US2100757A - Circuit breaker - Google Patents

Description

Mm w3? wmm fd WM5 CIRCUIT BREAKER Filed Sept. 29, 1954 5 ShseS-Sheet l 73 7' f WITNESSES; Im/ENTOR Lu 10mm' NOV 30 w37- I R. H. swsNGLE -2 SF CIRCUIT BREAKER l/ NES/SES: INVENTR' ATTORNE Patented Nov. 30, 1937 UNITED STATES PATENT OFFICE y CIRCUIT BREAKER Pennsylvania Application September 29, 1934, Serial No. 746,255

22 Claims.

My invention relates generally to circuit interrupters and is particularly concerned with circuit breakers of the type used forlcontrolling distribution feeder and lighting circuits.

In the past, it has been rather common practice to provide fuses or fuse and switch arrangements for protecting circuits of this type. These devices were not entirely satisfactory, however, due' to the undesirable discontinuities of service which resulted when the fuses melted, and in addition, the arrangements were somewhat dangerous, particularly when it became necessary for an inexperienced individual to replace a blown fuse.

In order to obviate these dilculties, circuit breakers of suitable rating have been devised for use in protecting this type of circuits. Circuit breakers have numerous advantagesV over the older fuse or fuse and switch combinations: they are inherently safe, being capable of opening large amounts of power without serious or damaging arcing; and what is more important, they'may be reclosed, after they have opened the circuit following the occurrence of an overload, by any person however inexperienced, without danger and without the inconvenience of securing a new fuse.

In the type of service under consideration, the load usually consists of lights, appliances, or small motor-operated devices. These devices frequently develop faults either in the internal insulation or in the insulation of the cords or other means used for connecting them into the circuit, a common example being the failure of an electric iron cord.

Ii such a fault occurs on a circuit which is protected `by a fuse or a standard type circuit breaker the immediate result is to cause either the blowing of the fuse or the opening of the breaker. All power is removed from the circuit and there is no rWay of determining exactly where the fault condition exists. Usually the housewife or operator of the machine, as the, case may be, inserts another fuse without removing the faulty apparatus from the line, with the result that the fuse again blows or the circuit breaker again opens. The danger incident to the blowing of the fuse is, oi course, obviated when a breaker is used, but even in this case it has been necessary yto goto the point where the `breaker is located and reciose it.

It would appear that the solution of the problem lies in the provision of a circuit breaker, suitable for use in circuits oi the type under consideration, which will automatically open the circuit so as to prevent damage to the line or supply equipment upon the occurrence of overloads or abnormal circuit conditions, and which will. automatically reclose itself when and only when the fault conditions are removed from the controlled line, and to provide such a breaker is the principal object of my invention.

Another object of my invention is to provide a circuit breaker of this type which shall be provided with a movable operating member for permitting both manual and automatically controlled movement of the breaker contacts to the open or to the closed-circuit position.

A further object of my invention is to provide a circuit breaker of the type mentioned in the principal object which shall be simple and inexpensive to manufacture, and which shall be safe and reliable in operation.

A still further object of my invention is to provide a circuit breaker which shall be snapacting in either direction, which shall open the controlled circuit upon the occurrence of excessive overloads or other abnormal conditions, irrespective of the position of the operating member, and which shall be provided with means for effecting the automatic reclosing of the contacts immediately following the removal of the overload or abnormal conditions in the controlled circuit.

In carrying out these objects of my invention, I provide a circuit breaker which utilizes a snapacting mechanism of the toggle-linkage and over-center spring type. 'I'he mechanism includes means for cooperating with an electroresponsive tripping element in order to effect the opening of the breaker upon the occurrence of overload or\ fault conditions, and in addition, it is provided with a magnetically responsive means for reclosing the contacts following each opening of the breaker, which results from the operation of the electro-responsive trip device, after the fault condition has been remedied.

In one form of my invention, the electrical circuit through the breaker is never entirely opened, but when the contacts are moved to the opencircuit position a current limiting impedance or a transformer is automatically inserted into the circuit in order to limit the amount of current which may flow in the controlled circuit. In another form, the contacts of 'the breaker are movable through three positions; the normal open and the normal closed-circuit positlomto which the contacts may be moved by actuation ofthe operating member, and a tripped position to which the contacts are moved automatically upon the operation `of the electro-responsive means. Both of these forms include magnetic means, which are responsive to the conditions in ,the controlled circuit, for eecting automatic reclosing of the breaker mechanism.

