US3247338A - Actuating system for simultaneously engaging or disengaging the contacts of multiple circuit breakers - Google Patents

Description

3,247,338 TEM FOR SIMULTANEoUsLY ENGAGING 0R DISENGAGING THE CONTACTS oF April 19, 1966 .1. 1 GRATZMULLER ACTUATING SYS MULTIPLE CIRCUIT BREAKERS Filed May 20, 1963 4 Sheets-Sheet 1 FIG l Aprxl 19, 1966 J. L. GRATZMULLER 3,247,338

ACTUATING SYSTEM FOR SIMULTANEOUSLY ENGAGING OR DISENGAGING THE CONTACTS OF MULTIPLE CIRCUIT BREAKERS 4 Sheets-Sheet 2 Filed May 20, 1963 April 19, 1966 J. L. GRATzMuLLER 3,247,338

FOR SIMULTANEOUSLY ENGAGING OR DISENGAGING THE CONTACTS OF ACTUATING SYSTEM MULTIPLE CIRCUIT BREAKERS 4 Sheets-Sheet 3 Filed May 20, 1963 FIG.3

FIG.4

April 19, 1965 J. l.. GRATZMULLER 3,247,338

FOR SIMULTANEOUSLY ENGAGING ACTUATING SYSTEM OR DISENGAGING THE CONTACTS OF MULTIPLE CIRCUIT BREAKERS 4 Sheets-Sheet 4.

Filed May 20, 1963 United States Patent O 3,247,33S ACTUATNG SYSTEM FOR SEMULTANEGUSLY ENGAGENG R BENGAGNG THE 09N- 'IAC'IS 0F MULTEPLE CIRCUIT BREAKERS .lean Louis Gratzrnulier, 66 Blvd. Maurice Barres, Neuiliy sur Seine, Seine, France Filed May 29, 1963, Ser. No. ZSLWS Claims priority, application France, May 25, 31962, 398,712; ct. 12, 1962, 912,043 8 Claims. (Cl. 26d-48) The present invention relates -to circuit-breakers provided with multiple circuit-breaking chambers.

It is known that, with constantly increasing volta-ges in grids, the practice has been introduced of mounting the circuit-breaker chambers of circuit-.breakers in series, especially for the purpose of preventing a prohibitive increase in the height of circuit-breaking dash-pots and in -tlhe'cxtent of displacement of moving contacts.

`lt is manifest that, in order to ensure that s-uch a system is reliable and safe, opening and closing of contacts m-ust be effected simultaneously on all chambers to prevent one of the chambers from being subjected to the total voltage. An object of the present invention is to ensure such simultaneous action not only in normal operating conditions, but also in cases of damage occurring to equipment so that there is a complete guarantee of safe Working in all circumstances.

Moreover, if the interruption of currents at very high tension may be resolved by -the system of distribution mentioned above, it nevertheless remains imperative that the circuit-breaking chambers be mounted at a very great height with a View to insulation from the ground. This involves certain d-iiculties, for example in regard to the construction of insulating pillars and to the control of -moving contacts situated at some considerable distance from the control point located at the earth potential.

Various types of equipment have been proposed in which the ditiiculties are overcome, and in particular those described in French Patents No. 1,278,010 entitled insulating Support and No. 1,293,609 and entitled Circuit-Breaker With Automatic Integrated Release Means in the name of the same inventor.

The present invention relates in particular to circuitbreakers of the 4type described in the second of the above patents, that is to say to the case Where the equipment is provided with a plurality of circuit-breaking chambers. It is sumcient to recall that, when employed for high tension working, these circuit-breakers are provided With a `connecting insulator rod inserted between a drive member (hydraulic cylinder) lat earth potential and the moving gear under tension. The hydraulic cylinder is for the purpose of closing the circuit-breaker and maintaining it closed against resilient means which are always available and are capable of producing disengagement or opening of the circuit-breaker, with the resilient means being located in the portion under tension. Consequently, the connecting rod or rods always operate under tractive stress.

For high tensions the circuit-breaking chambers of several circuit-breakers of this type may be coupled in electrical series, While all cylinders may be supplied or exhausted simultaneously (for example, by means of hydraulic connections in parallel) in order to produce substantial synchronization of the displacements of all moving contacts in the course of engagement or disengagement. One must however envisage the possibility of ice breakage of one of the connecting insulator rods or of any one of the connecting members, and such a breakage would occasion the separate disengagement of one or more chambers controlled by this rod. The chamber or chambers would thus be subjected to the total voltage, while the remaining chambers would remain in the closed or engaged position.

