BE1007340A7 - High voltage breaker. - Google Patents

Abstract

High voltage gas circuit breaker, comprising extinguishing chambers similar to the type which has a compression piston, operating by actuation under a mixed principle of arc extinction, either by simple compression or by automatic blowing by thermal expansion and , in borderline cases of the actuation ranges of either principle, by combination of the two, the range of low to medium short-circuit currents being that in which the circuit breaker acts under the principle of the piston simple compression, while in the range of medium to high short-circuit currents it acts under the principle of automatic blowing by thermal expansion, automatically blocking by means of a suitable mechanism, during the opening operation, the contacts movable from its extinguishing chambers by forming a momentary fixed volume until the arc is interrupted and suitable for the operation of this principle, and following the principle in question. we.

Description

       

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   "High voltage circuit breaker" object of the invention
The present invention relates to a high voltage gas circuit breaker, comprising extinguishing chambers similar to the kind having a compression piston, however acting according to a mixed principle of arc interruption, either by simple compression or by blowing automatic by thermal expansion, and, in borderline cases, within the ranges of action of both principles, by combining the two. In the range of low to medium short-circuit currents, the circuit breaker, object of the invention, operates according to the principle of a simple compression piston.

   In the range of medium to high short-circuit currents, it acts on the principle of automatic blowing by thermal expansion, by automatically blocking during the disconnection operation the movable contacts of its extinguishing chambers, by means of an appropriate mechanism , by forming a fixed volume, momentary in there until the arc is interrupted, adapted to the functioning of this principle, these structural characteristics having been designed in order to achieve for this an optimal functional execution, especially during the disconnection operation and facing short-circuit currents inherent in this, and all this with a remarkably low energy level in the control mechanism used for its actuation and with a high extinguishing power for short-circuit currents high circuits,

   being more advantageous in that in the actuation range the principle of automatic blowing by expansion

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 thermal, the preliminary compression produced by the prior actuation of the piston type with simple compression allows that the filling pressure of the gas in the circuit-breaker chambers in question is significantly reduced, as regards the filling pressures necessary in circuit breakers working only on the principle of automatic blowing by thermal expansion or working on the principle of automatic blowing by thermal expansion with a mobile expansion volume and an auxiliary compression piston.



  Field of the invention
It is well known that in the field of high voltage circuit breakers which use a gas as a means of arc isolation and extinction, three separate solutions have been used to date, that is to say a piston of simple compression usually called "puffer", an automatic blowing by thermal expansion usually designated by "self blast" and an automatic blowing by thermal expansion with auxiliary compression piston.



   The puffer system, the most widely used today for medium and high voltages, although having significant advantages: concretely a simplicity both in terms of its operating principle and its construction, usual materials at low cost with a well-known behavior with regard to aging, great efficiency and regularity in extinguishing the entire range of short-circuit currents, very short arc times, largely the same at all levels of short-circuit, a low erosion at the nozzles and reduced wear at the arcing contacts, an ability to automatically adjust the pressure produced in the vacuum, in the event of wear of the nozzles under an accumulated extreme voltage of arcing,

   increasing automatically-

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 However, the disconnection speed and the low pressures of the insulating gas used, for example sulfur hexafluoride, have the fundamental problem that the necessary disconnection energy increases directly in proportion to the increase in short currents. -circuit. In fact, robust mechanical, pneumatic or hydraulic controls, of great power, are necessary for very strong short circuits, because in this principle the pressure of reheating and thermal expansion of the gas in the compression volume acts directly on the ordered.



   The self blast system, with fixed expansion volume, has been used to date only for medium voltages and, although its behavior is very good for very small currents, it requires a level of low energy, that it has a high extinguishing power in the maximum short-circuit currents and that, by using a coil for the rotation of the arc, its performances are improved at average levels at low intensity short circuit and wear of the contacts and nozzles is reduced, there is nevertheless a wide range of disadvantages which are mainly the following:

   a delicate principle requiring high construction precision, - expensive and sophisticated materials to reduce the erosion of the nozzles and communication grooves with the fixed volume of heating and expansion, because in this principle a sweeping and extinguishing for medium to low short-circuit currents are very sensitive to the wear of these elements since the thermal contribution of the arc to such levels is very low, - little accumulated experience of the behavior over time of the materials used,

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 variable arc times depending on the level of the short-circuit current, generally rather higher than those with a compression piston, high filling pressures of the extinguishing chambers with the blowing and insulating medium,

   which means that they must be dimensioned robustly, risk that the walls of the fixed heating and expansion container are metallized during a break in the medium to high level of short-circuit currents, since the volume expansion must be rather small, and beyond, the level of insulation under accumulated arc stresses can be reduced, increased cost of the principle in the case of using an arc rotation coil, and problems accumulated due to the difficulties that the switching of the circuit current to the coil involves, finally and compared to an automatic blowing by thermal expansion with mobile volume and auxiliary compression piston, this system provides an improved behavior at the levels of low to medium short circuits, compared to the principle of a simple automatic blowing,

   using an auxiliary compression piston for blowing this range of currents and for eliminating possible dielectric problems by metallization of the insulating walls due to deposits or projected metallic vapors, but this however poses a large number of problems who in turn actually understand the following:

   the moving mass is greatly increased, there are two separate volumes, one for thermal expansion, and another for compression, pressure relief valves with precise calibration are introduced so that at high levels of

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 short circuit with rapid increases in pressure in the volume of thermal expansion, the pressure which arises in the compression volume is evacuated through them towards the outlet, for the above reason, increase in energy required control, increased cost due to piston and auxiliary compression volume, plus three-chamber overpressure valves, and arc initiation times exceeding those of the puff system.



  Description of the invention
The high voltage circuit breaker, object of the invention, has all the advantages of a conventional circuit breaker of the "puffer" type, in the range of low to medium short-circuit currents, by operating in this field according to this principle, d where the problems of the other aforementioned principles are eliminated in this range of currents.



   From the range of medium to high short-circuit currents in which a puffer begins to experience difficulties (increase in the energy required for disconnection by producing, by heating and thermal expansion of the gas, high pressures in the volume compression), before the action of a critical short-circuit current it automatically blocks the movable contacts of the chambers, preventing their return movement, and simultaneously determines therein during the automatic blocking period an appropriate fixed volume so that the circuit breaker which has operated until then as a usual "puffer" automatically starts to function by automatic blowing by thermal expansion of the gas
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 contained in the same volumes,

   that is, as a "self blast" until the arc goes out

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 be completed, with the characteristic advantages of this principle in this range of short-circuit currents.



   Immediately after an arc extinction and the consequent release of the remaining pressure from the expansion volume, the movable contacts are automatically released, at the end of the cause which has produced this, and the complete circuit-breaker disconnection stroke is completed .



   As described above, the circuit breaker in question combines the advantages of the two operating principles, namely "puffer" and "self blast", without presenting any of their disadvantages, much more offering the advantage than in the field operating in "self blast", the prior compression due to the above actuation of the "puffer" type allows the filling pressure of the gas in the circuit breaker chambers to be significantly reduced compared to the filling pressures required in circuit breakers operating only on the principle of "self blast" or operating on the principle of "self blast" with a mobile expansion volume and an auxiliary compression piston.



   According to the characteristics of the invention, the mobile contacts of the circuit breaker, in addition to the usual connection and disconnection springs and other auxiliary elements, have been designed to include an automatic blocking engagement device so that, as soon as the movable contact has started the disconnection movement, it cannot in any case return to any point in the operation in which this tends to take place.



   More specifically, the circuit breaker has a structure like a "puffer" type circuit breaker, that is to say that it is provided with an extinguishing chamber in which is provided a membrane traversed by the movable contact and which determines a room with the

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 configuration of a guide cylinder in which the compression piston plays, also traversed by the movable contact and surrounded by a nozzle which moves jointly with the piston and the movable contact to surround the fixed contact, but with the exception that the contacts mobile above, and as mentioned above, are added to an automatic locking interlocking device which determines, also as mentioned above, that when the force corresponding to the pressure produced in the chambers by heating (thermal expansion)

   is greater than the instantaneous force communicated by the opening spring, the movable contact is automatically blocked by said automatic locking interlocking device, the movable contact being kept fixed and the circuit breaker now acting like a usual circuit breaker of the "self blast" type ", this situation being maintained until the arc is extinguished, the residual scanning pressure being immediately released when the movable contact completes its disconnection stroke, by means of the energy left in the opening spring (of logout).



   More specifically, and in order to achieve the above, the circuit breaker in question here has a structure based on a mechanical control mechanism based on a load shaft and on an output shaft connected to each other by a cam and by a transmission lever, the load shaft being controlled by the action of any suitable control element 1, for example a motor and gear unit or a crank, acting on the shaft by means of a mechanism appropriate coupling drive, to band the closing (connection) spring.

   in addition to the cam on which the closing spring acts, the load shaft is also equipped with a part, a pawl responsible for coordinating the position of one or more stop devices provided with

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 antagonistic springs so that, during the closing operation which includes the automatic bandage of the disconnecting spring, the springs allow the output shaft to rotate freely and, beyond, that the movable contacts of the extinguishing chambers move in a steering, freeing for this purpose the multiple steps of the automatic locking cam fixed on the output shaft and attached to a transmission which brings the movable contacts into contact with the opening spring.

   During an opening operation in which consequently the opening spring is now in operation, the pawl described above, without taking into account the position in which it is (closed or relaxed closing spring) allows the free movement of the stop device (s) on the automatic locking cam, sliding progressively over the active profile of the latter by which the movable contact moves in the direction of the opening movement, so that in the case of breaking a sufficiently high short-circuit current which may, due to the pressure produced by this in the compression volume, cause a tendency for the intervention of said movement,

   the movable contact is automatically blocked by the step of automatic blocking cam in which the active end of the stop device or one of the stop devices is at this time.