Through this arrangement, I provide a device which eectively protects the circuit from any damage which might result, due to an overload or other fault condition, and at the same time, i" provide a device which is automatically operable to restore the circuit to its normal condition immediately following the removal of the faulty apparatus or the like. Thus, when a defective piece of apparatus is connected into the circuit the immediate effect is to produce an opening of the breaker and the limiting of the amount of current which may ow in the circuit. Y This con- I dition becomes immediately apparent to the user by virtue of the extinguishment of the lights or by the stopping of other equipment connected to the same line and all that is necessary for that person to do in order to restore the "line to its rnormal energized condition is to remove the deiective piece of equipment from .the line by pulling out its attachment plug or turning o its switch, whereupon the breaker automatically restores itself to the normal position. The convenience of such an arrangement and -its desirability, particularly when used in homes or similar places, is apparent.

Another desirable feature which arises from my improved circuit vbreaker is that the location of faulty equipment is greatly facilitated, it being merely necessary, when investigating a faulty circuit having a large number of pieces of connected equipment, to remove each piece sucbodies the principal features of my invention;

Fig. 2 is a sectional view, similar to Fig. 1,

showing the circuit breaker illustrated in that gure in the normal open-circuit position;

Fig. 3 is a sectional view, similar to Figs. 1 and 2, showing the circuit breaker in the tripped position;

Fig. 4 is a sectional view taken on the .line IV-IV of Fig. 1;

Fig. 5 is a fragmentary, perspective view showing certain of the details of the operating mechanism used in the breaker illustrated in Figs. l through 4;

Fig. 6 is an enlarged, fragmentary view of the operating mechanism shown in the other figures of the drawings at the instant just preceding the automatic reclosing of the contacts;

Fig. 'I is a sectional view taken on the line VII-VII of Fig. 1;

Fig. 8 is a diagrammatic view of the electrical atours? 3, a movable switch arm 5 for cooperating with the main stationary contact, an operating mechanism l for moving the switch arm 5 to the open and to the closed-circuit position, a solenoid means 9 for eecting the reclosing of the breaker, and an electro-responsive element it', which is adapted to cooperate with the operating mechanlsm 'l so as to effect the automatic opening of the breaker on the occurrence of predetermined conditions. A resistance, transformer, or other impedance means I3 is likewise supported on the base I, and is so connected in the electrical circuit through the breaker (see Fig. 8) that it limits the amount of current whichmay flow therethrough during the existence of a fault or other abnormal condition in the controlled circuit. The various structural elements of the device are enclosed by means of a suitable cover I5, likewise of molded insulating material, which is held in position on the base I by a screw Il.

` The switch arm 5 comprises a U-shaped frame I9, having rearwardly extending portions 2|, a spring support 23 for the movable contact 25 lwhich engages the stationary contact 3 when the breaker is in the closed circuit position, and a exible shunt 2l for connecting the support arm 23 with the terminal member T2. The switch arm is pivotally supported through the agency of a pivot pin 3i upon a U-shaped frame 29 which is bolted to the base I.

The operating mechanism 'l is supported upon a frame member 33 which is aiiixed tothe base l by means of four-cap screws 35. It includes a pair of toggle links 3l and 39, an operating member 5I, and over-center spring Q3 intermediate the toggie links and thel operating member, and a cradle i5 for, so supporting the upper end of the toggle linkage that the operation of the bimetallic electro-responsive element II will cause the opening of the breaker, irrespective of the position of the operating member 4I. l The lower toggle link 37 has a bifurcated endI portion which pivotallyengag'es the frame I9 of the switch member 5 through' the agency of a suitable pin di. The upper portion of this link is pivotally connected to the lower end of the other toggle link 39 by means ofthe knee pivot connections of the breaker shown in- Figs. 1l

through 7; and

Fig. 9 is apdiagrammatic view of the electrical connections of a modified form of the breaker of the over-center spring 43.

pin e9. This pin, as is' shown particularly in Fig. 7, has a reduced portion 5i for engaging one end The upper end of the toggle link 39 is pivotally fastened to the cradle member 45 by afpin 53, that member being,

Ain turn pivotally supported on the frame 33 of the operating mechanism through the agency of asupport pin 55.

