US2330820A

US2330820A - Electric circuit breaker with compressed fluid blowout

Info

Publication number: US2330820A
Application number: US287348A
Authority: US
Inventors: Fernier Bernard Marie Hil Paul
Original assignee: Individual
Current assignee: Individual
Priority date: 1938-07-30
Filing date: 1939-07-29
Publication date: 1943-10-05
Anticipated expiration: 1960-10-05
Also published as: CH218205A; FR858497A; BE435718A

Description

Oct. 5, 1943.

B. M. H: P. FERNIER ELECTRIC CIRcUlT BREAKER lwml COMFRESSE'D FLUID BLow ouT l Filed 4.my 29, 1939 Engl.

2y sheets-sheet 1 MMM Oct. 5,1943; B. M. H. P. FERMER 42,330,820

ELECTRIC CIRCUIT BREAKER WITH COMPRESSED FLUID BLOW OUT Filed' July 29. '1939 2 sheets-sheet 2 .[3/ /2 '//1 C 'lll VIIIIlllIl/IlllllllllllllllIlIlllll Patented Oct. 5, 1943 ELECTRIC CIRCUIT BREAKER. WITH COM- PRESSED FLUID BLOWOUT Bernard Marie Hilaire Paul Fernier, Lyon,

France; vested in the Alien Property Custodian Application July 29, 1939, Serial No. 287,348 In Germany July 30, 1938 Claims.

This invention relates to electric circuitbreakers and more particularly to those which themselves supply the energy required for blowing the arc.

Circuit-breakers which themselves supply the energy required for blowing the arc generally comprise means for storing up potential energy during the operation of closing the contacts and then deliver said energy on separation of the contacts to impart to the fluid for blowing the arc a certain degree of pressure. Compressed air is generally used to blow the arc. The potential energy referred to is predetermined for a given type of apparatus. When the intensities of the short circuit currents to be broken exceed a certain value, the type of circuit-breaker referred to can no longer be used, as it then becomes necessary to supply supplementary energy from a source outside or apart from the circuitbreaker.

One of the objects of the present invention is to provide an electric circuit-breaker with compressed fluid blow out and which supplies its own energy for blowing the arc, in which the rupturing power is increased. With this object in view the circuit-breaker in accordance with the invention contemplates the production by said circuitbreaker of a supplementary quantity of energy over and above a given intensity of current which passes through the arc at break, said supplementary quantity of energy being supplied from a different source from the latter for effecting the blow out.

In accordance with the invention the two quantities of energy referred to may act simultaneously or else said supplementary energy acts first and produces a preponderating blast, the blast produced by the other quantity of energy not beginning to act until some time after said former quantity.

The invention has other aims and objects in addition to those above set forth, all of which will be readily understood from the following description taken in connection with the accompanying drawings of embodiments of the invention herein given for illustrative purposes, the true scope of the invention being more particularly pointed out in the appended claims.

Fig. 1 shows an illustrative embodiment of the invention;

Fig. 2 is a longitudinal section of that part of the circuit-breaker containing the fixed contact and the two auxiliary contacts, and illustrates, upon a larger scale, the means for obtaining a concentric ow of the air currents;

Fig. 3 illustrates certain modications of the apparatus shown in Fig. 1;

Fig. 4 shows further modifications;

Figs. 5, 6, 7 show the cam 3 in three principal positions.

Referring to Fig. l there is therein represented partly in elevation and section and partly in per spective a circuit-breaker of the general type described comprising an air compressor having a piston operated by a. spring and tensioned before the closing of the contacts of said circuit-breaker, said spring being capable of Storing up in advance the energy required for the closing and separating of said contacts as well as the energy required to produce the compressed air required for blowing the arc.