   To complete the above structure, the fixed and mobile contacts are housed in an extinguishing chamber which can in principle be declared similar to the "puffer" type, which has a membrane through which the mobile contact passes, a guide cylinder attached to said membrane, a piston which slides inside the guide cylinder and a nozzle in turn associated with the aforementioned piston.



   According to this structure and as mentioned above, with medium short-circuit currents at

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 high by which a pressure could be produced in a disconnection operation, by heating and by thermal expansion of the gas, being able to overcome the tension of the opening spring, the movable contact would be automatically blocked by the automatic blocking mechanism and the circuit breaker which would have worked until then as a "puffer" would now work as a "self blast", that is to say by an automatic blowing by thermal expansion until the arc is extinguished, determining by the action of said mechanism a predetermined volume in the compression chamber or, in other words, with the most ideal solution for these medium to high short-circuit currents.



   According to another simpler embodiment of the invention, the high-voltage circuit breaker is basically arranged from a mechanical control mechanism which has a single shaft for operating the circuit breaker and an energy accumulator, either mechanical, comprising a spring. or a set of springs either a duly adapted spiral spring or any other type of energy accumulator (hydraulic, hydropneumatic, etc.) capable of storing the energy necessary for the different operating cycles of the circuit breaker.



   The control shaft is provided with two blocks of elements, the first being intended to charge the energy accumulator and the second comprising the elements for engaging and releasing the circuit breaker, these blocks combined with the automatic blocking mechanism , working when appropriate, for the disconnection maneuver. These two blocks of elements are connected to each other by means of a suitable coupling which decouples them from one another when the energy accumulator is being charged and which secures them during one circuit breaker operation or cycles.

   The shaft is also provided with a lever which is integral with it (as a variant of other

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 elements such as cams) and which is connected via a transmission or other means of transmission with the movable contacts of the chamber.



   The charging block essentially comprises a cam which rotates on the control shaft and on which is wound a flexible transmission acting during the charging and discharging of the energy accumulator or of a system suitable in case any other kind energy accumulator is applied, a one-way radial coupling system, for example a free wheel, of another form called free-running coupling, associated with a ring gear intended to charge the energy accumulator by external means, automatically by means of a gearmotor assembly or manually by means of a crank, and an axial half coupling also in one direction, operating in a direction opposite to the previous one and connecting this block and the block automatic engagement, release and blocking, as mentioned above.



   The automatic engagement, release and blocking block is fixed to the control shaft, in the direction of rotation, by means of an appropriate coupling (key, knurling, etc.), can be moved axially freely and has a one-way axial half-coupling intended for its coupling with the load block during the operation of the circuit breaker, for this and in the direction of the load block it is permanently stressed by an elastic element. This block is further provided with a retaining cam which has two steps formed in one piece with it and is associated with an engagement and release mechanism for controlling the operation of the circuit breaker by external and usual means.

   On its external diameter and on the arc of rotation corresponding to the opening operation, the body of this block is provided with steps or multiple teeth attached to one or more stop devices

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 stressed by antagonistic springs or otherwise by the force of gravity, forming by their association an automatic blocking mechanism which automatically prevents any backward movement against the direction of rotation of the shaft in the opening operation and, consequently any tendency of inversion of the movement of the movable contacts of the chambers.



   The above axial coupling halves, which combine the load block and the retaining block, and the aforementioned elastic element, can be replaced by another element (for example another freewheel) or by duly arranged elements which fulfill such a function, and in this case, the circuit-breaker control shaft could be directly secured to the automatic engagement, release and blocking block.



   Thus, and in the case of a sufficiently high critical short-circuit current which may cause, due to the pressure produced by this in the compression volume, a tendency to reverse said movement, the movable contact would be automatically blocked by the step, of the automatic locking mechanism, positioned at this time at the active end of a stop device or one of the stop devices.



   To complete the above structure, the fixed and movable contacts are housed in an extinguishing chamber which could in principle be said to resemble the "puffer" type which has a membrane through which the movable contact passes, a guide cylinder attached to the diaphragm, a compression piston sliding in the guide cylinder, and a nozzle in turn attached to the piston.



   According to this structure and as mentioned above, in the case of medium to high short-circuit currents, by which could be produced in an opening operation, by reheating and by

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 thermal expansion of the gas, a pressure which can overcome the instantaneous force supplied by the energy accumulator, the movable contacts would be automatically blocked by the automatic blocking mechanism and the circuit breaker which had hitherto worked as a "puffer" would now work as a "self blast", that is to say by means of an automatic blowing by thermal expansion until producing the interruption (extinction) of the arc, when the aforementioned actuation of the mechanism determines a predetermined volume in the compression chamber,

   that is to say with the most ideal solution for these medium to high short-circuit currents.



   To complete the energy accumulator, depending on the object of the characteristics that the circuit breaker must meet, more specifically the use of other springs is also provided to complete the operation of the circuit breaker, either in the opening operation as acceleration spring either to obtain a balanced balance of energies between those necessary for closing and for opening, these springs being mounted for example in the real poles or the chambers of the circuit breaker, supporting the energy accumulator well for the closing operation.



   Finally and according to another practical embodiment of the invention, the means for automatically blocking the movable contact comprise a mechanical and pneumatic mechanism which, in addition to being directly mounted in the extinguishing chambers of the circuit breaker, is actuated automatically in the opening operation by the pressure increases in the compression volumes and by their thermal expansion and which allows, when appropriate, the blowing and the interruption of the arc by the mixed principle of compression and automatic blowing by thermal expansion of the insulating gas.

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   The automatic blocking mechanism mounted directly in the extinguishing chamber essentially comprises one or more units formed by a pneumatic piston actuated directly by the increase in pressure in the compression volume via a gas passage orifice, a stop device pivoting around its shaft, an opposing spring acting permanently against the pneumatic piston and multiple steps or teeth which are conveniently arranged on the guide tube of the movable contact and on which act, when it is appropriate, the aforementioned stop devices or units. With the exception of multiple steps, the other elements can be located in the base plate of the extinguishing chamber.



   The automatic blocking mechanism in question, when activated by the increase in pressure in the compression volume (pneumatic pressure greater than the force of the opposing spring), prevents any tendency to reverse the movement of the movable contacts of the chambers during the opening operation when the active end of one or more of the stop devices is automatically engaged in the corresponding step of the multiple steps of the guide tube, at the precise moment at which such a trend begins, and thereby the power of the circuit breaker operation control is successfully reduced to practically that required to accelerate the moving masses and to obtain precise operating speeds.



   In the event that this trend does not occur (medium to low short-circuit currents), the active end of the stop device (s) slides freely on the multi-step profile during the opening (disconnection) operation. .

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   The value of the overpressure in the compression volume, for the dimensioning and actuation of the automatic blocking mechanism, can be chosen from those produced by the idle movement of the movable contacts in the opening operation and those which are considered appropriate and which are produced from a given level of short-circuit current.



   During the closing operation, the above-mentioned mechanism remains inoperative, allowing the movable contacts to move freely in this operation provided that during this operation there is no increase in pressure in the compression volume of the chambers extinction and, beyond that, the automatic blocking mechanism is not activated.



   According to this structure and as mentioned above, in the case of medium to high critical short-circuit currents by which could be produced in an opening operation, in the compression volumes of the extinguishing chambers by heating and thermal expansion insulating gas used, pressures which can overcome the instantaneous voltage or force supplied by the circuit breaker control, the movable contacts would be automatically blocked by the automatic blocking mechanism and the circuit breaker which would have functioned until then as a "puffer" would now function as a "self blast", that is to say by automatic blowing by thermal expansion,

   in other words with the most ideal solution for these cases when the actuation of the mechanism determines in the compression chambers a predetermined fixed volume which is transient there until the arc interruption.



   Other details and particularities of the invention will emerge from the description of the drawings which are annexed to this specification and which illustrate,

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 by way of nonlimiting examples, a particular embodiment of the circuit breaker according to the invention.



  Description of the drawings
Figure 1 is a schematic view of a high voltage circuit breaker produced according to the object of the present invention and which appears in the disconnected position, with the closing (7) and opening (6) springs released.



   Figure 2 shows a partial detail of the previous figure, corresponding in this case to the position of the circuit breaker closed and with the opening spring (6) tensioned during the closing operation and maintained in the latching mechanism. opening and release (26) for opening the circuit breaker.



   FIG. 3 finally shows the assembly of FIG. 2 in an intermediate holding position in which the circuit breaker no longer functions as a "puffer" and begins to act as a "self blast" by soliciting a critical intensity of short- circuit in the medium to high range, acting by the principle object of this invention.



   FIG. 4 shows the ranges of possible curves of the disconnection movement under high short-circuit currents and the increases in pressure produced by them in the volume of compression and thermal expansion of the gas.



   Curve l: where the total stroke is greater than the holding range of the automatic locking mechanism.



   Curve II: where the total stroke meets the first retaining step of the automatic locking cam (5).



   Curve III: where the total stroke meets the last retaining step of the automatic locking cam (5).

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   The distance "C" determines the minimum optimal interruption and isolation distance from the separation of the contacts.



   Figures 5 and 6 show two variants of the deflector plate, the deflector plate being mounted in the chamber instead of being secured to the movable contact.



   FIG. 7 is a graph corresponding to a characteristic curve (TTR as a function of Icc) of the circuit breaker which is the subject of the present invention: curve A showing its advantage in comparison with two conventional circuit breakers of the same energy level for their respective commands, with the principles of operation of the "puffer" type on curve B and of the "self blast" type on curve C.