The object of the present invention is to obviate this disadvantage, whereby, in the case of damage occurring to one of the connecting systems, all circuit-breaking chambers would Ibe simultaneously disengaged.

According to the invention, in a circuit-breaker of multiple chamber type comprising several hydraulic cylinders each acting upon one connecting insulator rod, each of said hydraulic cylinders is designed so that its piston is capable of moving beyond its dead-center position. That is to say beyondy the position in which the moving Contact or contacts which it actuates by way of an insulator rod, are engaged or closed, with each hydraulic cylinder comprising in addition means for producing automatically the simultaneous evacuation of all cylinders if their pistons proceed .beyond the normal dead center position mentioned above.

By virtue of this arrangement, if one of the connecting insulator rods happens to break, the moving contact or contacts associated with such rod proceed to the disengaged or open position under pressure of resilient means located in the part under tension, but, simultaneously, the piston of the corresponding cylinder is urged by the oil-pressure beyond the dead-center position, thus actuating the device for general evacuation of the cylinders, where-by all other circuit-breaking chambers are brought. to the disengaged position.

Since the inertia of the cylinder piston is less than that of the moving gear of the chambers, the signal for evacuation of the cylinders .may be produced before the eiiective disengagement of the dam-aged chamber or chambers, where-by the disengagement of all chambers may be rendered substantially simultaneous. Furthermore, shock-absorbing devices (oil dash-pot) are provided in the part under tension, as in the case of the second of the patents mentioned above, and assist in delaying disengagement in the case of a sudden fracture of a connecting rod.

n the case where one of the connecting rods might be stretched :beyond a pre-determined danger limit without fracture, the piston likewise proceeds beyond its normal dead-center and produces the same general evacuation of cylinders including the cylinder in question, that is to say, simultaneous disengagement of all chambers.

in a circuit-breaker according to the invention various means may be employed which respond to the position of the pist-on of a hydraulic cylinder and are designed to produce simuitaneous evacuation or" all cylinders. This evacuation of tluid may be controlled, such as for exam- Iple electrically by contact-makers actuated by the piston, or else mechanically by valves opened by the piston or by -a member integral with the piston when it exceeds the normal dead-center position.

According to a particularly simple embodiment, all hydraulic cylinders are interconnected in hydraulic communication by one or more lines of large cross-section, with exhaust ports being provided in each hydraulic cylinder which are in communication with a zone of low pressure and are uncovered by the piston when it passes beyond normal dead-center. With this arrangement,

when an exhaust port is exposed (by fracture or stretching of the insulator rod connected to this piston), the oil contained in the hydraulic circuit formed by the cylinders and their communicating lines is rapidly exhausted, which produces instant disengagement of all circuitbreaking chambers.

In accordance with a further embodiment, it is proposed to dispense with the -above exhaust ports and employ hydraulic cylinders without a base at the low pressure side (or, preferably with a removable base), whereby the piston may be pushed from its cylinder when'breakage of the insulator rod occurs, and evacuation can proceed freely over the entire cross-section of the cylinder.

The cross-section of the lines is so calculated that the rate of exhaustion exceeds the rate of supply at the moment of pressure-oil from the power source (for example, an oil-and-air accumulator) to the cylinders.

In a circuit-breaker according to the invention, each hydraulic cylinder may control one or more than one chamber by way of an insulator rod. The provision of a plurality of chambers is common for very high tensions where one may be required to arrange possibly 6 to l0 circuit-breaking chambers in series. In this case, it is advantageous to group the chambers in pairs over 3 to 5 identical insulator pillars, each being provided with a control cylinder and insulator rod.

The mechanical connection between a control rod working under traction in accordance with the invention and a plural-ity of moving contacts may be so devised that, for a given displacement of the rod, the displacements of Y the moving contacts are identical, or else the stress irnposed on the moving contacts is identical. In both cases,

.in order to reduce inertia, it is preferable that themembers in order to be displaced over very large distances should be as light as possible. For this reason, it is Vof advantage to provide the resilient release means, together with the shock-absorbing and speed-control means, on the members whose motion i-s accompanied (or substantially accompanied) by the insulator rod, and not on the moving contacts. In other words, these means are preferably located towards the insulator rod in relation to the mechanisms for the transmission of the drive with reverse-motion andv reduction which are placed between the source of traction and the moving contacts.