The operating member 4I is pivotally supported on the main frame 33 by means of a pair of short pivot pins 51 which engage suitable openings in the U-shaped lower portion 59 of that member.

A. molded insulating member comprising a handle portion 6I and a shield portion 63 is affixed tothe closed end of the U-shaped portion of the operating member in order to permit manual movement thereof. 'I'he central v portion of the U-shaped member 59 has 'a knife edge65 (shown particularly in Figs. 5 and 6) formed integral therewith for engaging the upper end of the over-center operating spring 43. The molded handle portion 6I extends through an opening 62 in the cover I5 which opening is substantially closed at all times by the shield portion 63. The lower end of the right-hand side (Fig. 7) of the` U-shaped portion 59 of the operating member isfprovided with a cam section 66 for effecting the reclosing of the breaker, as will be explained in some detail-later.

A latch l' is plvotally supported upon an arm 69 extending from one side of the main frame 33 and is biased in a counter-clockwise direction by means of a suitable coil spring 1i. This latch holds the movable contact in the tripped posi.- tion during the reelcsing operation, in orde-r that the deenergization of the magnetic reclcsing means Q shall not be aiected before the entire mechanism has been restored to the normal opu erative position.

The magnetic reclosing means 9 consists simply of a suitably supported attracting solenoid 73. a cooperating armature 'l5 and a link 'l1 for mechanically connecting the armature and the operating member di. The particular design of the solenoid and armature is not an important part of my invention and 4any suitable arrangement may be used.

An auxiliary contact member 19 is supported upon the central tie portion 8l of the main operating frame 33, and this member is adapted to be engaged by the upper surface of the moving contact 25 when the breaker ls in the tripped position. The auxiliary contact 'IS is insulated from the frame 33 by means of a pair ci insulating members 83 and is electrically connected to the attracting solenoid 13 oi the magnetic reclosing means by means of a conductor 85. The other end ofthe attracting solenoid is electrically connected to the terminal Tl by a suitable concluctor 81.

The bimetallic, thermally responsive clement I i is of U-shaped design such as is* shown in Patent No. 1,862,758, issued to 0. S. Jennings on April 28, 1931, and is rigidly supported on'the base l of the interruptor by means of a pair of screws 89. The upper end of the element il terminates in an outwardly projecting metallic member Si which is adapted to cooperate wtib the outer end 93 of the cradle 45, so as to restrain that member from moving under the iniluence of the biasing action of the over-center spring 43. c

The electrical circuit for the preferred embodiment of my invention is shown schematically in Fig. il. The terminal Tl is adapted to be connectenl to one side ci the line and to one side ci vthe load, and internally of the breaker, is connected to one end of the reclosing solenoid, as mentioned above. The other line lsconnecteci to the terminal Td, which' in turn, is connected. to one end of the current carrying, bimetallic thermallyresponsive element il and by conductor it to one end of the current limiting resistance l. The other end oi the bimetallic element Il is connected by conductor i2 to the stationary Contact 1 3, and the other e'nd oi the resistance 1t is ccn-1 nectecl to the terminal T2. The switch arm d and the associated moving Contact 25 are likewise conc nected by conductor it to the terminal Tt.

From this it will be seen that when the' breaker is in the open-circuit position the load is ccnnected to the line through the current-limiting resistance it. VThis resistance may, of course, be adjusted to any desired value.

When 'the break-er is in the closed-circuit position the load is directly connected to the line by means of the circuit through the terminal T2, the moving contact the stationary contact d, the bimetallic tripping element il and the terminal Tt?. It will be noted that the resistance i3 le short-clrcuited by the contacts and the bimetal- -lic element i l.

When the breaker contacts are moved to the tripped position, as a result or the actuation of the bimetal, the rccloslng solenoid it is connected. directly across the load and the load is connected to the line through the current limiting resistance i3, the bimetallic element Il being entirely removed from the circuit. So long as the fault or other abnormal condition exists on the load. circuit, the voltage drop across the reclcsing solenoid 'it will be very low and practically no current will flow therethrough. However, when the fault condition is removed from the load circuit, and the resistance of that circuit is returned to its normal value, the voltage drop across the reclosing solenoid 13 will be greatly increased, and by a proper selection of the coil and the resistance, may be caused to eiectsufiicient energization of the solenoid to make possible the reclosing of the breaker.