   FIG. 8 is a schematic view of an automatic high-voltage circuit breaker provided with the aforementioned automatic locking interlocking device constituting the essential basis of the invention, for realizing the mixed principle of interruption by simple compression and by automatic blowing by thermal expansion.



   Figure 9 is a graph corresponding to a characteristic curve (TTR as a function of Icc) of the circuit breaker of the figure above: curve A showing its advantages compared to two usual circuit breakers with the same energy level for their respective commands , with the operating principles of the "puffer" type on curve B and the "self blast" type on curve C.



   FIG. 10 is a schematic view of a high-voltage circuit breaker produced according to the variant in which the latter is equipped with a single control shaft (operating), in the control mechanism of the circuit breaker which is in the closed position and , in this case, with a spring loaded energy accumulator

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 and retained in the latching and releasing mechanism of the circuit breaker.



   FIG. 11 shows the assembly of FIG. 10 during an opening operation, in an intermediate automatic blocking position in which, by requesting a critical short-circuit intensity of the medium to high range, the circuit breaker abandons l actuation as "puffer" to begin to act as a "self blast", acting according to the principle object of the present invention.



   Figure 12 shows the assembly of the figure above while in this case in the open position of the circuit breaker with the energy accumulator bandaged and retained in the latching and release mechanism of the circuit breaker.



   Figure 13 shows the ranges of possible curves of the opening movement under short-circuit currents, in particular under high short-circuit currents, and the pressure increases produced by this in the compression volume and expansion thermal gas, depending on a given situation when the contacts of the extinguishing chambers are separated for symmetrical or asymmetrical currents. The distance "c" determines the minimum optimal arc extinction distance from the separation of the contacts. The angle ss corresponds to the travel of the movable contact to the first retaining step and the angle z corresponds to the position of the steps for the automatic blocking of the movable contacts.



   Figures 14 and 15 show two variants of extinguishing chamber in which the deflector plate is mounted in the chamber instead of being secured to the movable contact.



   Figure 16 is a graph showing a characteristic curve (TTR as a function of Icc) of the

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 circuit breaker object of the present invention: curve A showing its advantages in comparison with two usual circuit breakers of the same energy level of their respective controls, with the operating principles of the "puffer" type at curve B and "self blast" at curve C.



   FIG. 17 shows a schematic view of an extinguishing chamber of a high voltage circuit breaker produced according to the object of the present invention and which is in the position of the circuit breaker closed and with the automatic blocking mechanism at rest (inactive ).



   FIG. 18 shows the assembly of FIG. 17 during an opening operation, in an intermediate automatic blocking position in which, by requesting a critical short-circuit intensity of the medium to high range, the circuit breaker stops act as a "puffer" to begin to act as a "self blast" according to the principle advocated in the present invention. This automatic locking mechanism is controlled by the increase in pressure in the compression volume (306).



   Figure 19 shows the assembly of the figure above, in this case in accordance with the open position of the circuit breaker, the automatic locking mechanism being at rest.



   Figure 20 shows the ranges of possible curves for the disconnection movement under short-circuit currents, in particular under high short-circuit currents, and the pressure increases produced by this in the compression and expansion volume thermal of the gas, according to a given situation of the moment at which the contacts of the extinguishing chamber are separated by symmetrical or asymmetrical currents.



   The distance "C" determines the minimum optimal extinction and insulation distance between the

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 fixed and movable contacts from the separation of the contacts.



   FIG. 21 is a graph corresponding to a characteristic curve (TTR as a function of Icc) of the circuit breaker which is the subject of the present invention: curve A showing its advantages in comparison with two conventional circuit breakers of the same energy level of their respective controls, with the operating principles of
 EMI19.1
 type "puffer" on curve B and "self blast" on curve C.



   In the various figures, the same reference notations designate identical or analogous elements.



  Preferred embodiments of the invention according to the general principle of embodiment to which FIGS. 8 and 9 refer, the automatic circuit breaker is constructed with a movable contact 101 and a fixed contact 102, the first being assisted for example by a closing spring 103 and by an opening spring 104 or by any other mechanism for controlling the circuit breaker, shown completely diagrammatically in FIG. 8, and further as in a conventional circuit breaker of the "puffer" type with an extinguishing chamber 105, a membrane 106, a guide cylinder 107, a compression piston 108 and a deflector plate 109 attached to the movable contact 101, and a nozzle 110,

   the circuit breaker being essentially characterized in that it is equipped with an automatic locking interlocking device 111 suitably added to the movable contact 101 so that this device 111 determines that, as soon as the disconnection operation has started under a current of high short circuit, by the thermal effect of this it is produced in the compression volumes of the extinguishing chambers, by heating and by thermal expansion of the gas, an excessive pressure which can overcome the tension of the spring

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 opening 104, there cannot be a return movement of the movable contact which again tends towards the situation of connection with the fixed contact 102.



   In the case where this limiting situation occurs, the automatic blocking engagement device 111 automatically determines a blocking of the compression piston 108 by which at this moment a predetermined volume is formed between the guide cylinder 107, the movable contact 101, the chamber 105 and the membrane 106 and by that the circuit breaker as a whole begins to
 EMI20.1
 operate like a self blast with well-known efficiency for extinguishing large short-circuit currents.



   The efficiency of a high voltage automatic circuit breaker as described above can be clearly seen in Figure 9 in which curve B presents the characteristics of a "puffer" type circuit breaker whose efficiency drops for values high short-circuit intensities as can be observed by the fall of the curve shown, this critical zone being motivated by the need to use large forces or energies to obtain the disconnection of the circuit breaker during its operation;

   curve C is given for an automatic blow-out circuit breaker and can be considered to have the opposite effect, that is to say that the critical zone of the circuit breaker occurs at small short-circuit intensities, causing dielectric problems due to the insufficient thermal contribution of the arc, that is to say that the blowing and sweeping are insufficient;

   curve A is presented for a circuit breaker produced according to the subject of the invention, the range of medium to high short-circuit currents corresponding to the operating range of the automatic locking interlocking device, and it can be observed that curve A contains the advantages of the two systems which are

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 commonly used, no critical zone being present at high or low short-circuit intensities as is the case with the usual principles.



   FIG. 9 is a graph showing a characteristic curve (TTR as a function of Icc) of the circuit breaker which is the subject of the present invention, curve A showing its advantages in comparison with two conventional circuit breakers which have the same energy level of their respective controls, with the operating principles of the "puffer" type on curve B and of the "self blast" type on curve C, and with the benchmarks: a, optimal zone of the "puffer" principle; b, improvement in behavior of the "self blast" type by prior compression of the "puffer" type; c, optimal area of the "self blast" principle; d, critical zone: dielectric problems due to insufficient thermal contribution from the arc (insufficient arc blowing and sweeping); e, critical zone: limits due to the increased energy demand in the control = f (Icc2);

   f, hatched area, area of improvements using the invention in question; and g, operating zone of the automatic locking mechanism in question.



   A preferred embodiment of the invention is shown in Figures 1 to 7 which show the practical embodiment from a double shaft circuit breaker control mechanism.



   In the light of these figures and more particularly of Figure 1, it is clear that the high voltage circuit breaker object of the invention, and which is shown in this figure in the open position and with the closing springs 7 and opening 6 released, includes mechanical control based on a load shaft 1 and an output shaft 2.

   The load shaft 1 is suitably attached a pawl 3 which accompanies the shaft in its movements and which acts on the stop device 4 by lifting the latter,

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 immediately at the start of the connection operation, from an amplitude r of the radius of the automatic blocking cam 5, in turn fixed on the output shaft 2, to an amplitude greater than the radius R of the same cam 5 in order to cross the steps 24 of the same cam, the stop device 4 being designed to act or not, during the disconnection operation, on the cam 5 of automatic blocking depending on what it appears or not during this operation critical short-circuit currents.



   , The automatic blocking cam 5 which, as mentioned above, is integral with the output shaft 2 is adjoined by its end opposite the control end of the stop device 4, to a transmission 16 connecting the contact movable 17 to the opening spring 6, and to an engagement and release device 26 with which the cam forms a part.



   The movable contact 17, provided in a variant with a deflector plate 18 coupled to the latter, slides inside an extinguishing chamber 15 in which a membrane 22 is installed. The movable contact comprises a piston 20 which acts in a guide cylinder 21 constituting a kind of bush for the displacement of the compression piston 20 and of which for its part is integral the nozzle 19 through which the fixed contact 23 penetrates when the movable contact 17 approaches the latter in the closing operation.



   The circuit breaker is also provided, as mentioned above and as usual, with a closing spring 7 and an opening spring 6, a third spring 8 being provided and tending to cause the pivoting of the stop device 4 against the automatic locking cam 5 and against which the pawl 3 acts in a coordinated manner. The closing spring 7 in turn acts on a cam 9 whose movements are shown by the connected arrows and which have been shown in the

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 Figure 1 in the form of continuous lines in the relaxed state of the spring 7 and by broken lines in the banded state of the latter, starting position for a bandaging operation thereof.

   The cam 9 transmits by a transmission lever 10 the rotational movement from the load shaft 1 to the output shaft 2 during the closing operation. It can be seen that the closing spring 7, during the bandage operation thereof, passes through the upper dead center when it is positioned by the cam 9 and by the shaft 1, to be retained afterwards in this position by the action of usual interlocking elements which, once released by external means, allow the cam to act on the lever 10 and to the latter on the shaft 2 and thus to execute the operation of closing during which the opening spring 6 is automatically bandaged and is retained in this state by the device 26, Figure 2, upon completion of the closing operation.