Thus, in the preferred embodiments of the invention, where one and the same insulator rod controls a plurality of circuit-breaking dash-pots, each of the moving contacts possesses its own transmission mechanism with reverse-motion, whereas the resilient release means, together with the shock-absorbing means may be allotted to each chamber, or, on the other hand, be common to all chambers.

In order to facilitate comprehension the invention will now be described in detail with reference to the accompanying drawings which illustrate certain embodiments of the invention by way of examples of a non-limitative character.

In the drawings:

FIG. 1 is a diagrammatic view of a circuit-breaker in accordance with the invention, comprising two circuitbreaking chambers, each mounted on an insulator pillar;

FIG. 2 is a view, partly in section, of a further ernbodiment in which each insulator pillar supports two circuit-breaking chambers controlled by one and the same insulator rod;

FIG. 3 is a fragmentary view partly in section and partly in cross section of a modied form in which each insulator pillar likewise supports two circuit-breaking chambers;

FIG. 4 is a view taken along the line IV--lV of FIG. 3;

FIG. 5 is a fragmentary view partly in section andV I partly in elevation of a circuit-breaker with two circuitil breaking chambers, in which motion is transmitted from the insulator rod to the moving contacts by means of a mechanism of cranks and levers.

The circuit-breaker shown diagrammatically in FIG. l is provided with two circuit-breaking chambers in series and comprises two identical units composed of a moving Contact 1 held permanently in the oit-position by a spring 2 located in the part under tension and brought into contact by a hydraulic cylinder 3 situated at the earth potential at the base of an insulator pillar 4 lled with o-il. rthe connection between the cylinder and the moving contact is provided by a transmission and reversing mechanism 6 in the form of a rack-and-pinion arrangement for example.

The line in which the current is to be cut or restored is represented by lead-in and lead-out conductors 7, 7' and a linking conductor 3.

in the embodiment illustrated, the cylinders 3, 3 are interconnectedin parallel hydraulically by a line 9 to which is connected a line lll from a source of luid under pressure (not illustrated; for example a hydraulic power unit comprising an oil-and-air accumulator). The line llt) provides the pressure-oil to feed the hydraulic cylinders which cause the two moving contacts ll, 1' to engage simultaneously and subsequently maintain these contacts in the on-position by hydraulic pressure and without any mechanical locking means.

The length of the `cylinders 3, 3' is so calculatedV that pistons li, l1 at their normal bottom-dead-center position, do not meet bases l2, l2 which are simple removable covers.

n 4the position illustrated in FIG. l, the circuitbreaker is in the closed position, that is to say the oil pressure is maintained in the circuit comprising the lines 9, lll and hydraulic cylinders 3, 3', the pistons are at bottom-dead-center, and the moving contacts l, l' are engaged in fixed upper contacts 13, 13. Connecting insulator rods 5, 5 are thus under tractive stress between their respective cylinders and release springs. lf any one connecting element lying between a moving Contact and its cylinder happens to break, for example the insulator rod 5, the moving contact i is urged towards the olfposition by pressure of its spring 2, while at the same time the piston 11, now no longer retained by the rod 5, is urged downwards towards the `base of the cylinder yby the oil pressure. The cover i2 is pushed open, which produces immediate exhausting of the cylinder 3 towards the line 9 and cylinder 3 whose cover has been removed. The moving contact l is thus also released under the pressure of its spring 2.

The line 10, which remains at all times connected to the pressure-huid source, is provided with a calibrated jet it', so that the rate of exhaustion of the line 9 is greater than the rate or" feed from the line itt.

The two moving contacts l, 1 are released simultaneously which prevents one of the circuit-breaking chambers being subjected, even temporarily, to the total voltage which it is not designed to support.

indeed, as soon as the piston il begins itscomplementary downward displacement when the insulator rod 5 break-s, the piston 1l' moves in exactly the opposite direction under the pressure of the return spring, and the `oil of the cylinder 3' begins to pass to the cylinder 3. The two contacts l, l. are thus released simultaneously.

Moreover, the moving mechanism of Ithe circuit-breaker possesses greater inertia than the piston 3 and is provided, in the part under tension, with shock-absorbing and speed control means whereby the exhaust signal occasinned by the complete displacement of the piston 1l is transmitted before the moving Contact l has been able to leave the fixed upper contact 13. Consequently, the effective circuit break occurs in all chambers simultaneously. It is also possible to provide in the vicinity of the cylinders 3, 3 quick-acting exhaust valves ld, 14' of a known type for providing direct evacuation of the with racks and pinions 19, i9 and 2i), 2d.