In said figure the compressor piston l is connected on the one hand to the free end of a powerful spring 2 and on the other hand to a cam 3 which is operated by mechanism herein shown in perspective for the sake of elearness. A shaft 4 of this mechanism is directed perpendicularly to the plane of said figure and its projection is shown at 4 which designates the axis of oscillation of the cam, which is moved by said mechanism in a contra-clockwise direction. In the course of this rotarx7 movement it can engage and` carry with it a roller 5 upon one arm of a bell crank lever 6 which controls the main movable contact 1 of the circuit-breaker, the fixed contact of which is indicated by 8. These two contacts draw an are herein called the principal arc and designated by 9. Said circuit-breaker is further provided with an auxiliary fixed contact lll and an auxiliary movable contact Il which, when the intensity of the current to be broken exceeds a given value, draw an arc herein called the auxiliary are and designated by I2 and which is struck in series with the main arc (or principal arc).

In this figure the circuit-breaker is shown with its arc drawing contacts separated, the action of the cam 3 on the movable contact I then being as follows. Said cam has a iull portion 3a and a cam groove 3b. When said cam engages said roller 5 said full portion 3a causes the lever 6 to swing clockwise about its fulcrum thus closing said principal contacts 1 and 8. With the circuitbreaker being thus in circuit closing position, said roller 5 is opposite the entrance of said cam groove 3b. The separation of said two principal contacts takes place by a further rotation of said cam 3 in the course of which said roller 5 leaves said cam groove 3b. The details of this operation will appear more fully below. The auxiliary movable contact li is operated by a bell crank lever i3 against the action of a spring I4 which tends to keep the auxiliary contacts IB and II separated. These two cont-acts are kept in closed position by a heil crank lever l5, one arm of which is opposite the movable core of an electric relay I6 which is energized by the main current passing through the circuit-breaker.

The tensioning of spring 2 to store up energy to closeI and then to separate the contacts or the circuit-breaker and to blow the" principal arc, is4

effected as follows:

Rotation of the shaft i on whichis splined the cam 3 is eiiected by a crank I'lfwhich by means of an endless screw device i3 ofwhich the wheel is loose upon said shaft, and a lever I9 actua-tes a driving member 2B carried bysaid shaft. When in its contra-clockwise rotation said cam brings its end 3a opposite said roller 5, said spring 2 will be tensioned and a pawl 2l engages a bell crank lever 22 ofv which one arm is opposite'the movable core of a winding' 23 adapted to venect closing movement of the contacts ofthe circuitbreaker'. Furthermore, bythe tensioning movement of said spring 2 an inclined plane 24 is moved to act upon a roller 25v carried-by a bell crank lever 25 and thus through a suitable connection swinging said bell crank lever I3 contraclockwise about a iulcrum to close the auxiliary contacts I0, II, said lever I3 engaging said bell crank lever I5.

Closing movement of the principal contacts 'i and 3 of the circuit-breaker is effected by sending an energizing current through the winding 23 which causes the movable core of the latter to swing the bell crank lever 22 about its fulcrum thus freeing the pawl 2i. Said'shaft 4 lis thus unlocked, and under the' action of said spring 2, said cam 2 isv rotated counter clockwise and rotatesl said shaft il. vDuring this time the part 3a of said cam Sfcauses bell crank lever 6 to swing clockwise about its fulcrum to close the principal contacts l and il; When saidy contacts are thus closed, pawl 2l engages bell vcrank lever 2l, one arm of which is opposite themovable core of a winding or coil 2t adapted to effect the separation of said principal Contact.

To effect an ordinary separation of said contacto an energizing current issent through said coil 22. The resulting movement of its coil rotates said lever 2l and disengagessaid pawl 2 i. Shaft el` being thus unlocked, cam 3 is caused t'o rotate contra-clockwise by spring 2 which` was only partially distendedv during the closing movement of said principal contacts. However the principal movable Contact does not immediately start its movement as the roller' 5 passes along the cam` groove 3b from which it is not yet freed. During this time the air'at the left of. piston I is pushed back through a hollow insulator 29 which support'sa part oi the circuit-breaker and into a chamber 3d in which is located the principal nxed contact '8; so as not to effect the separation of said two principal contacts until the air pressure ior blowing the arc has reached its most efficient value. As the roller. leaves said cam groove 3b thus liberating said lever 6` the latter swings contra-clockwise under the action of 'spring' 3i, and thus separates said principal contacts l and t. and the principal arc 9 is blown by the compressed' air which continues to blow through said chamber 30, driven by the pist'on'l which reachesl the endv ci its stroke under the action oi spring f2. v

