux, when these contacts move towards the disconnected state by means of a switch, is reduced too slowly in the switch-connected state of the contacts. The time of connection by means of a switch, for an actuator, is defined as the time from the start of the excitation of the connection coil by means of a switch, to the point at which the actuator contacts by the actuator come into contact with each other. In the case of actuators to drive contacts that are suitable - for the switching of high energies, the switch-on time is very large and is not reproducible. Due to the high self-induction of the switch-on coil of the actuator, the current slowly rises to the maximum level that can be reached. If, during this increase in current, the actuating force of the actuator is large enough to overcome the opposite force that occurs in the disconnected state by a switch (as a result of, inter alia, friction, the switch-off spring, the temperature, etc.), the moving part of the actuator, ie the contact drive rod, begins to move. The moment in which this happens depends, inter alia, on the tolerances in current intensity and friction. The switch-on time, ie the time from which the current is switched by the switch and until the contacts actually close, is difficult to predict and therefore the switch-on time is variable and can not be reproduced.

DESCRIPTION OF THE INVENTION The object of the invention is to provide an actuator of the type mentioned in the preamble, in which the aforementioned problems are avoided and by which, inter alia, vacuum switches can be switched on or off, with a controlled time, by means of a switch. , in such a way that it is possible to disconnect by means of a switch the switches, very quickly, to connect, by means of a switch, the switches at a controlled moment, and if required, to maintain the vacuum interrupters in two stable states. This object is achieved according to a first aspect of the invention, in that a disconnection coil is present by means of a switch, which, for the purpose of moving the contact rod of the contact from the second position to the first position , it is excited to eliminate the magnetic field of the permanent magnet device, at least temporarily, and in which the magnetic flux circuit of the permanent magnet device is separated from that of the switching coil by means of a switch. Due to the fact that the magnetic circuit of the permanent magnet and the circuit of the switching coil are separated, the flow path of the permanent magnets can be shorter, so that smaller magnets will suffice, with the result that the size of the actuator can also be smaller. Due to the fact that the permanent magnets are smaller, their influence lasts for less time when they are disconnected, in such a way that a high speed of disconnection by means of a switch is reached. In addition, the aforementioned separation of the flow paths allows the switch coil to be used optimally. Furthermore, in the actuator according to the invention, a high retention energy is achieved in the switch-connected state. It should be noted that the international patent application WO 95/07542 describes a bistable electromagnetic actuator in which a permanent magnet, a moving core and two coils are used. This actuator also has the disadvantage that the magnetic flux always closes through the permanent magnet which acts as an air space for the fields of the coils. As a result, this known actuator is not sufficiently effective. Further improvements and embodiments of the first aspect of the invention are described in the claims. In addition, a second aspect of the invention relates to an electromagnetic actuator for moving a contact to a state connected by a switch or disconnected by a switch, which comprises a contact-de-energizing rod, which can be moved in the longitudinal direction between a first position, corresponding to the state disconnected by means of a switch, and a second position, corresponding to the state connected by means of a switch, a core which is made of magnetizable material and which is connected to the contact rod of the contact, a coil of connection by means of switch, which interacts with the core, a pole piece, which is made of magnetizable material and of which, the face that is directed towards the core, in the first position of the contact drive rod, is arranged at a distance of air from that surface of the core that runs perpendicular to the direction of displacement and, in the second position, it is kept as close as possible against the surface of the core, and a cylinder head which is made of magnetizable material, to close the magnetic flux circuit of the switching coil by means of a switch, through the Polar piece and the core, and is characterized by the fact that a fixing device acting on the contact rod of the contact is present, and moving towards the engaged state when the contact drive rod assumes the first position and that it is disengaged after a predetermined period after the instant in which a current is supplied to the connection coil by means of a switch, and the period is greater than the time of force formation on the contact drive rod, which is required to overcome the opposite force occurring in the first position of the contact drive rod. The invention is based on fixing the moving part, in particular the contact drive rod, of the actuator, in the first position, with the result that a current can be formed in the switching coil by means of a switch, present until the intensity of this current is sufficient for the movable part to begin to move immediately when the fixing device is disengaged. The instant in which the movement begins is not determined by the intensity of the current in the switching coil by means of a switch, but rather by the uncoupling of the fixing device. Further improvements and embodiments of the invention are described in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be explained in more detail later, with reference to the drawings, in which: Figure 1 shows a section along the axis of the actuator rod of the actuator, according to the invention, in the disconnected state by means of a switch, of the associated contact; Figure 2 shows a side view of this actuator in said state; Figure 3 shows a cross section through the actuator, in the state connected by switch; Y Figure 4 shows a side view of the actuator shown in Figure 3.