   As is also usual, an action on the load shaft 1 to band the spring 7 can take place manually or by the crank 11 or be automatic with the assistance of a geared motor assembly 12 and 13 assisted by a mechanism 14 suitable drive and coupling.



   The rotary movement of the shaft 1 during the bandage operation of the closing spring 7 performs with it the rotation of the pawl 3 to be positioned, as shown in broken lines, on completion of the bandage operation, by remaining in the quasi contact or actuation position on the stop device (s) 4 so that, as soon as the shaft 1 has been released to execute a closing operation, from this position and the cam 9 acting on the lever 10 and from there starting the rotation of the shaft 2 and consequently the rotation of the automatic locking cam 5, the pawl 3 immediately acts on a

  <Desc / Clms Page number 24>

 angle smaller than the angle ô of rotation of the automatic locking cam 5 on the stop device (s) 4,

   raising their active ends 25 from a distance r or smaller radius of the automatic locking cam 5 to a distance greater than R, thereby exceeding its stepped zone corresponding to the angle, so that upon completion of the closing movement the stop device (s) 4 are free, their active ends 25 resting at the end of the arc delimited by an angle ss of the profile of the automatic locking cam'5, FIG. 2.



   The three aforementioned angles of the automatic locking cam 5, which correspond to the actuating arcs of the stop device or devices 4 and the operation of which has been described during the closing operation with the assistance of the pawl 3 in FIGS. 1 and 2, also delimit specific operating domains during the opening operation.

   Thus, and starting from the closed position in FIG. 2, as soon as the mechanism 26 has received an unlocking command, the opening operation begins during which, and at a predetermined moment in the rotation of the output shaft 2 corresponding to the angle ss, the mobile contact 17 and the fixed contact 23 are repaired by the action of the opening spring 6, the energy of which is dimensioned so that during the stroke of the angle a it is always greater than that which corresponds to the pressures which could be produced in the compression volume by heating and by thermal expansion, in the case of a cut of high short-circuit currents,

   and that by the dimension of the extinguishing chamber 15 there are limits in this zone to obtain a minimum value of this energy so that the active end 25 of the stop device 4 arrives safely at least at the first step retaining multiple steps 24 of the locking cam

  <Desc / Clms Page number 25>

 automatic 5 in its active angle, this angle determining the optimal separation of interruption and isolation between the contacts 17 and 23.



   In the case of medium to low short-circuit currents, the dimensioning of the energy of the opening spring 6 is sufficient to carry out the opening operation, the active end 25 of the stop device 4 sliding freely, safely and completely, along the active profile of the automatic locking cam 5, the circuit breaker in question acting in this range of currents according to the principle of the simple compression piston of the "puffer" type, with the advantages which are inherent therein and described above.



   Returning again in the event of high short-circuit currents, and the active end 25 of the stop device 4 reaching the multiple step area 24 of the automatic blocking cam 5, the stop device (s) continue to move on the successive steps so that, in the case where there is a tendency for a partial return of the movable contact 17 due to large increases in subsequent pressures in the compression volume of the extinguishing chamber 15, the movable contact is blocked exactly in the position in which it tends to start the return movement, preventing the latter from taking place to a greater or lesser extent, by the action of elements 4,5 and 8 and thereby circuit breaker is able to extinguish the arc by automatic blowing by thermal expansion,

   that is to say as if it were a circuit breaker of the "self blast" type since at this time a predetermined volume is formed between the elements 15, 19, 20, 21 and 22 of the extinguishing chamber, with all the advantages relating to its high breaking capacity also described above. In particular, the detail in Figure 3 shows this possibility, and more particularly the movable contact in the automatic locking position.

  <Desc / Clms Page number 26>

 



   When the arc is interrupted, the pressure in the compression and thermal expansion chamber decreases rapidly so that the energy stored in the connection spring 6 when the movable contact 17 is blocked automatically completes the complete stroke of the contact. mobile 17 corresponding to the angle s of the control profile of the automatic locking cam 5.



   The stop device 4 can in turn naturally include a number "n" of stop devices of different lengths so that, given an identical number "e" of retaining steps in the automatic locking cam 5, a better Positioning accuracy of the movable contact can be obtained. The number of steps of the automatic locking cam 5 can vary, depending on the case, from one to the required number.



   Ultimately, the goal is that the mechanical assembly comprising the elements 3, 4, 5 and 8 can be applied once or more times to obtain the degree of robustness necessary to block the movable contacts just when there is a tendency to reverse the movement during the opening operation.



   The first three figures show a device for engaging and releasing the circuit breaker, and indicated by the reference 26, responsible for fixing the position of the automatic blocking cam 5 when the circuit breaker is in the closed position and at the same time retaining the spring. opening 6 which was bandaged by the action of the cam 9 and the lever 10 during the closing operation.



   When the circuit breaker must open, it is sufficient to release this latching and releasing device so that the opening spring fulfills its mission by starting the opening and rotation of the automatic locking cam 5.

  <Desc / Clms Page number 27>

 



   The guide cylinder 21 is provided with a truncated cone-shaped projection at its mounting area of the chamber so that an angle a can vary from 0 to 900. The distance "D" from this guide cylinder can also be equal to or greater than the total stroke of the piston 20 coupled to the movable contact 17, FIG. 2a, or alternatively greater than the maximum interruption stroke, corresponding to the last retaining step provided in the direction of disconnection by combination of the elements 4 and 5, but less than the total travel of the movable contact so that in the case where the distance "D" is less than the total travel of this contact, an evacuation of the gases remaining from the arc interruption takes place instantaneously when it occurs in the subsequent displacement, after the arc has been interrupted,

   an exit zone between the piston 20 and the cone-shaped wall of the guide cylinder 21, FIG. 2b.



   It should be noted that the guide cylinder 21 which can be made of a conductive or insulating material protects the insulating walls of the chamber 15, and throughout the disconnection stroke, from metallizations, thermal shocks, etc.



   The deflector 18 shown in Figures 5 and 6 can also alternatively be fixedly mounted in the chamber 15. On the other hand, the deflector as shown in Figure 6 can be hollowed out so that the gases which pass through it and which act one end to the other of the volume of the enclosure delimited by the piston 20 of the movable contact 17, and the guide cylinder 21 and the base to which the latter is coupled and which is part of the extinguishing chamber 15 to produce optimal mixing and flow of fresh gas, compressed beforehand, with gases from the arc zone.



   It follows from the structure described above, first that the high voltage circuit breaker object of the invention combines the advantages of circuit breakers

  <Desc / Clms Page number 28>

 "puffer" and "self blast" type torers, although eliminating the problems of each of them, offering an extremely simple structure as regards both the control means and the arc interrupting means, by allowing the use of usual materials at low cost and low pressure in the insulating and blowing medium.



   It is therefore also possible to greatly reduce the energy required for the control and thereby obtain improved mechanical behavior.



   In the upper detail of FIG. 2 (FIG. 2b) we see the references h and k which respectively show the total stroke of the piston and that of the arc interruption.



   Finally, in Figure 4 are shown the opening displacement curves under different short-circuit currents. The upper curve (Figure 4a) shows the opening movement of the circuit breaker and the right margin of this curve represents the three operating angles of the automatic locking cam 5. During its opening stroke (from the connected position R) we start with the angle area ss of the cam 5, in which the contacts separate at a point S shown on the curve.

   In this zone, the energy communicated by the opening spring 6 is dimensioned so as to be greater than that caused by the pressures produced by compression and heating of the gas which may be present in the compression volume, because in this zone , by dimensioning a given value cannot be exceeded since maximum peaks of overpressure cannot appear there.



   Going to the curve area which corresponds to the angle 1 where the multiple steps of the cam 5 can be found, in the case where there is a critical short-circuit current for which the pressure

  <Desc / Clms Page number 29>

 produced, as mentioned above, in the compression volume could exceed the instantaneous value of the energy communicated by the opening spring 6 and beyond induce the reversal of the movement, the automatic blocking mechanism described above begins to to work.



   The distance limited by the angle y is the optimum separation distance between the contacts of the circuit breaker to cause an arc interruption.



   Finally, the curve zone which corresponds to the angle ô of the automatic locking cam 5 and into which the pressure of the extinguishing chamber has fallen due to the fact that the arc interruption has taken place, the spring opening 6 still has enough energy to completely complete the total stroke of the movable contact 17, Figure 4a curve I (to the so-called disconnected position T).



   It is also provided, as a variant, that the total stroke of the movable contact 17 ends when the opening stroke reaches either the end of the angle B or the end of the angle y which coincide respectively with the first or the last. retaining step of the automatic locking cam 5, in other words with the optimal interruption and isolation distances, FIG. 4a curve II and curve III respectively.



   The lower curves of this figure 4 (figure 4b and 4c) relate to the position or stroke of the contacts and the first (figure 4b) shows the pressure increases obtained in the compression volume under different short-circuit currents, showing that with maximum intensities the pressure increase is very high and falls when the value of the short-circuit intensity decreases (we find in Figure 4b in U the actuation pressure level, in V the area to 100% of asymmetric Isc, in W the area with symmetrical Isc between approximately 60%

  <Desc / Clms Page number 30>

 and 100% and in X the zone at Icc between 0 and approximately 60%).



   Finally, the sinusoidal curves (figure 4c) show the position of the short-circuit currents corresponding to the pressure curves above and which can be present in the circuit breaker until the interruption (Y: level of short-circuit currents Icc).