The operating mechanism l and the breaker contacts are shown in the closed-circuit position in Fig. i. To open the contacts manually, the operating member 4l is moved in a clockwise direction, thereby bringing the line of action of the over-center spring 43 to the right o! the line connecting the centers of the upper toggle link 39. As soon as this occurs, the mechanism reaches an unstable condition and the toggle linkage collapses to the position shown in Fig. 2, thereby effecting the opening of the breaker contacts with a snap-action. Movement oi the switch arm toward the open-circuit position is definitely limited by the engagement of the projecting portion 95 of the upper toggle link 39 with the member Sl which connects the two side portions of the frame 33. The distances are so adjusted that the moving contact 2l does not engage the auxiliary contact l!! nor does it become latched-in when the switch arm moves to the open-circuit position due. to movement of the operating handle.

To close the breaker manually after a manually produced opening operation, the operating member il is moved in a counter-clockwise directlon from the position shown in Fig. 2v, thereby bringing the line of action of the over-center spring 63 to the lett o1' the line connectingthe centers of the upper toggle link 39. This causes the contact arm to be moved to the closed position shown in Fig. l with a snap action. The circuit breaker or my invention may therefore be used as a snap-acting switch for normally opening and closing the circuit by manual operation oi the handle.

When the breaker is in the closed-circuit position shown in Fig. l and an overload or other fault condition occurs in the controlled circuit,

the excess current c-wlng through the bimetal- V lic thermally responsive element il causes the upper ond of that member to be moved so as to disengage the portion 9i from the outer end lill of the cradle. When the breaker is in the closedcircuit poaition, the reaction forces of the cvercenter oec-rating spring 43 bias the cradle 45 in a counter-clockwise direction, and as soon as the cuter end dii of that member is released by the bimetallic element. the cradle is free to rotate from the position chown in Fig. l to the position shown in Fig. 3.

This rotation taires place at high speed and effects a very rapid separation ci the currentcarrying contacts. In addition, as a result of the displacement of the toggle linkage which is effooted by the rotation of the cradle 45, the stop el is not'efective and the moving contact 25 moves in a clockwise direction until it engages the auxiliary contact 19 and simultaneously be comes latchecl against that contact by the latch member Si,

let

.as pointed out above, the movement of the breaker mechanism to the tripped position in response to an overload serves to connect the reclosing solenoid 'i3 across the load and so long as the fault condition persists in the controlled circuit, the energization of that solenoid is insufficient to effect the reclosing of the breaker. However, as soon as the fault condition is removed, the armature l5 of the reclosing means is attracted toward the center of the solenoid i3 and the resulting movement causes the operating member lili to rotate from the position shown in Fig'. 3 to the position shown in Fig. 6. The latch tl causes the contacts 25 and il@ to remain in engagement during this movement, thereby assuring that the solenoid will not be deenergized before the reclosing operation is complete.

As the operating member di is moved by the reclosing solenoid i3, the cam portion of that member engages the edge of the bifurcated portion of the lower toggle link 3l (as shown particularly in Fig. 6) and causes that link to rotate in a. clockwise direction. Since the switch arm 5 is prevented from moving by the latch @l this l rotation of the lower toggle link til is transmitted through the other toggle ,link 3d to the cradle member d, causing that member to rotate in a clockwise direction. The surfaces of the cam portion @E are so correlated with the other parts of the mechanism-that the cradle member is rotated to the normal closed-circuit position before the operating handle di has reached its limit of motion in the counter-clockwise direction, thus, shortly before the cam action is completed the end S3 of the cradle it is reengaged by the latching portion @l of the electro-responsive element il.

Veryfshortly after the cradle i5 is relatched, the latch tl is released by the engagement of a projecting member 96 forming a part of the operating handle li, with a suitable cooperating projection 98 formed integral with the latch itself. At this instant, the over-center spring il@ is tensioned so as to bias the toggle linkage toward the normal closed-circuit position, and immediately following the release of the switch arm 5 by the latch Bl, the breaker moves to the closedcircuit position at high speed.