Figure 5 shows a section along the axis of the actuator rod of a mode of the actuator according to the invention, in the disconnected state by means of a switch, of the associated contact, and having an electromagnetic fastening device; Figure 6 shows a side view of the actuator shown in Figure 5, in said state; Figure 7 shows a cross-section through another embodiment of the actuator according to the invention, in the state connected by a switch and having a mechanical fixing device; Figure 8 shows a side view of the actuator shown in Figure 7; Y Figure 9 shows graphs of the switch-on current, of a known actuator and of an actuator according to the invention, as a function of time.

DESCRIPTION OF THE PREFERRED MODALITIES The embodiment of the actuator according to the invention, which is shown in the Figures, comprises a contact drive rod 1, which is capable of moving the contact 2 towards a closed or switch-on state (see Figure 4) and to an open or switch-off state (see Figure 2). For this purpose the contact drive rod is mounted in such a way that it can be moved in the longitudinal direction and can thus be moved between a first position corresponding to the disconnected state by means of a switch, of the contact 2, and a second position, which corresponds to the state connected via switch, of the contact 2. In this mode, contact 2 is accommodated in a device called "vacuum bottle". In addition, a spring 3 for the compression of the contact is present in the actuator, and this spring, in the switch-on state of the contact 2 (see Figure 4), is compressed, thus pressing the contact parts of the contact. 2 contact with each other, to obtain the desired contact pressure. Furthermore, this spring 3 for the contact compression, in its switch-connected state, of the contact 2, preloads the actuating rod 1 in the direction of its first position. A core 4, which interacts with a set of switching coils 5 by means of a switch, is connected to the contact drive rod 1. These coils 5 surround the core and a polar piece 6. The core and the pole piece are made of magnetizable material. In the first position, especially the disconnected state by switch, of the contact 2, shown in Figure 1, the surfaces of the core 4 and the pole piece 6 which are oriented towards each other, have an air distance di the same. When the actuator is to move from the disconnected state by means of a switch, the first position of the contact rod 1 of the contact, shown in Figure 1, to the state connected by a switch, the second position of the actuating rod 1 of the contact, which is shown in Figure 3, the set of coils 5 is excited for a short period, resulting in the core 4 moving towards the pole piece 6 until the mutually confronting surfaces, of this core and of the Polar piece 6 are as close as possible to each other. As a result, the preloaded spring 3 is additionally charged, as shown in Figure 4. Since the considerations of energy efficiency have led to the selection of a short duration of excitation, the driving rod has to be maintained in the second position against the force of spring 3 for contact compression. For this purpose, a permanent magnet device is provided which in the embodiment shown comprises the permanent magnets 7. The North-South direction of these permanent magnets runs in the direction transverse to the axis of the drive rod 1. These permanent magnets 7 interact with an armature 8, which, in the embodiment shown, comprises two armature elements 9 running transversely to the axis of the actuating rod and which are made of a magnetizable material. As shown in Figure 3, the driving rod is maintained in the switch-connected state, the second position of the driving rod 1, which is shown in Figure 3, by the attraction between the magnet 7 and the driving elements. armature 9. In Figure 3, the circuit II of the associated magnetic flux is indicated schematically by a solid line, and, for reasons of clarity, is only plotted for the permanent magnet 7 on the right side. The circuit of the magnetic flux of the coils 5 is indicated schematically only for the right side, by line I. The parts of the cylinder head, which will be described later, ensure that the circuits I and II of the magnetic flux are closed. It is clear that the magnetic flux circuits I, II of the switching coils 5, and the permanent magnet 7, respectively, are completely separated from one another. The permanent magnets are placed in such a way that their attractive force is negligible even when the air distance is less than 0.5 mm. As a result, they will not affect the movement of disconnection of the actuator. In contrast to the known actuators, the fastening system of the actuator according to the invention, which, in the embodiment to be used preferably, comprises the permanent magnets 7 and the reinforcement elements 9, is formed in such a way that the flow of the permanent magnets crosses twice an effective air distance (see flow circuit II). As a result, a retention energy that is as high as twice is achieved. When disconnected by means of a switch, the holding power per se has an adverse effect on the switch-off movement. However, in this design the double air distance means that the force exerted by the permanent magnets on the armature, when the disconnection by switch decreases very quickly as the air distance becomes greater, so that the adverse effect It disappears very quickly. The circuit I of the magnetic flux of the switching coils 5 passes through the core 4, the pole piece 6 and the cylinder heads 10. The permanent magnet device is also provided with flow guide elements 11, 12 which they guide the magnetic flux towards and through the armature element 9.Preferably the cylinder heads 10 and the flow guiding parts 11, 12 are produced as a single entity, in such a way that there is no longer any need for adjustment between the air distances di and d2. Furthermore, the core 4 and the reinforcement elements 9 comprise a single unit, and the core and the reinforcement element are connected on a connection piece 13. This connection piece 13 preferably has a smaller transverse dimension than that of the core 4. and that of the armature elements 9. The actuator is disconnected, by means of a switch, by the disconnection coil 14, which is placed in such a way that with the excitation, the magnetic field that is generated as a result opposes the magnetic field of the permanent magnets Excitement in the form of impulses is enough. The switch-off energy is provided by the release of the contact compression spring 3 and, if appropriate, by a disconnect spring, by additional switch.