   FIG. 7 shows a graph corresponding to a characteristic curve (TTR as a function of Icc) of the circuit breaker which is the subject of the present invention: curve A which shows its advantages in comparison with two conventional circuit breakers which have the same energy level for their commands respective with the operating principles of the "puffer" type on curve B and of the "self blast" type on curve C, and with the benchmarks: a, optimal zone of the "puffer" principle; b, improvement of the "self blast" behavior by prior compression of the "puffer" type; c, optimal area of the "self blast" principle; d, critical zone: dielectric problems due to the insufficient thermal contribution of the arc (insufficient sweeping and arc blowing); e, critical zone: limits due to increased energy demand in the command = f (Icc2);

   f, (hatched area) areas for improvement by the use of the invention in question; and g, control zone of the automatic locking mechanism in question.



   Another possible preferred embodiment, made from a single-shaft circuit breaker control mechanism is shown in Figures 10 to 16. From these and in particular from Figure 10, one can see how the circuit breaker high voltage, object of the invention, which in this figure is shown in the connected position, with the energy accumulator 202 charged, includes a control

  <Desc / Clms Page number 31>

 mechanical based on a single shaft 201 for actuating the circuit breaker.



   The rotational movements of both the charging block 203, when charging the energy accumulator, and the shaft 201, for actuating the circuit breaker (opening, closing) are represented by the corresponding arrows "A" for the first and "B" for the second.



   The control shaft 201 is duly provided with two blocks of elements, one of which 203 is intended for charging the energy accumulator 202 and the other 204, which is provided with elements for engaging and releasing the circuit breaker 204.1, 204.2, 215, in turn associates these with an automatic blocking mechanism 204.3, 216 which is activated when appropriate, during the opening operation, if critical short-circuit currents appear or not during this operation .



   Said blocks of elements, of load 203 and of automatic engagement, release and blocking 204 of the circuit breaker 204 are connected to each other by an appropriate coupling 205 which uncouples them during a charging operation of the energy accumulator 202 and which in turn couples them via the radial coupling 201.1 to the control shaft 201 during the operation of the circuit breaker or during the cycles of operation of the circuit breaker.



   The control shaft 201 is equipped with a lever 206 (as a variant, other elements) which is integral with it and which connects it via a transmission 207 or alternatively by a more complex transmission system, to the movable contacts 208 of the extinguishing chambers.



   The movable contact 208, provided in a variant with a deflector 223 which is integral therewith, slides in an extinguishing chamber 218 in which is mounted a

  <Desc / Clms Page number 32>

 membrane 219. The movable contact comprises a piston 221 which acts in a guide cylinder 220 constituting a sort of jacket for sliding of said compression piston 221 to which is coupled in turn the nozzle 222 through which the fixed contact 217 penetrates when the contact mobile 208 is moved to the previous one in the closing operation.



   The load block 203 essentially comprises a cam 203.1 coupled to a cylindrical extension which rotates on the control shaft 201 and on which is wound a flexible transmission 209 which acts during the charging or discharging of the energy accumulator 202, a one-way radial coupling system 210 associated with a toothed ring 211, the latter two being intended to charge the energy accumulator by conventional external means, automatically by means of a geared motor assembly or manually by means of 'A crank and a half coupling 205 axial also in a direction acting in the opposite direction from the previous 210, connecting this block to the block of engagement, release and automatic blocking of the circuit breaker 204 as mentioned above.



   The automatic engagement, release and blocking block 204 is fixed to the control shaft 201 in the direction of rotation, by means of a suitable coupling 201.1, it can move freely in the axial direction and has a half one-way axial coupling 205 intended for its coupling to the load block 203 during the operation of the circuit breaker, and for this purpose and in the direction of the load block it is permanently biased by an elastic element 214. This block also includes a cam retaining two steps 204.1 and 204.2 which is coupled to it and which in turn is associated with a latching and release mechanism 215 to control the operation of the circuit breaker by usual external means.

   On its external diameter and on the arc

  <Desc / Clms Page number 33>

 of rotation corresponding to the disconnection operation the body of this block is subdivided into two angles except 7, with a step at the beginning of the two angles, and it comprises steps or multiple teeth on the arc corresponding to the angle y in 204.3 associated in turn with one or more stop devices 216 biased by antagonistic springs, such elements forming in association an automatic blocking mechanism automatically preventing any return movement in the opposite direction to the rotation of the shaft in the opening operation and, beyond, any tendency to reverse the movement of the movable contacts of the chambers during their maximum interruption stroke.



   The angles ss and y mentioned above, of the engagement, release and automatic blocking block 204, which correspond to the sliding and operating arcs of the automatic blocking device or devices 216 delimit actuation areas specific during the circuit breaker opening operation.

   Thus, and starting from the closed position, in FIG. 10 as soon as the mechanism 215 has received a release command, the opening operation is started during which, and at a predetermined moment in the rotation of the control shaft 201 corresponding to the angle ss, the movable contact 208 is separated from the fixed contact 217 by the action of the force supplied by the energy accumulator 202 whose energy corresponding to this operation is dimensioned so that during the stroke of the angle ss, in addition to that necessary to reach the required disconnection speed, it is always greater than that which corresponds to the pressures which could be produced in the compression volume by heating and by thermal expansion of the gas,

   in the case of a cut of high short-circuit currents, and that by the dimensions of the extinguishing chamber 218 there are limits in this

  <Desc / Clms Page number 34>

 zone for obtaining a minimum value of this energy so that the active end of the automatic blocking stop device 216 safely reaches at least the first retaining step of the multiple steps 204.3 of the block 204 arranged in the angle y, this first step determining a stroke of the movable contact 208 equal to or greater than the distance "C", FIG. 13, which in turn determines the optimum minimum extinction separation between the contacts 208 and 217.



   In the case of medium to low short-circuit currents, the previous energy sizing of the energy accumulator 202, corresponding to the opening operation, is sufficient to safely and completely carry out this operation (by doing freely slide the control end of the automatic locking stop device 216 on the multiple steps 204.3 of block 204), the circuit breaker in question acting in this range of currents under the principle of the simple compression piston of the "puffer" type with the advantages inherent therein and described above.



   Returning to the case of high short-circuit currents and as soon as the active end of the automatic blocking stop device 216 has arrived in the area of the multiple steps 204.3 of the block 204, the stop device (s) continue to move on the successive steps so that in the case where there is a tendency of a partial return movement for the movable contact 208 due to large subsequent increases in pressure in the compression volume of the extinguishing chamber 218, the movable contact is locked exactly in the position in which it tends to begin this return movement, preventing by the action of the elements 204,204.

   3 and 216 that the latter takes place to a greater or lesser extent, after which the circuit breaker is able to extinguish the arc

  <Desc / Clms Page number 35>

 by automatic blowing by thermal expansion, that is to say as if it were a circuit breaker of the "self blast" type, insofar as at this moment a predetermined volume is formed between the elements 218,208, 219, 220,221 and 222 of the extinguishing chamber, with all the advantages relating to its high breaking capacity and also described above. In particular, the detail in FIG. 11 shows this possibility, and more particularly the movable contact in the automatic locking position.



   When the arc is interrupted, the pressure in the compression and thermal expansion volume drops quickly so that the energy stored in the energy accumulator 202 when the movable contact 208 is automatically blocked completes the complete stroke. disconnection thereof, until the cam 204.1 is engaged in the engagement and release mechanism 215, the circuit breaker remaining accordingly in the open position, ready for a subsequent closing operation.



   The stop device 216 can in its turn naturally be composed of a number "n" of stop devices of different lengths so that, given an identical number "e" of retaining steps in the multiple steps 204.3 of block 204 , better positioning accuracy e / n of the movable contact can be obtained. The number of steps in arc 1 corresponding to steps 204.3 may vary from one to as many as any number that is required and that can be arranged on the same variable arc.



   The above-mentioned automatic locking mechanism, i.e. the multiple steps 204.3 and the automatic locking stop devices 216, can be located anywhere in the system which transmits the movement of the shaft switch 201 from the circuit breaker to the movable contacts 208 of the chambers

  <Desc / Clms Page number 36>

 218, even on the movable contacts themselves, as shown in Figure 10c, with the corresponding link 224 for its actuation from the control shaft 201. In addition, the arrangement of said elements can, in depending on their position, be internal or external to the extinguishing chambers 218 or be a combination of the two arrangements.



   When the circuit breaker must be connected, FIG. 12, it is sufficient to act on the latching and release mechanism 215 shown diagrammatically, so that, the closing cam 204.1 being released, the energy accumulator 202 provides energy required for this operation through the control shaft 201 until completion of the turn corresponding to this operation, the mechanism 215 being again automatically engaged in the cam 204.2 at the end, the circuit breaker remaining in consequently in the closed position and ready for a subsequent opening operation.



   The guide cylinder 220 is provided with a frustoconical extension in its zone of mounting on the chamber, so that the angle a can vary from 0 to 900.



  The distance "D" of this guide cylinder can also be equal to or greater than the total stroke of the piston 221 coupled to the movable contact 208, FIG. 10a, or as a variant be greater than the maximum interruption stroke, corresponding to the last step of retainer provided in the disconnection direction in zone 204.3 of block 204, but less than the total travel of the movable contact, so that in the case where the distance "D" is less than the total travel of this contact, evacuation of the gases remaining from the arc interruption take place instantaneously when in the next movement, after the arc interruption, an outlet zone between the piston 221 and the cone-shaped wall of the guide cylinder 220 is produced, figure lOb.

  <Desc / Clms Page number 37>

 



   It should be noted that the guide cylinder 220 which can be made of a conductive or insulating material protects the insulating walls of the chamber 218, and from one end to the other of the disconnection stroke, of metallizations, of thermal shocks, etc.