. mission and reversing mechanism.

oil to a reservoir without passing through the line 9 (which may Ibe of some considerable length), due to the pressure-drop produced by the sudden thrust ot the piston 11.

Such quick-acting exhaust valves have been described, especially in French Patent No. 1,099,949 and in Certificate of Addition No. 73,084, both tiled by the same inventor under the .title Quick-Acting Exhaust Device for Hydraulic Cylinders.

It is manifest that the invention may also be applied to a circuit-breaker comprising any number ot insulator pillors and cylinders, with each of said pillars supporting one or more circuit-breaking chambers,

In the embodiment illustrated in FIG. 1, evacuation `may be effected `by exhaust ports provided in the cylinders. Those ports are uncovered by the pistons when the latter pass -beyond their dead-center position, or else suiiicient travel of the pistons within the cylinders is provided so that all undamaged cylinders are drained into the cylinder whose connecting mechanism is tractured.

The provision ot a line 9 of large cross-section for providing communication between the various cylinders as illustrated in FlG. l, offers a particularly simple arrangement, since this line also serves for supplying all cylinders in parallel for closing the circuit and maintaining such circuit closed. It would be advantageous however it it were possible to provide calibrated jets on the supply means y)tor each of the cylinders in order to determine the speed of engagement for circuit-closing, 'but these jets `would impede safety exhaustion in the case of a broken connecting rod. Consequently, in this embodiment, control ot` the speed of circuit-closing is eiected by systems of hydraulic shock-absorbing elements provided in the part of the circuit-breaker under tension, and not by feed jets.

In accordance with further embodiments, safety exhaustion may be controlled (for example through valves or electro-valves) by an element integral with the piston instead of by the piston per se, whereby the exhaust lines may be independent of each other, with the speed of the circuit-closing being controlled -by means of jets disposed over the supply circuit for the cylinders.

In the case where each of the insulator pillars carries several circuit-breaking chambers, the embodiment illustrated in FIG. 2 may be employed and in which one and the same insulator rod 5 actuates a plurality of moving contacts 15, i5.

A connecting mechanism with a rocking lever In and cranks i7, I7 links the extremity of the insulator rod 5 to racks I3, IS engaging the transmission mechanisms In this case, the power for circuit-closing is distributed equally between the ltwo circuit-breaking chambers. Each of the chambers may have its own individual release elements namely `springs 2i, 2 and shock-absorbing means Z2, 2.2 accommodated in an oil-filled chamber 23 located beneath the chambers.

lt will be seen that, with the chambers moderately inclined to the vertical, it is possible to obtain considerable spacing between the tops of said cham-bers which are at different potentials.

A further embodiment of a connecting mechanism between an insulator rod 5 and two circuit-breaking chambers mounted on one single insulator pillar 4 is shown diagramrnatically in FIGS. 3 and 4. In this arrangement, resilient release means spring 2d and shock-absorbing and speed control means oil dash-pot 2S are common to the two chambers that is to say, they iniiuence the actual connecting insulator rod between its upper part and the transri`his mechanism comprises a double-sided rack 26 which meshes with two identical pinions 27, 27 whose shafts 28, 28 each carry a toothed wheel 29, 29 respectively. These two wheels engage racks 3d, 30' secured to the moving contacts I5,

15 respectively. It will be seen that, with this type of mechanism, transmission of motion with reversing of direction between the insulator rod and the moving contacts occurs, not with equality of stress, but with equality of travel or the moving contacts since these latter components are connected by a positive drive to the insulator rod.

The toothed wheels 29, Z9' are arranged symmetrically about the axis of the rack 26 (FIG. 4) so that the racks 30, Bti lie in two ditlerent vertical planes. This arrangement oiiers the advantage that in addition to symmetry, it enables the mechanism housing (not illustrated) to be divided into three compartments, each sealed from the other, with tight joints 31, 3l being provided at the bearings of the shafts 23, '23. Means of :this type for separating the oil capacities of the circuit-breaking chambers from the transmission mechanism have been described in the first Certificate of Addition to French Patent No. 1,293,609 led on March 21, 1962, under the No. 891,729'.

FIG. 5 is a view o'r` a modied form of construction combining the equal stress transmission system shown in FlG. 2 and the equal travel system shown in FIG. 3.