In the embodiment shown, a shunt 15 is provided, by means of which the holding power of the holding system and the sensitivity of the tripping coil 6 can be affected by switch (see flow path III). It should also be noted that the existing actuators have a disconnection action, by means of a switch, excessively slow. This is a result of the compromises made between the efficient use of the magnetic circuits, the distances of air and the dispersing flow, as appropriate, the use of permanent magnets and the number of control coils. In the present these disadvantages are remedied. The advantages of the bistable electromagnetic actuator, according to the invention, are: 1. High retention energy in the state connected by means of a switch. 2. High disconnection speed by means of a switch. 3. Optimal use of the permanent magnet due to the separated magnetic circuits and the use of double air distance for the permanent magnetic circuit The second aspect of the invention is explained on the basis of the bistable actuator shown in Figures 5-8 It should be noted that the invention can be used in any type of actuator The mode of the actuator according to the invention, which shown in the Figures, it comprises a contact actuation rod 1 which is capable of moving contact 2 towards a closed or connected state by means of a switch (see Figure 8) and an open or disconnected state by means of a switch (see Figure 6). For this purpose, the contact drive rod is mounted in such a way that it can move in the longitudinal direction and thus be able to move between a first position, corresponding to the disconnected state by means of a switch, of the contact 2, and a second position. corresponding to the switch-connected state of the contact 2. In this mode, the contact 2 is arranged in a manner called "vacuum bottle". ío ".

In addition, a spring 3 for the compression of the contact is present in the actuator, and this spring, in the switch-connected state, of the contact 2 (see Figure 8), is compressed, thus pressing the contact pieces 2 against each other. others to obtain the desired contact pressure. In addition, this spring 3 for the contact compression, in this switch-connected state, of the contact 2, preloads the actuating rod 1 in the direction of its first position. A core 4, which interacts with a set of switch-on coils 5, is attached to the contact drive rod 1. These coils 5 surround the core and a polar piece 6. The core and the pole piece are made of magnetizable material. In the first position, especially the disconnected state by switch, of contact 2, which is shown in Figure 5, the surfaces of the core 4 and of the pole piece 6 which are oriented towards each other, have an air distance di between them. When the actuator is to be moved from the disconnected state by means of a switch, which is the first position of the contact drive rod 1, shown in Figure 5, to the state connected by a switch, which is the second position of the contact actuation rod 1, shown in Figure 7, the set of coils 5 is excited for a short period, with the result that the core 4 moves towards the pole piece 6 until the mutually confronting surfaces of this The core and the polar piece 6 are as close as possible, one against the other. As a result, the pre-charged spring 3 is additionally charged, as shown in Figure 8. Since the considerations in energy efficiency have led to the selection of a short duration of the excitation, the drive rod has to remain in the second position against the force of the contact compression spring 3. For this purpose, a permanent magnet device is provided, which in the embodiment shown comprises the permanent magnets 7. The North-South direction of these permanent magnets runs in the direction transverse to the axis of the actuating rod 1. These permanent magnets 7 l interact with an armature 8 which, in the embodiment shown, comprises two armature elements 9 running transversely to the axis of the drive rod and are made of magnetizable material. As shown in Figure 7, the driving rod is maintained in the switch-connected state, the second position of the driving rod 1, which is shown in Figure 7, by the attraction between the magnet 7 and the operating elements. armature 9. In Figure 7, the associated magnetic flux circuit II is schematically indicated by a solid line and, for reasons of clarity, is plotted only for the right permanent magnet 7. The magnetic flux circuit of the coils 5 is indicated schematically only on the right side, by line I. The parts of the cylinder head, which will be described later, ensure that magnetic flow circuits I and II are closed.