   The deflector 223 shown in Figures 14 and 15 can also alternatively be fixedly mounted in the chamber 218. On the other hand, this deflector, as shown in Figure 15, can be hollowed out so that the gases pass through it and act in all the volume of the enclosure delimited by the piston 221 of the movable contact 208 and by the guide cylinder 220 and the base to which the latter is coupled to form part of the extinguishing chamber 218, in order to achieve mixing and flow optimal fresh gas, compressed beforehand, with gases from the arc zone.



   It follows from the structure described above, first that the high voltage circuit breaker object of the invention combines the advantages of circuit breakers of the type "puffer" and type "self blast", while eliminating the problems of each d 'them, by allowing an extremely simple structure, as regards both the control means and the arc interrupting means, by allowing the use of usual materials of low cost and low pressure in the medium of insulation and blowing.



   It is therefore also possible to greatly reduce the energy required for the control and consequently obtain better mechanical behavior.



   The detail in FIG. 10b marked with the respective references h and k shows the total strokes of the piston and the maximum of the arc interruption.



   Finally, Figure 13 highlights the curves of the opening movement under different short-circuit currents. The curve shown in

  <Desc / Clms Page number 38>

 upper part (FIG. 13a) shows the opening movement of the circuit breaker, the right margin representing there the two operating angles of the engagement and release block 204. During this disconnection stroke, we meet the area of the angle ss in which the contacts are separated at a point S shown on said curve.

   In this zone, the energy communicated by the energy accumulator 202 is dimensioned so as to be greater than that which is caused by the pressures produced by compression and heating of the gas which may be present in the compression volume because, in this zone, by the dimensions of the extinction zone of the chamber, a given value cannot be exceeded insofar as maximum peaks of overpressure cannot appear there.



   Passing through the area of the curve which corresponds to the angle 1 where the multiple steps 204.3 of the engagement and release block 204 meet, in the case where there is a critical short-circuit current for which the pressure produced, as mentioned above, in the compression volume can exceed the instantaneous value of the energy communicated by the energy accumulator 202 and, beyond, induce the reversal of the movement, the automatic blocking mechanism described above on it would start to work.



  The distance "C" from the separation of the contacts is the minimum optimum separation distance between the contacts of the circuit breaker to carry out the arc interruption.



   In the area of the curve which corresponds to the angle 1 of block 204 and from the step at which an automatic blocking would take place, at the interruption of the arc by automatic blowing the pressure in the extinguishing chamber decreases rapidly in allowing the energy remaining in the energy accumulator 202

  <Desc / Clms Page number 39>

 Completely completes the total travel of the movable contact 208, Figure 13.



   The lower curves (FIG. 13b and FIG. 13c) of this FIG. 13 relate to the position or stroke of the contacts and the first (FIG. 13b) shows the increases in pressures obtained in the compression volume under different short-circuit currents, in showing that with maximum intensities the pressure increase is very high and falls when the value of the short-circuit intensity decreases (W and X).



   Finally, the sinusoidal curves (Figure 13c) show the position of short-circuit currents which correspond to the above pressure curves and which may be present through the circuit breaker until their interruption.



   FIG. 16 represents a graph corresponding to a characteristic curve (TTR as a function of Icc) of the circuit breaker which is the subject of the present invention, curve A showing its advantages in comparison with two conventional circuit breakers which have the same energy level of their respective controls , with the operating principles of the "puffer" type on curve B and of the "self blast" type on curve C, and with the benchmarks: a, optimal area of the "puffer" principle; b, improvement in behavior of the "self blast" type by prior compression of the "puffer" type; c, optimal area of the "self blast" principle; d, critical zone: dielectric problems due to insufficient thermal contribution from the arc (insufficient arc blowing and sweeping); e, critical area:

   limits due to increased energy demand in the control = f (Icc2); f, hatched area, area of improvements using the invention in question; and g, operating zone of the automatic blocking mechanism in question for the movable contacts.

  <Desc / Clms Page number 40>

 



   A third preferred and practical embodiment is shown in Figures 17 to 21; in the light of these figures, and more particularly of figure 17, it can be seen that the extinguishing chamber 301 of the high voltage circuit breaker object of the invention, and one of which is shown schematically in this figure in the "closed" position ", basically includes a gas-tight insulating container subjected to a given filling pressure with the insulating gas used (for example SF6). One of its ends is provided with fixed contact 302 coupled to a connection terminal. Opposite towards the front is arranged the whole of the movable contact 303. This movable contact is essentially composed of a guide tube with incorporated contact fingers, a nozzle 304 and a compression piston 305 , all mated to each other.

   The assembly of the movable contact 303 is in turn housed in a guide cylinder 315 coupled to a base plate 316 of which a second connection terminal projects and is electrically connected to the base plate by means of sliding contacts which are not not shown. The elements: movable contact 303, guide cylinder 315 and base plate 316 compose a volume of thermal expansion and compression 306. On the base plate and associated with it, there is a membrane 37 intended to hermetically seal. the volume of thermal expansion and compression 306 during the opening operation and allowing the flow of insulating gas to fill said volume during the closing operation.

   The chambers are further supplemented by earth insulators 317, also in the same gas-tight manner, subjected to the same filling pressure of insulating gas from the chambers because they are directly connected to it. Inside the earth isolators 317 are arranged the transmission bars 313 and the levers connecting the contacts

  <Desc / Clms Page number 41>

 mobile 303 and the circuit breaker control mechanism 314 not shown in the figure.



   In addition, and as the basis of the present invention, the extinguishing chamber 301 is provided with an automatic automatic locking mechanism 309,310,311,312 acting in the opening operation by allowing when appropriate, a blowing and an interruption. arc by the combination of compression and automatic blowing by thermal expansion of the insulating gas, object of the present invention.



   The automatic blocking mechanism, mounted directly in the extinguishing chamber 301, essentially comprises one or more assemblies made up of the following elements: a pneumatic control piston 309 located in the base plate 316 and whose active surface is directly connected through the holes 308 at the compression volume 306. The piston in turn acts by means of a rod on one of the ends of a stop device 310 pivoting around its shaft and which in turn is fixed in an extension in the form of a chassis for the base plate 316.

   On the opposite face of the aforementioned end of the stop device 310, an opposing spring 311 also supported on the extension of the base plate 316 acts permanently against the stop device 310 and in turn against the piston 309 maintaining them in the position shown in Figure 17. Finally, the guide tube of the movable contact 303 is provided with multiple teeth or steps 312 forming together with the elements mentioned above the automatic locking mechanism.



   The distances marked in FIG. 17 and in FIG. 20, M, N, L, C and 0 delimit specific fields of action of the automatic blocking mechanism 309,310, 311,312 during the opening operation of the circuit breaker. As mentioned above, the automatic blocking mechanism is controlled by the overpressure

  <Desc / Clms Page number 42>

 produced during the disconnection operation in the compression volume 306, through the holes 308, on the surface of the actuating piston 309 and against the opposing spring 311 so that the automatic blocking stop device pivots and presses its active end 318 on the surface of the guide tube of the movable contact 303, thus being ready to fulfill its automatic blocking function.

   This mechanism is dimensioned so that each pivoting of the stop device 310 takes place during the stroke M or up to a maximum of two thirds of the stroke N.



   Thus, and starting from the connection position, FIG. 17, as soon as the disconnection member of the circuit breaker control mechanism 314 has received a release command, the disconnection operation begins and consequently compression of the gas contained in compression volume 306.

   During the disconnection movement, at the end of the stroke M, the movable contact 303 is separated from the fixed contact 302 by the action of the energy supplied by the circuit breaker control mechanism 314 whose energy for this operation is dimensioned so that during the course of the course N, in addition to that which is required to reach the necessary speed, the energy is always greater than that which corresponds to the pressures which could be produced in the compression volume 306 by reheating and by thermal expansion of the gas, in the event of a cut of high short-circuit currents, and which are limited, by the dimensions of the elements of the extinguishing chamber 301, in this zone to obtain a minimum value of this energy,

   so that the active end 318 of the automatic blocking stop device 310 safely reaches at least the first retaining step of the multiple steps 312 located in zone 0. This first retaining step determines a distance "C" ( figure 17 and figure 20)

  <Desc / Clms Page number 43>

 optimal minimum interruption and isolation between the movable contacts 303 and fixed 302.



   In the case of medium to low short-circuit currents, the previous dimensioning of circuit breaker control energy 314, corresponding to the disconnection operation, is sufficient to carry out this operation safely and completely (free sliding of the end active 318 of the automatic blocking stop device 310 on the multiple steps 312 of the movable contact 303), the circuit breaker in question acting in this range of currents under the principle of the simple compression piston of the "puffer" type with the advantages which are inherent and described above.



   Returning to the case of high short-circuit currents and as soon as the active end 318 of the automatic blocking stop device 310 reaches the multi-step zone 312 of the movable contact 303, the stop device (s) continue to move on successive steps so that, in the event that there is a tendency for partial return for a movable contact 303 due to large subsequent pressure increases in the compression volume of the extinguishing chamber 301, the movable contact is locked exactly in the position in which it tends to trade such a return movement, preventing the latter from taking place, to a greater or lesser extent, by the action of elements 309, 310, 311 and 312, and by that the circuit breaker is able to extinguish the arc by automatic blowing by thermal expansion,

   that is to say as if it were a circuit breaker of the “self blast” type, insofar as at this moment a predetermined volume is formed between elements 303, 304, 305, 307, 315 and 316 of the extinguishing chamber, with all the advantages concerning its high breaking capacity also described above. In particular, the detail in Figure 18 shows

  <Desc / Clms Page number 44>

 this possibility, and more specifically the movable contact in the automatic locking position.