In the case of this modification, the rocking lever 16 is replaced by intermediate piece 32 of triangular construction which is pivotally connected by one of its apices to the control rod 5', with its other two apices being connected to the small cranks 17, I7 identical to those employed in FIG. 2. With this transmission mechanism, motion is normally transmitted by giving equai travel to the two moving contacts, but the intermediate piece 32 is capable however of rocking slightly during displacement.

In :the case of the embodiment illustrated in FIG. 6, the transmission mechanism employed between the extremity of the connecting insulator rod (or piece integral with and moving with said extremity) and the moving contacts, is in 4the form of a crank and lever mechanism producing amplification of movements and reverse-motion. This mechanism is accommodated in an oil-lled casing which also encloses the shock-absorbing system and is mounted on the upper portion of the insulator pillar supporting the circuit-breaker and carries the circuitbreaking chambers. It is also possible to employ a dry casing and in which case the hydraulic shock-absorber is provided with its own oil supply.

At the foot of an insulator pillar 192 there is mounted at the portion at earth potential, a hydraulic cylinder (not illustrated) which exerts a pull on a hollow connecting insulator rod Ille, preferably of plastic reinforced with fiber-glass. The upper extremity of the rod lit-i is connected by means of a Steeve 196 to a shock-absorber rod 168 carrying a piston 1li@ slidably mounted within a shock-absorber cylinder 112. This cylinder is connccted to top cover 114 of the insulator pillar N2 and is immersed in the oil contained in a casing lie also mounted on the upper part of the pillar 162. Packing material IIS ensures duid-tightness during motion of the rod 163 between the casing 116 and the interior of the pillar 1&2 which is filled with insulating oil.

Two circuit-breaking chambers 120, 126' arranged in a general incline, are mounted on the casing 1Std.

Since these chambers are identical and symmetrical about the vertical axis of the circuit-breaker, only the one illustrated on the ieft of the figure wiil be described together with its associated mechanism.

Within each circuit-breaking chamber a moving contact 22 rmay be provided, which is slidable within a lead-in contact 124 and may engage at top-dead-center in a iixed contact (not illustrated) but is located at the upper part of the chamber (in the ligure the circuitbreaker is shown in `the reiease or off position).

The transmission mechanism between the working insulator rod IM and each of the moving contacts comprises a lever 12e provided with arms of unequal length and which is pivotally mounted on a ixed axis 128 carried aaaasss by the casing 116 and comprises two small connecting cranks 130 and 132. The crank 130 is pivotally connected by one of its extremities to extremity 1310i the longer arm of the lever 126, and by its other extremity to a sliding cross-piece 13- to which the moving contact 122 is secured and whose movement is guided by two guide rods 136, 136 which may also assist in maintaining the circuitbreaking chamber 120 in position. The crank 132 is articulated by one extremity to extremity 1330i? the shorter arm of the lever 126, and by its other extremity to a connecting piece 140 which is secured, for example by means of a pin M2, to the rod 108 or the shockabsorber and is movable therewith. The connecting piece 140 serves as a stop for the completion of the release stroke and also as a connection tothe spring release means which will be described hereinafter. The ratio of the arms of the lever 126 is so calculated that, for a short displacement of the group comprising the cylinder piston, insulator rod 104, shock-absorber rod 108 and conncctf ing piece 140 (that is to say, for a small consumption of oil in the cylinder), the moving contacts perform their complete stroke. By Way of example, a transmission mechanism is illustrated which offers a multiplication ratio of approximately 1A with reverse-motion.

In a circuit-breaker according to the invention, the release spring is located in the part liable to be under tension, as has been described in French Patent No. 1,293,609 and also in the first Certiicate of Addition No. 891,729.

In the case of embodiment illustrated, the release spring 143 is located above the casing 116 and between the circuit-breaking chambers 120, 120. It is securely ixed at its lower extremity to a ibase 144 mounted on the casing and cooperates at its upper extremity with a movable thrust washer 1de secured to a rod 14S integral with the connecting piece 140.

The manner of working of the circuit-breaker, which lis suiiioiently clear from the above description, it may suice to say that, departing from the release position shown in PIG. 6 when pressure-oil is admitted to the control cylinder, the insulator rod 104 together with all 40 the moving elements connected thereto, is pulled downwards and is subjected to a tractive force on encountering the pressure of the release spring 143. The downward movement of the connecting piece 140 causes the two levers 126 to pivot and assume the position 126 shown diagramrnatically by the dotted lines on the lett of the figure and corresponding to the insertion of the moving contacts 122 into their respective fixed contacts. This dead-center of the engage or close stroke may be lixed Iby theV striking of a sleeve 150 keyed to the rod 148 against the upper part of the base 144.