In accordance with the invention supplementary energy for the blast is borrowed from the auxiliary arc. To this end contacts Iii and II are located within a chamber 3i preferably separated from the chamber 3B containing the principal fixed contact as above set forth. The gases generated by said auxiliary arc i2 as well as the air within said chamber 3l the pressure of which is increased to a very high degree by the heat generated by said auxiliary arc, are blown against the principal arc 9, either directly or after contacting with a name shield 32 by which they are cooled, the blast thus furnished being of an intensity proportionate to the intensity of the current to be interrupted.

In accordance with the invention also said auxiliary arc I2 forms before the principal arc when the intensity of the current to be interrupted exceeds a certain intensity value. To this Yend means are provided herein comprising a relay i6 which operates instantaneously but cnly when said intensity value is exceeded, the coil 28 for separating the contacts being supplied with current by a relay 33 the operation or" which is retarded.

When the intensity of the overcharge current to be interrupted is inferior to said intensity value above referred to, the relay 33 alone operates and said coil 2S causes separation of the arc drawing contact as above setl forth. On the other hand when the intensity of the current to be interrupted exceeds said intensity value, said relay I5 operates immediately to free said lever I3 which under Ythe action of said spring le separates said auxiliary contacts. Furthermore said lever i3 in turning about its iulcrum acts upon'the lever 25 to cause the latter also to turn and move the core of` said coil 28 through a suitable link connection 3e. The lever` 2l is thus freed and the principal contacts 1, 8 start to separate but only when said roller 5 has escaped from said cam groove 3b, that is to say after a certain time has elapsed and after separation of contacts It) and il.

To the blast produced by said auxiliary arc I2 there is therefore added that produced by piston i. To facilitate this the currents oi compressed air produced by said arc I2 and said piston are directed against the arc 9 along parallel courses. As shown in Fig. l, said two air currents are concentric.

SaidV two compressed air currents act simultaneously and thus combine their blowing action. The blast from piston i continues after extinction of the arcs S and I2., thus scouring the space between and about the principal contacts l and 8 and precluding any restriking of the arc.

The invention contemplates the use of any suitable arrangement to produce the concentric flow of said two compressed air currents. In the illustrative embodiment of the invention this result may be obtained by using a principal iixed contact which is hollow and the hollow interior of which communicates with the compressor cylinder as shown in Fig. 2. This gure is a longitudinal section of that part of the circuitbreaker containing the principal xed Contact the two auxiliary contacts the remainder of said circuit-breaker having the same arrangement as that shown in Fig. 1. Referring to'Fig. l a channel 35 leads from an insulator 29 and conducts the air propelled by piston I into the interior space 36 of said mainixed contact 8.

The interior chamber of the hollow xed principal contact may communicate with the chamber in which the auxiliary arc is formed. Such an arrangement is shown in Fig. 3. As in the `case of Fig. 2 so also in the case of Fig. 3, only that part of the circuit-breaker containing the principal fixed Contact and said auxiliary contact is illustrated, the remainder of said circuitbreaker being of the same construction as that shown in Fig. l. The principal and auxiliary contacts as well as the arcs struck thereby are indicated in said Figs. 2 and 3 by the same reference characters as in Fig. 1. In Fig. 3, the interior chamber of the hollow fixed contact 8 communicates with the chamber 3| in which the auxiliary arc is struck and the concentric chamber 38 of said hollow contact communicates with the air `compressor which is diagrammatically indica-ted by said piston 39.