   As soon as the arc is interrupted, the pressure in the compression and thermal expansion volume 306 drops rapidly so that the energy stored in the circuit breaker control mechanism 314, when the moving contact 303 is automatically blocked, completes the complete disconnection stroke L of the latter, the circuit breaker remaining beyond in the open position, close for a subsequent closing operation.



   The stop device 310 can in turn naturally be composed of a number "n" of stop devices of different length so that, given an identical number "e" of retaining steps in the multiple steps 312 of the mobile contact 303, better e / n positioning accuracy of the mobile contact can be achieved. The number of steps in the zone 0 which corresponds to the steps 312 can vary, depending on the case from one to any number required and these can be arranged in a variable manner in said zone.



   Likewise, the entire automatic blocking mechanism 309, 310, 311 can be used once, or as often as necessary, for the same extinguishing chamber 301 in order to obtain the rigidity necessary for high powers of short -circuit.



  Positioning accuracy even greater than that above may be possible by locating (for example) the pivot shafts of the stop devices 310 at different heights.



   When the circuit breaker must be closed, FIG. 19, it is sufficient to communicate a release command to the connection member of the circuit breaker control mechanism 314 so that the latter provides the energy necessary to carry out this operation. At the end of this, the circuit breaker remains in

  <Desc / Clms Page number 45>

 closed position and is ready for further opening operation.



   It should be noted that during the closing operation, the automatic automatic locking mechanism 309, 310, 311 and 312 remains inactive, allowing the free movement of the movable contacts 303 in this operation, because there is no increase. pressure during the latter in the thermal expansion and compression volume 306 of the extinction chambers 301.



   It follows from the structure described above, first that the high voltage circuit breaker object of the invention combines the advantages of circuit breakers of the "puffer" type and of the "self blast" type, although it eliminates the problems of each of them, by allowing an extremely simple structure as regards both the control means and the arc interrupting means, by making it possible to use usual materials at low cost and low pressure in the medium of insulation and blowing.



   It is therefore also possible to greatly reduce the energy required for control purposes and, beyond, to obtain better mechanical behavior.



   The upper part of Figure 20 shows (Figure 20a) the range of possible curves for the disconnection movement under different short-circuit currents. The distance "C" determines the minimum optimum interruption and isolation distance between the fixed contacts 302 and mobile 303.



   The races marked L, M, N and 0 are respectively the following:
L, total travel of the movable contact 303,
M, travel to contact separation,
N, minimum optimal isolation and interruption stroke and

  <Desc / Clms Page number 46>

 
0, zone corresponding to the teeth or multiple steps 312 for the automatic blocking of the movable contacts 303.



   Curve I defines a minimum total travel of the movable contacts 303, in which case an automatic blocking takes place at its end in a single retaining step.



   Curve II shows a total stroke of the movable contacts 303 greater than that above, and in this case the number of retaining steps of the multiple steps 312 can vary from 2 to any number necessary.



   During the stroke N in which the contacts are separated (at the end of the stroke M), the energy communicated by the control mechanism of the circuit breaker 314 is dimensioned so as to be greater than that which is caused by the pressures produced by compression and reheating of the gas which may be present in the thermal expansion and compression volume 306 then that during this, by the dimensions of the extinguishing chamber 301 and by the appropriate operating speed of the movable contact 303, a given value cannot be exceeded so that maximum overpressure peaks cannot appear there.



   However, during the course of race M or during the partial course of race N (maximum two-thirds of N), the automatic automatic locking mechanism 309,310, 311,312 is activated pneumatically as already mentioned above, so that passing through zone 0 where the multiple steps 312 are located on the movable contact 303, in the case where there is a critical to medium short to high current for which the pressure produced, as mentioned above, in the volume thermal expansion and compression 306 may exceed the instantaneous value

  <Desc / Clms Page number 47>

 of the energy communicated by the control mechanism of the circuit breaker 314 and, beyond, inducing the induction of movement, the automatic blocking mechanism 309, 310, 311, 312 described above would begin to work.



   In the area of the curve corresponding to stroke 0 and from the step at which an automatic blocking has taken place, as soon as the arc is interrupted by automatic blowing by thermal expansion, the pressure of the volume 306 decreases rapidly, allowing that the energy remaining in the circuit breaker control mechanism 314 completely ends the total stroke L of the movable contact 303.



   The central curves of this figure 20 (figure 20b) relate to the position or stroke of the contacts and show the increases in pressure obtained in the compression volume under different short-circuit currents, showing that with maximum intensities, l The pressure increase is very high (V) and falls when the value of the short-circuit voltage decreases (W and X).



   Finally, in the lower part of figure 20 (figure 20c) the sinusoidal curves show the position of the short-circuit currents (Y) corresponding to the pressure curves above and which can be present through the circuit breaker until their interruption.



   FIG. 21 shows a graph corresponding to a characteristic curve (TTR as a function Icc) of the circuit breaker which is the subject of the present invention, curve A showing its advantages in comparison with two conventional circuit breakers which have the same energy level of their respective controls, with the operating principles of the "puffer" type on curve B and of the "self blast" type on curve C, and with the benchmarks: a, optimal zone of the "puffer" principle; b, improvement in behavior of the "self blast" type by compression

  <Desc / Clms Page number 48>

 "puffer" type prerequisite; c, optimal area of the "self blast" principle; d, critical zone: dielectric problems due to insufficient thermal contribution from the arc (insufficient arc blowing and sweeping); e, critical area:

   limits due to increased energy demand in the control = f (Icc2); f, hatched area, area of improvements using the invention in question; and g, operating zone of the automatic blocking mechanism in question for the movable contacts.



     'It should be understood that the invention is in no way limited to the embodiments described and that many modifications can be made to these without departing from the scope of the present invention.


    

Claims (20)