Engagement of the contacts may be automatically maintained by the oil-pressure which remains at the level in the cylinder, the release or disengaging action being obtained by exhausting the cylinder. When this occurs, the release spring 143 brings the thrust washer 146 once more upwards, thus involving the whole group 148-140- 108, whereby the moving contacts are withdrawn by the pivoting of the levers 126.

In the transmission mechanisms shown in FlG. 6, the two symmetrical cranks 132 may be connected alternatively by a common pivot to the connecting piece 140 instead of to two separate pivots 152, 154. Likewise, the release spring and shock-absorber may be located at different points from those illustrated, and it is possible in particular to mount the shock-absorber within the spring, with said unit being located inside or outside the casing 116.

If each of the circuit-breaking chambers is designed for example for 75,000 volts, a 450,000 volt circuitbreaker may be employed in accordancewith the invenrod in accordance with one of the embodiments of F lGS.

2, 3, 5 or 6. Various other combinations of chambers and pillars may be realized, with the saine degree of safety being ensured even in the case of breakage of a connecting eiement.

It is known that the response of circuit-breakers is not only dihoult on a short-circuit, but also in the case of an insulating fault occurring on the supply line not far from the circuit-breaker (a case referred to generally as a kilometric fault) and also in the case of the circuitbreaking of no-load lines where the capacity of conductors plays an important part. It would appear then that, as the case may be, the circuit-breaker may -be presented with phenomena which are purely of ohmic, or self-inductances, or even capacitive type, and that it must be capable of ensuring the break even in the case of very considerable dephasing in one or other direction of voltage in relation to intensity.

Reliability of the circuit-break and of the maintenance of insulation after the break in diiiicult cases where the above-mentioned self-inductance or capacitive phenomena occur, might be considerably improved by increasing the extent of travel of the moving contactsfwhile retaining their high speed. lt is known however that such an increase in displacement is diilicult to obtain in circuitbreakers with conventional actuating means. in order to facilitate circuit-breaks `on a short-circuit, it has also been suggested that a resistance be provided on each circuit-breaking chamber which resistance is arranged in parallel with the upper and lower xed contacts (the resistance rnust be cut in turn after opening of the circuit-breaker) or preferably, the insertion of a resistance betweenV the upper contact and an additional, intermediate rixed contact.

The break is thus effected in two stages, with the rst stage consisting of inserting said resistance in the circuit, and the second stage of interrupting the current passing through the resistance. In this case, however, such a solution requires a quite considerable .increase in the total displacement of the moving contact.

In the case of circuit-breakers provided with multiple chambersin series, such as those according to the present invention, each chamber is of course subjected to the phenomena which has just been described, but, in addition, the distribution of tension amongst the vario-us chambers after the break may tend to be irregular, especially if no auxiliary distributor equipment (resistances or condensers) is provided. lt is therefore also advantageous in this case to provide additional displacement after circuit-breaking on the moving contacts.k

Now, the increase of displacement of the moving contacts may be effected without difliculty on circuit-breakers according to the invention by virtue of the pull-system with reduction and reverse-motion, especially with the use of racks and pinions. Indeed, it is suiioient to increase the travel of the drive member, that is to say, of the hydraulic cylinder associated with the connecting insulator rod controlling the moving contact or contacts, and Yto extend by several teeth the racks connected to the insulator rod and moving contacts. Such an arrangement enables the path of the moving contacts to be extended without any great increase in the inertia of the parts or of the volume of the casings and is described in the French Certificate of Addition No. 891,729.

lt is manifest that the invention is by no means limited to the examples described and illustrated but that various modications, apparent to the technician, are possible, following the applications envisaged and without thereby departing from the spirit of the invention.