In accordance with the invention a certain degree of simultaneous action of the two compressed air currents referred to may be obtained by directing said currents in opposite directions against said arc 9 'as shown illustratively in Fig. 4. In

vthe illustrative embodiment shown in said ligure the operation of the main and auxiliary contacts and the generation of the air blast may be and, as is herein shown, are identical with those illustrated in Fig. 1. The corresponding means have been omitted from Fig. 4 in order not unnecessarily to complicate the drawings, only the piston I, the driving spring 2, the lever 5 for ,operating the principal movable contact 1, that part of the circuit-breaker containing the principal xed contact 8 and the auxiliary contacts, as well as the particular means .and features to be considered have been shown diagrammatically in order that the invention may be clearly understood. The compressed air heated by the auxiliary arc is conducted to the fixed contact 8, while the air driven by the piston I is conducted through said hollow insulator Z9 into a cylinder 40 in which said movable contact 'I operates. The gases and the compressed air produced by the arc I2 are directed against that point of attachment of the arc 9 which is within the chamber 4I while the blast of compressed air from the piston I is conducted through openings or ports provided in a partition 42 and into a pipe 43 surrounding the movable contact, whence it directed against the other point of attachment of said arc 9.

The energy for the blast generated by said auxiliary arc and that produced by the compressor may act successively. In that case the blast generated by said auxiliary arc, which always preponderates, starts rst and operates alone. The blast from the compressor starts to operate later and adds its operation to that generated by said arc; it scours the space separating and surrounding the contacts 'and completes the blowing of the arc, thus precluding any restriking of the latter. Any one of the farms of circuit-breakers above described. may be provided with a resistance serving to delay the re-establishment of the tension. Said resistance may be applied either mechanically or pneumatically and will preferably shunt the 'auxiliary arc and, the case arising, the principal arc. When the intensity of the current (short circuit) t0 be cut is weak, the interruption of said current is effected without the insertion of said resistance by using only the blast produced by the compressor. When however said intensity becomes considerable the arc of the auxiliary contacts produces a blast and inserts or throws said resistance 8l into operation. The current which remains for the principal contact to cut is therefore only a current the intensity of which has been reduced by said resistance.

A capacity may be substituted for said resistance in all the circuit-breakers of the latter type and said capacity may be rendered operative either mechanically or pneumatically and will preferably shunt the auxiliary arc and the case arising the principal arc.

The compressed air blast produced by the compressor cylinder may not only act simultaneously with that supplied from the chamber in which the auxiliary arc is struck but may also act after the arc has been extinguished. This has the advantage that the space about the contacts is efficiently and thoroughly scoured, any restriking of the arc being thus precluded. This operation takes place automatically in the majority of the apparatus above described, by causing the principal contacts and the auxiliary contacts to move at a suitable regulated speed and by making the compressor plant of suitable dimensions.

Among the many advantages possessed by apparatus embodying the present invention may be mentioned the increase in the rupturing power of the usual circuit breakers which themselves compress the air required for blowing their arcs, as well as the possibility of regulating the intensity of the arc-extinguishing blast proportionally to the intensity of the current to be cut, and the fact that small arcs can be extinguished as well as larger arcs.

I am aware that the present invention may be embodied in other` specic forms Without departing from the spirit or essential attributes thereof, and I therefore desire the present embodiments to be considered in all respects as illustrative and not restrictive, reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

I claim:

l. Electric circuit breaker with compressed fluid blow out, comprising, in combination, relatively movable main arc-drawing contacts; relatively movable auxiliary arc-drawing contacts mounted in series with said main arc-drawing contacts; a chamber for said main arc-drawing contacts; a separate chamber for said auxiliary aro-drawing contacts; mechanism for opening and for closing said main arc-drawing contacts; mechanism for opening and for closing said auxiliary arc-drawing contacts; fluid compressing mechanism operatively connected tothe arc-drawing contact closing mechanism; means for rendering said auxiliary arc-drawing Contact opening mechanism operative to open said contacts only when and after the current to be cut reaches a certain intensity, and before the main contacts are opened; means to direct a blast of compressed fluid against the main arc from said fluid compressing mechanism; and means to direct a blast of compressed iluid against said main arc 'from the chamber of said auxiliary arc.