It is clear that the magnetic flux circuits I and II, the switching coils 5, and the permanent magnet 7, respectively, are completely separated one from the other. The permanent magnets are placed in such a way that their attractive force is negligible even with an air distance of less than 0.5 mm. As a result, they will not affect the switch-off movement of the actuator. In contrast to the known actuators, the fastening system of the actuator according to the invention, which, in the embodiment to be used preferably, comprises the permanent magnets 7 and the reinforcement elements 9, is formed in such a way that the flow of the permanent magnets crosses twice an effective air distance (see flow circuit II). As a result, a retention energy that is as high as twice is achieved. When it is disconnected, by means of a switch, the retention energy, per se, has an adverse effect on the disconnection movement. However, in this design the double air distance means the force exerted by the permanent magnets on the armature, when the disconnection by means of a switch decreases very rapidly, as the air distance becomes greater, in such a way that the adverse effect It disappears very quickly. The magnetic flux circuit I of the switching coils 5 passes through the core 4 of the pole piece 6 and the cylinder heads 10. The permanent magnet device is also provided with flow guide elements, 11, 12 which guide the magnetic flux to and through the armature element 9. Preferably the cylinder heads 10 and the flow guiding parts 11, 12 are produced as a single entity, such that there is no longer any need for adjustment between the air distances di and d2. Furthermore, the core 4 and the reinforcement elements 9 comprise a single unit, and the core and the reinforcement element are connected on a connection piece 13. This connection piece 13 preferably has a smaller transverse dimension than that of the core 4. and that of the armature elements 9. The actuator is disconnected, by means of a switch, by the disconnection coil 14, which is placed in such a way that with the excitation, the magnetic field that is generated as a result opposes the magnetic field of the permanent magnets Excitement in the form of impulses is enough. The switch-off energy is provided by the release of the contact spring 3 of the contact and, if appropriate, by a disconnect spring, by additional switch. In Figure 9, the current I of connection by switch of a known actuator, is plotted along the axis of the ordinates and the time t is plotted along the axis of the abscissa. At the same time, a voltage is connected to the terminals of the connecting coil and the connecting current through the switching coil is slowly raised as shown by the solid line, until the connecting current I switch in time ti, has reached the level Ii, level that is associated with the opposite force that has to be overcome, in the disconnected state by switch, of the actuator, to move this actuator to the state connected by means of a switch. At time ti, the connection movement by means of a switch, the contacts actuated by the actuator start, and these contacts only come into contact with one another at time t2. After time t2, the switch-on current I starts to rise again to the maximum level. The opposite force is dependent on factors such as, inter alia, the friction in the actuator, the disconnect spring thereof, and these factors are susceptible to variations, in particular under the influence of temperature. The above influences' can give rise to an opposite force corresponding to the level I2 of the switching current by means of a switch. If a voltage is supplied to the connection coil by means of a switch at time t0, the switching current will rise again as shown by the solid line and will then rise further as shown by the dotted line. At time t3, the level I2 will be reached, after which the connection movement by means of a switch is initiated by the actuator. At time t5, the contacts that are to be actuated by the actuator, come into contact with each other. The switch-on time, which is associated with current Ii, is therefore equal to t2-to, while in the case of level I2, the switch-on time is t5 - t0, so that the time Switch connection can vary and is not reproducible. In addition, the voltage associated with the switch-on current can vary, such that at a lower voltage the connection current I follows, as an example, the curve indicated by a dotted line. It can be observed from the graph that at the threshold level Ii the actuator starts its connection movement by means of a switch, at time t4, while at the threshold level I2 the connection movement by means of a switch starts at time t6. Therefore, it seems that the switch-on time of the actuator is also dependent, to a considerable degree, on the switch-on voltage. The relatively high variation in switch-on time, under small variations in the threshold level and / or the supply voltage for switching in the actuator, is reduced in accordance with the invention, by the fact that a device is used of fixing 16 acting on contact rod 1 of contact. This fixing device moves towards the fixed state when the actuating rod assumes the first position, which corresponds to the state disconnected by means of a switch, of the actuator. When the connecting voltage or current is connected, the fixing device 16 remains in the engaged state until a predetermined period has elapsed, from the instant in which the switching current was switched on by means of a switch. This period is greater than the time for forming the force on the contact drive rod, which is required to overcome the opposite force that occurs in the first position of the contact drive rod 1. In other words, the period is, for example, greater than t6 - t0, where time is the maximum time that can be expected under the cumulative effect of mutually reinforcing influences. The period can be adjusted as a function of the switch-on current, and preferably ends when the current through the switch-on coil has reached a level that is higher than the level required to overcome the opposite force that occurs in the first position of the contact drive rod 1. The start of the connection movement by means of a switch is therefore independent of the variable opposite force of the actuator