What l claim is: f

1. An actuating system for an electric circuit breaker of the type including at least two stationary contact members, at least two contact members movable each relative to one of the stationary contact members between closed and opened positions, and elastic means arranged to urge constantly each movable contact member towards the opened position, said actuating system including a plurality of single acting Huid pressure actuators, there being one actuator for each two movable contact members, each actuator including a cylinder, a piston slidable in the cylinder through a limited stroke extending between a lirst position of the piston corresponding to the closed position of the correlated movable contact members and a second position of the piston corresponding to the opened position of the correlated movable contact members, means including a supply line interconnecting the interior of the cylinders behind the pistons for supplying pressure uid to the interior of all of the cylinders, transmission means operably relating each movable contact member with the corresponding piston for moving the movable contact members to the closed position against the action of the elastic means as the pistons are moved to the first position under the application of pressure fluid and for moving the pistons upon pressure tiuid release to the second position under the action of the elastic means, said transmission means including a tubular pillar of insulating material supported by the cylinder of each fluid pressure actuator, an insulator rod extending through the pillarand connected to the piston of the associated cylinder and rocking lever means between the insulator rod and the movable contact members for equalizing the stress communicated to the movable contact members by the insulator rod, and means controlled by each piston for releasing automatically the pressure tiuid in the interior of the cylinders when one of the pistons moves past the first position away from the second position.

2. An actuating system for an electric circuit breaker of the type including at least two stationary contact members, at least two contact members movable each relative to one of the stationary contact members between closed and opened positions, and elastic means arranged to urge constantly each movable contact member towards the opened position, said actuating system including a plurality of single act-ing fluid pressure actuators, there being one actuator for each two movable contact members, each actuator including a cylinder, a piston slidable in the cylinder through a limited stroke extending between a first position of the piston corresponding to the closed position of the correlated movable contact members and a second position of the piston corresponding to the opened position of the correlated movable Contact members, means including a supply line interconnecting the interior of the cylinders behind the pistons for supplying pressure fluid to the interior of all of the cylinders, transmission means operably relating each movable contact member with the corresponding piston for moving the movable contact members to the closed position against the action of the elastic means as the pistons are moved to the first position under the application of pressure iiuid and for moving the pistons upon pressure uid release to the second position under the action of the elastic means, said transmission means including a tubular pillar of insulating material supported by the cylinder of each fluid pressure actuator, an insulator rod extending through the pillar and connected to the piston in the associated cylinder, crank means operably coupled to the movable contact members and a triangular plate connected to the insulator rod and the crank means, and means controlled by each piston for releasing automatically the pressure fluid in the interior of the cylinders when ont of the pistons moves past the first position away from the second position.

3. An actuating system for an electric circuit breaker of the type including at least two stationary contact mem. bers, at least two contact members movable each relative to one of the stationary contact members between closed and opened positions, and elastic means arranged to urge constantly each movable contact member towards the opened position, said actuating system including a plurality of single acting uid pressure actuators, there being one actuator for each two movable contact members, each actuator including a cylinder, a piston slidable in the cylinder through a limited stroke extending between a first position of the piston corresponding to the closed position of the correlated movable contact members and a second position of the piston corresponding to the opened position of the correlated movable contact members, means including a supply line interconnecting the interior of the cylinders behind the pistons for supplying pressure iiuid to the interior of all of the cylinders, transmission means operably relating each movable contact member with the corresponding piston for moving the movable contact members to the closed position against the action of the elastic means as the pistons are moved to the first position under the application of pressure uid and for moving the pistons upon pressure uid release to the second position under the action of the elastic means, said transmission means including a tubular pillar of insulating material supported by the cylinder of each iiuid pressure actuator, an insulator rod extending through the pillar and connected to the piston in the associated cylinder, a lever having opposite ends pivotable about a fixed axis perpendicular to the axes of the insulator rod and the movable contact members, means movable with said insulator rod, crank means connected to one end of the lever and to said movable means, means integral with said movable contact members and second crank means connected to the other end of said lever and said means integral with said movable contact members, and means controlled by each piston for releasing automatically the pressure fluid in the interior of the cylinders when one of the pistons moves past the first position away from the second position.

4. The actuating system as claimed in claim 3 including compression spring means located above the crank means connected to the means movable with the insulator rod.

5. An actuating system for an electric circuit breaker of the type including at least two stationary contact members, a corresponding number of contact members movable each relative to one of said stationary contact members between closed and opened positions, and elastic means arranged to urge constantly each movable contact member towards the opened position, said actuating system comprising a plurality of single acting iiuid pressure actuators, there being one actuator for each movable contact member, each actuator including a cylinder, a piston slidable in the cylinder through a limited stroke extending between a iirst position of the piston corresponding to the closed position of the correlated movable contact member and a second position of the piston corresponding to the opened position of the correlated movable contact member, means including a supply line interconnecting the interior of the cylinders behind the pistons for supplying pressure uid to the interior of all of the cylinders, transmission means operably relating each movable contact member with the corresponding piston for moving the movable contact members to the closed position against the action of the elastic means as the pistons are moved to the lirst position under the application of pressure iuid and for moving the pistons upon pressure iiuid release to the second position under the action of the elastic means, and means controlled by each piston for releasing automatically the pressure uid in the interior of the cylinders when one of the pistons moves past the iirst position away from the second position.