2. Electric circuit breaker with compressed fluid blow out, comprising, in combination, relatively movable main arc-drawing contacts; relatively movable auxiliary arc-drawing contacts mounted in series with said main arc-drawing contacts; a chamber for said main arc-drawing contacts; a separate chamber for said auxiliary arc-drawing contacts; mechanism for opening and for closing said main arc-drawing contacts; mechanism for opening and for closing said auxiliary arc-drawing contacts; fluid compressing mechanism, including a piston operatively connected to the arc-drawing contact closing mechanism;

:means`V for rendering said 'auxiliary arc-drawing contact opening mechanism operative to open said auxiliary contacts only when and after the current to be cut reaches a certain intensity, and before the main contacts are opened; rneans to direct a blast of compressed fluid lagainst the main arc from said duid 'compressing mechanism; and means to direct a blast of compressed iiuid against said main arc from the chamber of said auxiliary arc.

3. Electricv circuit breaker with compressed iiuid blow out, comprising, in combination, a fixed main arc-drawing Contact; a chamber containing said Contact; an inclosure for said chamber, terminating in an exhaust mouth-piece for the compressed duid blast; a movable main arcdraWing contact adapted to be Withdrawn out- Wardly from said chamber and said inclosure to draw an are; relatively movable auxiliary arcdrawing contacts mounted in series with said main arc-drawing contacts in a second chamber near that containing said fixed main arc-drawing contact; mechanism for opening and for closingsaid main arc-drawing contacts; mechanism for opening and for closing said auxiliary arc-drawing contacts; a cylinder provided with a piston to provide compressed fluid Within the circuit breaker, said piston being operatively connected to said arc-drawing contact closing mechanism; means for rendering said auxiliary arcdrawing contact opening mechanism operative `to open said auxiliary contacts only when and after the current to be cut reaches a certain intensity, and before the main contacts are opened; means for conveying compressed uid from said cylinder into said chamber containing said fixed main arc-drawing contact; and means for conveying-compressed fluid from said chamber containing said auxiliary arc-drawing contacts between said chamber containing said nxed main contact and said exhaust' mouth-piece.

' 4. Electric circuit breaker With compressed fluid blow out, comprising, in combination, a iixed main arc-drawing contact; a chamber adapted to contain said contact and terminating in an exhaust mouth-piece for the compressed uid blast; -a movable main arc-drawing contact adapted to be withdrawn outwardly from said mouth-piece; a tube mounted opposite said mouth-piece and in alignment therewith to receive said movable contact when it is Withdrawn I from said mouth-piece; relatively movable auxiliary arc-drawing contacts mounted in series with said main arc-drawing contacts, in a cham, bei` near that containing said fixed main arcdrawing contact; mechanism for opening and for closing said main arc-drawing contacts; mechanism for closing said auxiliary arc-drawing contacts; a cylinder containing a piston to furnish compressed duid in the circuit breaker, said piston being operatively connected to the arc-drawing contact closing mechanism; means adapted to open said auxiliary arc-drawing contacts only when and after the current to be cut reaches a certain intensity and before the main contacts are opened; means to convey the fluid compressed by said auxiliary arc into said mouthpiece, and means to convey fluid compressed by said cylinder into said tube, the main arc thus receiving a blast of compressed fluid from said mouth-piece and a blast of compressed uuid from said tube.

5, Electric circuit breaker with compressed fluid blow out, comprising, in combination, relatively movable main arc-drawing contacts; a chamber containing said contacts; auxiliary arcdrawing contacts mounted in a chamber separate from that containing said main arc-drawing contacts and in series With the latter; mechanism for closing said main arc-drawing contacts and said auxiliary arc-drawing contacts, the mechanism for closing said main arc-drawing contacts including a cam for closing the latter; mechanism for opening said main arc-drawing contacts and for opening said auxiliary arc-drawing contacts; a cylinder and piston to provide compressed duid in the circuit breaker, said piston being operatively connected to the arc-drawing contact closing mechanism, the piston rod being connected to the mechanism for closing said auxiliary arc-drawing contacts; an electric relay to render said auxiliary arc-drawing contact opening mechanism operative to open said aiuriliary contacts only when and after the current to be cut reaches a certain intensity and before said main arc-drawing contacts are opened; means to direct a blast of compressed fluid against the main arc from said cylinder; and means to direct a blast of compressed fluid against the main arc from said chamber of said auxiliary arc.

BERNARD MARIE HILAIRE PAUL FERNIER.