It will thus be seen that the reclosing operation not only recloses the breaker following (and only following) the removal of the fault or other abnormal condition from the controlled circuit, but at the same timeit restores the several parts of the operating mechanism to the normal operating position, thereby allowing the contacts to be moved to the open and to the closed-circuit position in the usual manner by movement of the operating member. The breaker is thus entirely automatic and substantially fool-proof.

It should also be noted that the circuit breaker distinguishes between an opening of the contacts manually by the handle and'automatically in response to an overload. When the breaker is opened by manual movement of the handle, the reclosing solenoid is not connected in the circuit so that the breaker remains open, as was intended by the operation until it is again man.- ually closed; but when the breaker is opened due to the ow of an excessive current, the reclosing solenoid is connected in the circuit and the .breaker is automatically reclosed as soon as the condition causing the excessive current has been remedied.

For certain applications, .it may be desirable that the electrical circuit through the breaker amarsi? shall be entirely opened when the contacts are in the normal open-circuit position. If this is necessary, it may readily be effected through the prcvisionLof a second auxiliary contact normally insulated from the first auxiliary contact but adapted to be connected to that contact when the breaker is in the tripped position. Such an arrangement is shown in Fig. 9, and it will be seen that this breaker differs from that previolrrly described only through the addition of an extra contact member ibi, to which the resistance i3 is connected. in this modiiied structure, the electrical circuit through the breaker is opened when the breaker is in the open-circuit position, and it is closed through the bimetallic electro-responsive element il when the breaker is in the closed-circuit position. When the breaker is in the tripped position, the electrical circuit is closed through the current limiting resistance or other impedance i3 and, as in the previously described structure, the reclosing solenoid i3 is directly in parallel with the load thereby assuring that the reclosing mechanism will not become operative until the overload or other fault condition is removed from the connected circuit.

From the foregoing, it will be seen that I have disclosed a new and improved form of circuit breaker which is particularly suitable for use with circuits which are frequently subjected to overload or other abnormalv circuit conditions. My improved device includes the desirable feature that it is snap-acting in both directions for normally opening and closing the circuit, and that itis operable upon the occurrence of an overload or other abnormal circuit conditions to automatically open the circuit through the breaker,

irrespective ofthe position of the operating handle, so as to prevent injury to the supply or other equipment. Further, my improved breaker includes means for automatically reclosing itself, and for restoring itself to a normal operative position, following each opening operation which results from the actuation of the electro-responsive means. Moreover, the automatic reclosing means is so designed that it will not effect the reclosing of the breaker until the fault condition is removed from the controlled circuit.

In addition to showing how a circuit breaker might be built embodying the above-described desirable features, I have shown how those features may be incorporated into a breaker similar to those in commercial use at the present time, thereby reducing the expense of embodying the features of my invention into commercial apparatus to a minimum.

While I have shown only a single-pole breaker, it is, of course, within the province of my invention that a multipole structure could be used, and it is obvious to one skilled in the art thatlnumerous modications and combinations of the invention may be worked out without departing from the broad principles disclosed. It is also possible, and probable, that various other forms of operating mechanisms may be utilized for accomplishing the objects of the invention. It is my intention,

therefore, that the language of the accompanying claims shall be construed as covering such devices, and that my invention shall 'be limited only by what is expressly stated in those claims and by the prior art.

I claim the following as my invention:

1. In a circuit interrupter, separable contacts for opening and for closing the electrical circuit through said interruptor, actuating means for said separable contacts including an operatingr meinten :notatie to normally nasse sait?. contacts to move einen to the open. oi' to the oiosesin circuit position, eleetouresnonsive means opern aiole noon the occurrence oi predetermined conoitions the oiionit to cause said actuating means to move saiei contacts to the onenv eirouit position, anti. means operable only after saiol Contacts have been moved to the open-oiieoit position as resiiit of the actuation of said eleotioiesnonsive io for oaiising said aotuating means to retLLo inteiiufpteid automatically to the closedoii'onit position upon the removal of the canse oi neoeteiinined oonitions in the circuit.