6. The actuating system as claimed in claim 5 in which said transmission means comprise a tubular pillar supported by the cylinder of each fluid pressure actuator and having a top end, a member of insulating material extending through each tubular pillar, said elastic means being defined by compression springs resting on the top end of the pillars, a spring compressing washer, and each member of insulating material interconnecting the corresponding piston and spring compressing washer whereby said member -is subjected solely to tensile stress.

7. The actuating system as claimed in claim 5 in which each cylinder is provided with exhaust port means so located as tobe exposed by its piston during displacement of the piston for producing evacuation of the cylinders .in response to complementary displacement of one of the pistons. y

'8. The actuating system as claimed in claim S in which each cylinder is open at the end in front of the piston f and a removable cover closes the open end so that when the piston in the cylinder moves past the rst position away from the second position, the cover is ejected thereby causing instant evacuation of all cylinders.

No references cited.

Claims (1)

1. AN ACTUATING SYSTEM FOR AN ELECTRIC CIRCUIT BREAKER OF THE TYPE INCLUDING AT LEAST TWO STATIONARY CONTACT MEMBERS, AT LEAST TWO CONTACT MEMBERS MOVABLE EACH RELATIVE TO ONE OF THE STATIONARY CONTACT MEMBERS BETWEEN CLOSED AND OPENED POSITIONS, AND ELASTIC MEANS ARRANGED TO URGE CONSTANTLY EACH MOVABLE CONTACT MEMBER TOWARDS THE OPENED POSITION, SAID ACTUATING SYSTEM INCLUDING A PLURALITY OF SINGLE ACTING FLUID PRESSURE ACTUATORS, THERE BEING ONE ACTUATOR FOR EACH TWO MOVABLE CONTACT MEMBERS, EACH ACTUATOR INCLUDING A CYLINDER, A PISTON SLIDABLE IN THE CYLINDER THROUGH A LIMITED STROKE EXTENDING BETWEEN A FIRST POSITION OF THE PISTON CORRESPONDING TO THE CLOSED POSITION OF THE CORRELATED MOVABLE CONTACT MEMBERS AND A SECOND POSITION OF THE PISTON CORRESPONDING TO THE OPENED POSITION OF THE CORRELATED MOVABLE CONTACT MEMBERS, MEANS INCLUDING A SUPPLY LINE INTERCONNECTING THE INTERIOR OF THE CYLINDERS BEHIND THE PISTONS FOR SUPPLYING PRESSURE FLUID TO THE INTERIOR OF ALL OF THE CYLINDERS, TRANSMISSION MEANS OPERABLY RELATING EACH MOVABLE CONTACT MEMBER WITH THE CORRESPONDING PISTON FOR MOVING THE MOVABLE CONTACT MEMBERS TO THE CLOSED POSITION AGAINST THE ACTION OF THE ELASTIC MEANS AS THE PISTONS ARE MOVED TO THE FIRST POSITION UNDER THE APPLICATION OF PRESSURE FLUID AND FOR MOVING THE PISTONS UPON PRESSURE FLUID RELEASE TO THE SECOND POSITION UNDER THE ACTION OF THE ELASTIC MEANS, SAID TRANSMISSION MEANS INCLUDING A TUBULAR PILLAR OF INSULATING MATERIAL SUPPORTED BY THE CYLINDER OF EACH FLUID PRESSURE ACTUATOR, AN INSULATOR ROD EXTENDING THROUGH THE PILLAR AND CONNECTED TO THE PISTON OF THE ASSOCIATED CYLINDER AND ROCKING LEVER MEANS BETWEEN THE INSULATOR ROD AND THE MOVABLE CONTACT MEMBERS FOR EQUALIZING THE STRESS COMMUNICATED TO THE MOVABLE CONTACT MEMBERS BY THE INSULATOR ROD, AND MEANS CONTROLLED BY EACH PISTON FOR RELEASING AUTOMATICALLY THE PRESSURE FLUID IN THE INTERIOR OF THE CYLINDERS WHEN ONE OF THE PISTONS MOVES PAST THE FIRST POSITION AWAY FROM THE SECOND POSITION.

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