in the state switched off by means of a switch. In another modality, this period has a fixed, independent duration, greater than t6 - t0. Where t is greater than you, I is greater, and therefore strength is. By comparison with the situation without fixing or coupling, a smaller connection coil is sufficient, because the connection coil is used in a better way. The behavior of the connection by means of a switch, when it is not fixed, can be observed in the right part of the curve of Figure 9, and the release impulse is emitted in uncle, where uncle is the unloading response time. of the connection by means of a switch. This response time is much shorter and more reproducible than the response time in the case of an actuator without disengagement. The switching moments t? 2 and t? 2 ', associated with the coils of the switch coil, which vary as a result of the tolerances, are much closer than t2 and t5 illustrating the switching moments without fixing. Figures 5 and 6 show the electromagnetic version of the fixing device 16, while Figures 7 and 8 illustrate a mechanical version of the fixing device 6. The fixing device 16 shown in Figures 5 and 6 comprises a permanent magnet 17 which it is placed in a fixed position, as indicated by the shaded area. In the position disconnected by means of a switch, shown in Figures 5 and 6, the armature element 9 bears against the polar plates 18, so that in this disconnected state, the magnetic circuit of the permanent magnet is closed through the plates. 18 and the reinforcement element 9. As a result, the reinforcement element 9 is held in place, as are the associated core 4 and the contact drive rod 1. The fastening device 16 is further provided with a coil 19 with a winding 20, and the core of the coil abuts against the polar plates 18. When a current is supplied to the switching coils 5 by means of a switch, the actuator is maintained in the state disconnected by means of a switch, shown in Figures 5 and 6, and therefore the contact drive rod 1, is maintained in its first position, and the contacts 2 driven by the contact rod of the contact 1 remain separated from each other . After the current is turned on, the current in the connected coils 5 is increased by a switch. The actuator, even if the opposite force were to be increased, will remain in the disconnected state by means of a switch, until, after a preselected period followed by the switching-on time of the switching current, a current is supplied to the winding 20 of the coil 19, and this current has a magnitude and direction such that the field of the permanent magnet 17 is eliminated. Then, under the influence of the switch-on current, for the switch-on coils 5, the contact drive rod 1 can be moved into a connection state in which the contact 2 is closed. The switch-connected state of the actuator, with the contact 2 closed, is shown in Figures 7 and 8. However, these figures show an actuator with a mechanical fastening device. The period of time is selected to be greater than the time of formation of the tension force of the actuator, in which the moving parts of the actuator begin to move. The duration of the period can be derived from the switching current by means of a switch or it can have a fixed value. The mechanical fastening device 16 shown in FIGS. 7 and 8 comprises two fastening elements which, in the first position of the contact drive rod, engage each other and keep the contact rod of the contact fixed in this position . A fastening element is formed, in the embodiment shown in FIGS. 7 and 8, by the pin 21 which is fixed to the reinforcement element 9. The other fastening element in that case is in the form of a fastening passer 22 which it can rotate around the bolt 23. This fastening pin 22 is preloaded, in the position shown, by the compression spring 24. The position of the fastening pin 22 can be changed by a control device which, in this case, is formed for him. auxiliary actuator 25 which is schematically illustrated, which may be a conventional low-energy electromagnetic actuator. When the actuator is moved to the disconnected state by a switch, by supplying a current to the disconnect coil 14, the pin 21 and the clamping pin 22 are coupled to each other, specifically by the free ends, in the form of a hook., of the pins. If a current is then supplied to the switch coils by switch, to connect the actuator, the coupling between the pins 21 and 22 is retained until a voltage or current is supplied to the auxiliary driver 25 to allow the pin 22 to turn to the right, in such a way that the pin 21 is released from the clamping pin 22. This mechanical design of the clamping device 16 also maintains the disconnected state by means of a switch, of the actuator, until a period that is greater than the time has passed. for forming the force in the contact drive rod 1, which is required to overcome the opposite force occurring in the first position of the contact drive rod 1. Also here, the time period may be derived from the current supplied to the switch coil by switch, or may have a fixed, independent value. The control current for the auxiliary actuator 25 or the winding 20 of the coil 19 could be derived by a comparator (not shown), and the switch-on current is supplied to an input of the comparator, while a reference current is supplied. to its other input, and the reference current is greater than the level required to overcome the opposite force in the first position of the contact drive rod 1. The control current for the auxiliary actuator 25 or the winding 20 of the coil 19, optionally after the amplification or processing, can then be supplied to the output of the comparator. In the mode having a fixed period of time, a time switch (not shown) having a predetermined, fixed period of time can be used, the length of which can be selected according to the considerations described above. The time switch starts to work when the switch-on current, for the connection coil, of the actuator is switched by a switch and the end of the time period can remain even after the moment in which the connection current has reached its maximum level.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects- to which it refers. Having described the invention as above, the content of the following is claimed as property:

Claims (19)

1. An electromagnetic actuator for moving a contact to a state connected by a switch or a state disconnected by a switch, comprising a contact drive rod, which can be moved in the longitudinal direction between a first position, corresponding to the state disconnected by means of a switch , and a second position, which corresponds to the state connected by a switch, a core, which is made of magnetizable material and which is connected to the contact rod of the contact, a coil of connection by means of a switch, which interacts with the core, a piece polar, which is made of magnetizable material and of which, the face which is directed towards the core, in the first position of the contact drive rod, is arranged at an air distance from the surface of the core running perpendicular to the the direction of displacement and, in the second position, it is supported so close to It is possible against the surface of the core, a cylinder head that is made of magnetizable material, to close the circuit of magnetic flux of the coil by means of a switch, through the pole piece and the core, a permanent magneto device to maintain the actuating rod of the contact in the second position, and a spring that preloads the contact rod of the contact, in its second position, towards the first position, characterized in that a disconnection coil is present by means of a switch, which, for the purpose moving the contact drive rod, from the second position to the first position, is excited to eliminate the magnetic field of the permanent magnet device, at least temporarily, and because the magnetic flux circuit of the permanent magnet device is separated from the of the connection coil by means of a switch.

2. The actuator according to claim 1, characterized in that the armature element, which runs transversely to the axis of the driving rod and is made of a magnetizable material, is connected to the contact drive rod and the permanent magnet device is provided with guiding elements of the flow, which guide the magnetic flux towards and through the armature element.

3. The actuator according to claim 1 or 2, characterized in that the permanent magnet device comprises at least one assembly that is arranged in such a way that the North-South direction thereof is transverse to the axis of the actuator rod of the actuator. contact, because the flow guiding elements are arranged on the side of the North Pole and on the South Pole side of the magnet, elements having surfaces running perpendicular to the axis of the contact rod of the contact, which, in the first position they remain at a distance of air from the reinforcement element and, in the second position, they are against the latter, and because the disconnection coil by means of a switch is placed in a plane perpendicular to the axis of the rod. actuation of the contact and on the side of the guide elements of the flow that is opposite the armature element, the inner surface of the disconnect coil The switch is aligned with the side of the permanent magnet facing the contact rod.

4. The actuator according to claim 2 or 3, characterized in that the cylinder heads of the switch-on coils and the flow guide elements of the permanent magnet device form a single unit.

5. The actuator according to the indication 2, 3 or 4, characterized in that the core and the reinforcement element consist of a single unit, the core and the reinforcement element are connected by means of a connection piece.

6. The actuator according to claim 5, characterized in that the connection piece has a transverse dimension smaller than the core and that the reinforcement element.

7. The actuator according to claim 4, 5 or 6, characterized in that, in the switch-connected state of the contact, the air distance between the core and the pole piece is minimal, but is not zero.