an antoniatiealiy ieciosing circuit iorea tei', eontaot movable to an open and to a oloeeiimoii'cuit position, aetnating means for said. oontaot means inoin fie: an operating member is inovalnie en two positions to Cause Contact ineens to moved to the open to tlie oloseiii'ouit,position, eleoti^o-responsive 'means operable upon the oeonrence oi piecieteiw niineoi conditions in the oiiouit to cause said actuu means to nieve Contact means to the onen-circuit position, ano means for causing said actuating means to automatically reoiose said contact means ioliotving each opening operation qa/"iuiefi is caused by said emette-responsive means,

saio means causing automatic ieolosing being "E tintin istenoe of tiie cause oi nl s ied conditions and when saisi een ai'e moved to the openoii'ouit position by QlosedHoiTC'oi-t positie Ineens ineii geredet a Means foi automatie. reolosing Fp oil only opening operations f Wi i* canse by saisi eieeti'oa'esnonsiie messo and unen immensi the canse of otenet iininefi a eiioiiit in e itei, oontaot ineens moi7u aioie to an open a o, to a eioseduoiiouit position, said means inoiuding i operating* n'ieintie which. is niovaoie between :lo positions to canse saisi contact means to be to open to the oioseei-oiio" t position, eleotiooesnonsive means oneraoie nnen tile of an aiinoniai oondition in the conE tiolied oiieuit to said aotuating means to nieve saisi oontaot means to the open-circuit position, means fos causing said actuating means to antoniatioaiiy return said contact means to the W olosefi-eii'ouit position ioiiowing eao'n opening operation which is caused by the operation of said eeotrowresponsive means, said means o eieotiiig the automatic reclosng of said. inter motel being" operable only after those opening open'ations which result from the opera-tion of saici electro-responsive means and, in addition, being opeiabe oriiy after the abnormai condition in the controlled circuit has been removed.

5 in a. circuit interruptor, Contact means mov@ URS.

asie to an onen and to a oloseiiqeiionit position, astiiating means for said oontaot' means .eindm ing an operating n'ieinbeii which is moi/asie loe- -een two 'positions to Cause saici Contact means to "oe moved. to tiie onen oi' to the olosed-foifonit position., eleotiooesponsive 'means operable upon the occoirence oi an abnormal oonslition in the oontiolleel circuit to eause said actnating means to move said Contact nieans to the onen-siiout position independently oi the position oi saisi operating membei, and means for Causing actuating means to automatioaily ieoiose said oon-tast means following eaoo. opening onei'ation which is caused by said eleotioofesnonsive means for causing antoinatie ieeiosing being operable oniy when tiie aonoinia. eonoition removed from the oontroied strooit and, afl-iim tion, being operable oniy when senayation said Contact means has been oanseel by tile egiei' ation of said eleotioHiesponsii/e means.

5. in a oii'ouit inteirupter, eontaot means niet# asie to an open and to a olosed-oiiooit goositioa, actuating means for said oontaot means ineiuol= ine' an opeating ineinoei which is moi/als e to cause saioM Contact means to moved. to boi'ii open and the closed-ciieuit position Witn a snap action, electro-responsive means, opesable noon tne ooouienoe oi? predetermined ooi ditions,

oaose said actuating ineans to move s wit-n snap action, means g ine set/nen sa i anton to tile oies i sans site ineains, salti foi efieoting eoften`I` io ieeiosing said ntei beine operable o y after t'nose open.-1

ing-opeiations Winch ies'olt from tile opei'ation of said eieoti'o=iesoonsive means in addition. being operable only site? saisi nieoeteisminec oonoitions have ceasefi to exist.

:in incultinteiinjotei, contaet ineens movaieie to an open ane to a dosed-circuit position, actuating means fof said contact means inclini.-z ing an over-oeiitei` serine' means and an oneatina member, Wlfiio'i is inova'oie to cause said over center spring means to move sain Contact means from one nos tion tothe other with a snai. action., eleoti'o-esponsive means operable upon tiie oc ourrence oi? piedeteiinineii conditions in the oil'- euit to cause said actuating means te move saici Contact means to the open-circuit position, iike- Wise with. a snap action, ano. means for causing i essere? condition iollowing cach opening operation which is caused by the operation of said electro-respony sive means.