 CLAIMS 1. High voltage gas circuit breaker, comprising extinguishing chambers similar to the type which has a compression piston, characterized by actuation under a mixed principle of arc extinction, either by simple compression or by automatic blowing by expansion thermal and, in borderline cases of the actuation ranges of either principle, by combination of the two, the range of low to medium short-circuit currents being that in which the circuit breaker acts under the principle of simple compression piston, while in the range of medium to high short-circuit currents it acts under the principle of automatic blowing by thermal expansion, automatically blocking by means of an appropriate mechanism, during the opening operation,  the movable contacts of its extinguishing chambers, forming a fixed volume momentary until the arc is interrupted and suitable for the operation of this principle, and according to the principle in question, within the operating range under the principle of automatic blowing by thermal expansion the preliminary compression produced by the preliminary operation of the simple compression piston type allowing a significant reduction of the filling pressure of the gas in the chambers of the circuit breaker compared to the filling pressures necessary in circuit breakers working only under the principle of automatic blowing by thermal expansion.  2. High voltage gas circuit breaker, comprising extinguishing chambers similar in embodiment to those having a compression piston, which is of the type provided with a mechanical control based on a load shaft (1) which can be controlled by means of a suitable coupling and drive mechanism (14) by a geared motor  <Desc / Clms Page number 50>  tor (12/13) or by a crank (11) to band a closing spring (7), which is retained at the end of this operation by a usual mechanism of retention and release and which, after being released from this mechanism retaining via a cam (9) attached to the load shaft (1) and a transmission lever (10), acts on an output shaft (2) to which is coupled a lever (5 ) whose pivoting movement is transmitted to the transmission (16)  connecting the movable contact (17) of the circuit breaker to an opening spring (6), according to claim 1, characterized in that its extinguishing chambers act on a combined principle of extinction and arc blowing either by simple compression either by automatic blowing by heating and thermal expansion of the insulating gas used and, in borderline cases of the operating ranges of one or the other principle, by a combination of the two, this circuit breaker being produced so that the lever ( 5) coupled to the output shaft (2) is constructed so as to form an automatic locking cam on which acts a stop device (4) permanently actuated by an antagonistic spring (8), this stop device (4) being lifted from a smaller radius area (r) of the automatic locking cam (5) by the action of a pawl (3)  mounted on the load shaft in order to block the step of the automatic locking cam (5) in the closing operation, and to release the stop device (4) at the end of this operation to locate the latter in the highest zone of the self-locking cam (5) which corresponds to its largest radius (R), the stop device (4) attached to the spring (8) having been designed to act freely in the opening operation independently of the position of the pawl (3) and to automatically prevent the return movement of the automatic locking cam (5) and beyond the movable contact (17), i.e. the system  <Desc / Clms Page number 51>  acts in a predetermined area in the case where there is a tendency to reverse the movement of this contact (17) in a closing direction with the fixed contact (23)  due to the pressure produced in the extinguishing chamber (15) by heating and by the thermal expansion of the gas, in medium to high critical short-circuit currents if the above pressure reaches an amplitude exceeding that which is equivalent to the momentary stress communicated by the disconnection spring (6) when the active end (25) of the stop device (4) is engaged in the multiple steps (24) of the automatic locking cam (5), so that the circuit breaker which has operated until now under the principle of simple compression, as is the case for medium to low short-circuit currents, automatically switches to operation under the principle of automatic blowing by thermal expansion of the insulating gas used , until the arc is interrupted.  3. High voltage circuit breaker according to either of claims 1 and 2, characterized in that the automatic blocking cam (5) has multiple steps (24) on which the active end (25) of the device stop (4) acts so that, in the case where there is a tendency of a return movement for the movable contact (17), a blocking follows at the same time as such a trend appears, this automatic blocking cam (5) forming an integral part of an engagement and release mechanism (26) responsible for fixing the automatic locking cam (5) when the circuit breaker is closed and, by external and usual actuation on said mechanism to release the cam, the circuit breaker opening process starting by allowing the opening spring to perform its function, with the consequent rotation of the automatic locking cam,  and mobile contacts.  <Desc / Clms Page number 52>    4. High voltage circuit breaker according to any one of the preceding claims, characterized in that the stop device (4) may include a number "n" of stop devices of different length so that given a number Identical "e" of retaining steps in the automatic locking cam (5), one can obtain a better positioning accuracy e / n of the movable contact.  5. High voltage circuit breaker according to any one of the preceding claims, characterized in that the mechanical assembly formed by the elements (3), (4), (5) and (6) can be applied once or several times in the same circuit breaker.  6. High voltage circuit breaker according to any one of the preceding claims, characterized in that the said guide cylinder (21) can be extended in a conical extension in its zone of attachment to the chamber (15) so that a angle a can vary from 0 to 900 and the distance "D" is always equal to or greater than the extinction stroke of the piston (20) corresponding either to the first or to the last retaining step provided in the direction of disconnection, by combining the elements (4) and (5), FIG. 2a, preferably the distance "D" can also be equal to or less than the total stroke of the piston, allowing in the latter case an extremely rapid evacuation of the pressure remaining in the thermal expansion and compression chamber after the short circuit has been interrupted,  by the space formed between the two elements (20) and (21), Figure 2b.  7. High voltage circuit breaker according to any one of the preceding claims, characterized in that the guide cylinder (21) which can be made of a conductive or electrically insulating material is separated from the walls of the chamber (15) so as to protect the internal walls, and on the  <Desc / Clms Page number 53>  sectioning distance of this chamber, metallization, thermal shock, etc.  8. High voltage circuit breaker according to any one of the preceding claims, characterized in that the deflector (18) can alternatively be coupled to the movable contact (Figures 1 to 3) or be fixedly mounted in the own chamber (15 ), FIGS. 5 and 6, with the arrangement indicated in these figures, in order to obtain an ideal mixture between the fresh gas compressed beforehand and the high temperature gas originating from the heating of the interruption zone in the high current phase, to induce a sweep of the arc at zero crossing by a gas flow under optimal conditions, according to the flow arrows indicated in said figures, the volume of thermal expansion and compression of the extinguishing chambers being thus configured in a specific way.  9. High voltage circuit breaker according to any one of the preceding claims, characterized in that the total stroke of the movable contact is greater than the last step of the automatic locking cam retaining (5), Figure 4, curve I.  10. High voltage circuit breaker according to any one of claims 1 to 8, characterized in that the total stroke of the movable contact coincides with the first step of retaining the automatic locking cam (5), Figure 4, curve II.  11. High voltage circuit breaker according to any one of claims 1 to 8, characterized in that the total stroke of the movable contact coincides with the last step of the automatic locking cam retaining (5), Figure 4, curve III.  12. High voltage circuit breaker according to claim 1, characterized in that it acts under a combined principle of arc interruption either by simple compression or by automatic blowing by stove-  <Desc / Clms Page number 54>  fage and thermal expansion of the insulating gas used 1 constituted on the basis of a mechanical control mechanism with a single shaft (201) controlling the circuit breaker and an energy accumulator (202), mechanical or otherwise, capable of storing the energy necessary for the circuit breaker actuation cycles, providing more than adjuncts to the control shaft (201), in addition to a transmission system (206) and (207) connecting the latter to the movable contacts (208) of the chambers (218) are duly arranged two blocks of elements, a load block (203)  and an interlocking and release block (204), the latter being in turn added to an automatic blocking mechanism (204.3), (216) which characterizes the operation of the circuit breaker so that the actuation of this mechanism automatically prevents the return movement of the control shaft (201) during the opening operation and, beyond, the movable contacts (208) in a predetermined area, when the active end of the automatic blocking stop device (216 ) is engaged in multiple steps (204.3) of the block (204) in the case where there is a tendency of reversal of the movement of these movable contacts (208) in the opening operation, caused by the pressure produced in the compression volumes of the extinguishing chambers (218) by heating and thermal expansion of the gas,  in medium to high critical short-circuit currents, if this pressure reaches an amplitude exceeding that which is equivalent to the momentary stress communicated by the energy accumulator (202) in this operation, so that the circuit breaker which would have operated heretofore under the principle of the simple compression piston as provided for in the case of low to medium short-circuit currents, automatically begins to operate under the principle of automatic blowing until the arc is interrupted.  <Desc / Clms Page number 55>    13. High voltage circuit breaker according to either of claims 1 and 12, characterized in that the automatic blocking stop device (216) can be composed by a number "n" of stop devices of different length so that given an identical number "e" of retaining steps in the multiple steps (204.3) of the body (204), better positioning accuracy e / n of the movable contacts (208) can be obtained.  14. High voltage circuit breaker according to any one of claims 1,12 and 13, characterized in that in the arc corresponding to the angle of the perimeter of the body (204), the steps (204.3) may have one or more bleachers distributed regularly or irregularly.  15. High voltage circuit breaker according to any one of claims 1,12, 13 and 14, characterized in that the perimeter of the body (204) may, in the operating zone of the automatic blocking device (s) 216), be provided with steps or multiple teeth which completely surround it, that is to say comprising the rotations corresponding to both the closing and opening operations, the number, the size and the distribution around the entire perimeter teeth or steps being variable depending on the characteristics to be obtained, when appropriate, for the circuit breaker and its extinguishing chambers.  16. High voltage circuit breaker according to any one of claims 1, and 12 to 15, characterized in that the load block (203) and the interlocking and release block (204) of the circuit breaker are mounted coaxially on the control shaft (201) of the circuit breaker, a one-way axial coupling (205) being established between said load (203) and interlocking (204) blocks, another coupling system  <Desc / Clms Page number 56>  radial in one direction having been provided and in the form of a free wheel (210) adjoining a ring gear (211), these last two elements being designed to charge the accumulator with energy by any appropriate means, in particular the block aforementioned engagement (204) having one side with steps or multiple toothing (204.3) on which one or more automatic locking stop devices (216)  can act laterally.  17. High voltage circuit breaker according to any one of claims 1, and 12 to 16, characterized in that the automatic blocking mechanism, which comprises multiple steps (204.3) and the automatic blocking stop devices (216 ) can be located anywhere in the movement transmission system of the circuit breaker control shaft (201) with the moving contacts (208) of the extinguishing chambers (218), including on the moving contacts (208) , with the corresponding link (224) for its control from the control shaft (201), which can be arranged inside or outside the extinguishing chambers (218) according to the arrangement of said elements and in depending on their position, or even be a combination of the two arrangements.  18. High voltage circuit breaker according to claim 1, characterized in that its extinguishing chambers (301) act under a combined principle of automatic blowing and arc interruption, either by simple compression or by automatic blowing by heating and by thermal expansion of the insulating gas used and, in borderline cases of the operating ranges of one or the other principle, by a combination of the two, for this purpose the chambers (301) preferably being formed on the basis of a fixed contact (302) with its corresponding external connection terminal, a movable contact (303) electrically connected by means of sliding elements to a base plate (316) of which  <Desc / Clms Page number 57>  a second connection terminal protrudes, a membrane (307), a guide cylinder (315) and a transmission bar (313)  connecting the movable contact (303) of the extinguishing chambers (301) by means of mechanisms suitable for the circuit breaker control mechanism (314), in which the elements (303,307, 315 and 316) define a volume of compression and expansion thermal (306) of the insulating gas used, all being mounted in an insulating container gas-tight and at a given filling pressure of the insulating gas, as is customary, and further equipped, as a basis for the present invention, with or several sets comprising the following elements:  a pneumatic control piston (309) connected directly to the volume (306) via the hole (308), one or more automatic blocking stop devices (310) mounted on a pivot shaft, one or more counter springs (311), all being located on the base plate (316), and multiple steps or teeth (312) with one step or any number of steps if necessary, on the guide tube of the movable contact (303) , these elements generally forming an automatic blocking mechanism acting, when appropriate, in the operation of opening the extinguishing chambers (301) as soon as the compression volume (306) has reached a given overpressure activating the mechanism, by causing the stop device (310) to pivot until its active end (318) rests on the movable contact (303)  in a stroke less than N, after which it is ready to be controlled, which automatically prevents the return movement of the movable contact (303) during the opening operation, in a given zone when the active end (318) of the automatic blocking stop device (310) is engaged in the multiple steps (312) of the movable contact (303), in the case of a tension  <Desc / Clms Page number 58>  dance of inversion of the movement of the movable contacts (303) in this operation due to the pressure produced in the thermal expansion and compression volumes (306) of the extinguishing chambers (301), by heating and by thermal expansion of the gas,  in medium to high critical short-circuit currents if this pressure reaches an amplitude exceeding that equivalent to the momentary force communicated by the circuit breaker control mechanism (314) in this operation, so that the circuit breaker which would have operated so far under the principle of a simple compression piston, as provided for in the range of low and medium short-circuit currents, automatically begins to operate under the principle of automatic blowing by thermal expansion of the insulating gas used, up to l 'arc interruption.  19. High-voltage circuit breaker according to either of claims 1 and 18, characterized in that the total strokes of the movable contacts can coincide with a first and only step, curve I, FIG. 20, or, in the case of multiple steps, curve II, FIG. 20, with the last of the consecutive steps of the steps (312) of the movable contact (303).  20. High voltage circuit breaker according to any one of claims 1,18 and 19, characterized in that in the case of the use of several steps in these steps (312) of the movable contact (303) these can be distributed regularly or irregularly over the length between the first and the last.