8. The actuator according to one of claims 2 to 7, characterized in that a magnetic shunt is placed in the magnetic flux circuit of the permanent magnet.

9. The actuator according to one of claims 1 to 5, characterized in that the spring is formed, at least partially, by the spring for contact compression.

10. An electromagnetic actuator for moving a contact to a state connected by a switch or a state disconnected by a switch, comprising a contact drive rod, which can be moved in the longitudinal direction between a first position, corresponding to the state disconnected by means of a switch , and a second position, which corresponds to the state connected by a switch, a core, which is made of magnetizable material and which is connected to the contact rod of the contact, a coil of connection by means of a switch, which interacts with the core, a piece polar, which is made of magnetizable material and of which, the face which is directed towards the core, in the first position of the contact drive rod, is arranged at an air distance from the surface of the core running perpendicular to the the direction of displacement and, in the second position, it is supported so close to It is possible against the surface of the core, a cylinder head made of magnetizable material, to close the magnetic flux circuit of the connection coil by means of a switch, through the pole piece and the core, characterized in that a coil is present. switch disconnection, which, for the purpose of moving the contact rod of contact, from the second position to the first position, is excited to eliminate the magnetic field of the permanent magnet device, at least temporarily, and because it is present a fixing device acting on the contact drive rod, moving towards the engaged state when the contact actuating rod assumes the first position and which disengages after a predetermined period after the instant in which it is supplied a current to the connection coil by means of a switch, a period that is greater than time of force formation on the contact drive rod, which is required to overcome the opposite force occurring in the first position of the contact drive rod.

11. The actuator according to claim 10, characterized in that the period ends when the current through the switch coil has reached a level higher than that which is required to overcome the opposite force that occurs in the first position of the dipstick. of contact activation.

12. The actuator according to claim 10 or 11, characterized in that the period of time has a fixed, independent duration.

13. The actuator according to claim 10, 11 or 12, characterized in that the fixing device comprises a permanent magnet which holds the contact drive rod in its first position, and a coil to eliminate the field of the permanent magnet.

14. The actuator according to claim 13, characterized in that a comparator is present, the connecting current of the switching coil by means of a switch, is supplied to an input thereof and a reference signal is supplied to the other input, and the output from it is coupled to the coil.

15. The actuator according to claim 13, characterized in that the coil is controlled by a time switch having a predetermined, fixed duration.

16. The actuator according to claim 10, 11 or 12, characterized in that the fixing device comprises the fixing elements which, in the first position of the contact drive rod, are coupled to each other and maintain the contact rod of contact fixed in this position, and because a control device is present which, after the period of time, decouples the fixing elements.

17. The actuator according to claim 13, characterized in that the control device is an electromagnetic auxiliary actuator.

18. The actuator according to claim 16 or 17, characterized in that a comparator is present, the switch-on current of the connecting coil, is supplied to an input thereof and a reference signal is supplied to the other input , and the output thereof is coupled to the control device.

19. The actuator according to the rei indication 16 or 17, characterized in that the control device is controlled by a time switch having a predetermined, fixed duration. i ELECTROMAGNETIC ACTUATOR SUMMARY OF THE INVENTION An electromagnetic actuator for moving a contact to a connected state 5 by means of a switch or a state disconnected by a switch, comprising a contact drive rod which can be displaced in the longitudinal direction between a first position, corresponding to the state 10 disconnected by means of a switch, and a second position, which corresponds to the state connected by means of a switch. A core that is made of magnetizable material and that interacts with a connecting coil through 15 switch, is attached to the contact drive rod. Also present is a pole piece that is made of magnetizable material and from which, the face that is directed towards the core, in the first The position of the contact drive rod is arranged at an air distance from the surface of the core which is directed perpendicularly to the direction of travel, and in the second position it remains 25 as close as possible against the surface - • » of the nucleus. The actuator further comprises a cylinder head made of magnetizable material to close the magnetic flux circuit of the switching coil by means of a switch, 5 through the pole piece and the core. A permanent magneto device is used to hold a contact drive rod in the first position, while a spring preloads the actuating rod 10 of the contact, - in its second position, towards the first position. The actuator is provided with a trip coil by means of a switch that, for the purpose of moving the contact rod of the contact, from the second one. 15 position to the first position, is excited to remove the magnetic field of the permanent magnet device, at least temporarily, the magnetic flux circuit of the permanent magnet device is separated from that of the 20 connection coil by means of a switch.