9. In a circuit interruptor, contact means movable to an open and to a closed-circuit position, actuating means for said contact means, including an over-center spring means, a toggle. linkage, and an operating member, said operating member being movable to cause said contact means to be' moved from one position to the other with a snap action, electro-responsive means operable upon the occurrence oi predetermined conditions to cause said actuating means to move said contacts to the onen-circuit position, and means, which is operable only aftersaid contacts have been moved to the open-circuit position as a result ci the actuation of said electro-responsive means, for causing said interruptor to return automatically to tl'ie closed-circuit position.

l0. In a circuit interruptor, contact means movable to an onen and to a closed-circuit uosition, actuating means for said contact means including over-center spring means, and an operating handle, said operating handle being movable to cause said contact means to be moved from eacl'i position to the other with a snap action, electro-responsive means operable upon the occurrence of an abnormal condition in the controlled circuit to cause said actuating means to move said contact means to the open-circuit position with a snap action independently of the position of said operating handle, and means for causing said actuating means to return said contact means automatically to the closed-circuit position following each opening operation which is caused by tbe operation ci said electro-responsive means, said means for effecting automatic reclosing o.' said interruptor being operable only after those opening operations which result from the operation ci? said electro-responsive means and, in addition, being operable only after the abnormal condition in the controlled circuit has been removed. y

il.. in a circuit interruptor, separable contacts -ior opening and for closing the electrical circuit to cause said actuating means to move said coni tacts to the open-circuit position, and magnetic means which is energized in response to conditions in the circuit controlled by said interruptor for causing said actuating means to return said interruptor automatically to the closed-circuit position following and only following each contact opening operation which is caused by said electro-responsive means.

12. 1n a circuit interruptor, contact means movable between two positions, actuating' means for said contact means includingan operating member, a contact operating link, and an overcenter spring intermediate said operating membei' and said contact operating link, said operating member being movable between two positions to cause said contact operating link and said contact means to be moved trom one position to the other with a snap action, electro-responsive means operable upon the occurrence of predetermined Vabnonmal conditions to cause Said attuate ing means to move said contact means to tireA open-circuit position, and magnetic means op'erable ior causing said actuating means to return said contact means automatically to the closedcirouit position following and only following each contact opening operation wlieh'is caused by said electro-responsive means.

13. In `a circuit interruptor, contact means movable between an open and a closed-circuit position, actuating means for said contact means,

, including an operating member, a toggle linkage,

and an over-center spring intermediate said operatinv member and said toggle linkage, said operating member being movable between two `positions to cause said contact means to be moved from one position to the other with a snap action, electro-responsive means operable upon the occurrence of predetermined abnormal conditions to cause said actuating means to move said contact means to the open-circuit position with a snap action independently or the Luosition of said operating member, and magnetic means for causing said actuating means to return said contact .means automatically to the closed-circuit position following each opening operation which' is caused by said electro-responsive means, said means for eecting automatic reclosing being operable to efiect the reclosing of said contact means onlywben the abnormal condition is removed irom the controlled circuit and, in addition, being operable only when the separation of said contact means has'been caused by the operation of said electro-responsive means.

lll. In, a circuit interruptor,l a contact member movable to an open-circuit position, to a closedcircuit position, and to a tripped position dierent from said onen-circuit position, actuating means for said contact means, including an operating member movable betvieen two msitions to cause said contact 'member tomove to tbe open and to the closed-circuit position, electro-responthe'tripped position, and means operable only when said contact member has beenV moved to the tripped position to cause said actuating means to return said contact member automatically to the closed-circuit position.

l5. In a circuit interruptor, contact means. aetuatingmeans therefor movable to an onenoircuit position, to a ciosed-circuit position, and to a tripped position, said actuating means 'including an operating member movable to cause said contact means to move to the open and to the closed-circuitV position, electro-responsive means operable upon the occurrence of predetermined abnormal conditions to cause said actuating means to move to the tripped position, and means for causing said actuating means to return said contact means automatically to the closedcircuit position following each operation of the actuating means to tripped position, said means for effecting automatic reciosing oi said contact means being operable only when said actuating means have been moved to the tripped position, and in addition being operable only after the abnormal condition in the controlled circuit has been removed. y v

i6. 1x1 a circuit interrupter, contact means, actuating means therefor movable to an opencircuit position, to a closed-circuit position, and

to a tripped position, said actuating means iuyic means to move to the open-circuit and to the closed-circuit position with a snap action, electroresponsive means operable upon the occurrence of a predetermined abnormal current condition in the circuit controlled by said interrupter to cause said actuating means to move to the tripped position and thereby cause said contact means' operating member movable between predetermined positions for operating said contact member to open and closed positions, a movable carrier for said operating mechanism, an electroresponsive element for releasably retaining said carrier in a latched position, said carrier being movable from the latcbed position to a tripped position in response to a predetermined abnormal current condition for causing said operating mechanism to move said Contact member to a tripped position, electro-magnetic means operable when said contact member is in the tripped position for automatically actuating said operating mechanism to smuentially operate said carrier to its latched position and said contact member to its closed position, means for retain- "f .ing said contact member in the tripped position until said carrier has been moved to its latclied position, and current limiting means operative While said contact member is retained in the tripped position for causing a limited current to iiow through tile circuit, and said electro-maa'- netic means automatically'actuating the operating mechanism in response to a predetermined change in said limited current.

in a circuit controlling device. separable contacts, actinrtina means ior said separable contacts movable to open, closed and tripped p sitions, said actuating,1 means including handle means for moving contacts between open and closed positions, electro-responsive means operable upon tice occurrence ci predetermined conditions for causing said actuating means to be moved to tire tripped position, impedance means connected in the circuit ior'causing a reduced current to flow through the device vflien in tripped position. and means responsive to' a change in tire flow oi said reduced current tbrouab device nnen said actuating means is in the tripped position only for automatically causing movement of said actuating means to tire closed position.

lain a circuit controlling device, Senf-arable contacts, act a ing for said separable contacts movable to op closed and tripped posio tions, said actuating means including operating means for causing said contacts to normally open and close tire electrical circuit through tl'ie device "when moved to opened and closed positions respectively, electro-responsive means operable upon tine occurren oi predetermined conditions for causing said actuating means to be moved to the tripped position, means for causing a reduced current to ilovv through the circuit oi tne device when in tripped position, and means responsive to the flow of said reduced current through the device when said actuating means is in the tripped position only for automatically causing movementI of said actuating means to the closed position, said last-named means causing movement of saidv actuating means to the closed position only upon the removal of said predetermined conditions.

' 2G. in a circuit controlling device, a. fixed conv tact, a movable contact, means for actuating said movable contact to open and closed positions with respect to said xed Contact, said movable contact also being movable by said actuating means to a tripped position, a second fixed contact adapted to cooperate with said movable contact to establish an electrical circuit through said movable and said second fixed contacts when the movable contact is in the tripped position, electroresponsivemeans operable upon the occurrence of predetermined conditions ior causing said actuating means to move said movable contact to the tripped position, means connected in circuit only by said movement to tripped position for causing iiow oi current through the circuit controlled by the device, means for causing said actuatins means to automatically move said movable contact from. the tripped position to the closed position in response to a change in said current which flows when said movable contact is in tripped position.

2l. 'in a circuit controlling device, contact means, actuating means including manually operable means for normally causing said Contact means to open and close the circuit and electroresponsive means for causing said contact means to open the circuit upon the occurrence of a predetermined condition in the circuit, impedance means connected in shunt across said contact means when said Contact means have been caused to open by said current responsive means for causing a reduced control current to ovfin the circuit, means for causing opening of the circuit of said impedance means when said contact means is caused to open by said manually operable means, and means responsive to said reduced control current for causing reclosure of said contact means.

22. .in a device for connecting a load to a line, main contact means by which said connection is made, actuating means including manually 'operable means for normally causing opening and closing oi said main contact means and electroresponsive means for 'causing opening of said main contact means upon the occurrence of a. predetermined condition, impedance means connected to the line side oi said main Contact means ior causing a reduced control current to flow to tile load "when said main contact means have been caused to own by said current responsive means, means for disconnecting said impedance means iro-in the line upon the opening of said main contact means by said manually operable means, and means responsive to said reduced control current for camina reclosure ci said man contact means.

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