US2154703A

US2154703A - Circuit interrupter

Info

Publication number: US2154703A
Application number: US40194A
Authority: US
Inventors: Jerome M Sandin
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1935-09-12
Filing date: 1935-09-12
Publication date: 1939-04-18
Anticipated expiration: 1956-04-18

Description

April 18, 1939. J. M sANDiN rncUIT INTERRUPTER' Filed Sept. l2, 1935 5 Sheets-Sheet l l N VEN TOR //ome M50/vdi?.

ATTO R N E v 4WITNESSES: I PZ/Q.

April 18, 1939. v J, M SANDIN 2,154,703

cIRcUl'T INTERRUPTER Filed Sept. 1 2, 1935 '3 Sheets-Sheet 2 WITNEssEs; /25 37 6 INVENTOR ferome/W50na//h TTORNEY Patented Apr, 1s, 1939 UNITED STATES PATENT OFFICE 2,154,703 n omoUrr rNTEaaUPTEa `lerome M. Sandin, Forest Hills, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application September 12, 1935, Serial No. 40,194

` (ci. zoo-9s) 30 Claims.

sign has always presented a rather complexy problem to the art. Due to the large amounts of available power which may be fed into the circuit upon the occurrence of fault conditions, it is necessary, to give adequate protection to the controlled equipment, that the breakers shall 15 be capable of interrupting large amounts of power within very short intervals ,of time. Further, since the devices are ordinarily operated by more or less inexperienced persons, it is imperative that they shall be absolutely safe and 20 reliable in operation. 4 v

In order to prevent undesirable'discontinuities in service while at the same time providing satisfactory protection of -the controlled circuits and the connected equipment, it is necessary that 25 the' breakers shall be capable of distinguishing between prolonged overl'oads and those of a transient nature. In addition, vit is necessary, in certain installations, that the equipment shall be -responsive to abnormal voltage conditions and 30 that it may be actuated by remotely disposed control means of the relay or other type.

In contrast with these operational require--v ments, it is absolutely imperative that the physical vdimensions of these breakers shall be kept within certain deilned limits, in order to permit their use in existing panelboard and other switch structures. In addition, it is necessary that the initial cost of the breakers shall not be excessive, due to the'large `numbers which 40 are used on even a small system or network, and it is desirable that the breakers shall be easy to service in order to minimize maintenance costs. The provision of a breaker which is capable of meeting all oi' these requirements con- 45 stitutesthe principal object of the present invention. x w,

One form of breaker which has met with considerable success in the past utilizes a single standardized contact structure and actuating mechanism for arather wide range o;-r current values, the rating of any particular breaker being vdetermined by the provision of a suitable trip'device. The closure for these breakers comprises a cooperating base and cover, preferably 55 formed of molded insulating material. By means 4extends across all of the poles thereof and is 10 of suitable ribs and partitions in the multi-pole forms, a separate space or chamber is provided for each ofthe poles. The movable contacts i'or the several poles are mechanically tied together so as to move as a unit,l and a single operating mechanism, normally disposed in one of the pole spaces, is utilized for actuating all of the contacts.

The trip device for the multi-pole breakers adapted to engage and be retained within a suitable recess formed in the cooperating cover and base. The device includes tripping means operable in response to predetermined electrical conditions in the circuit controlled by each of 16 the poles of the breaker. By making the trip device readily interchangeable with other similarly proportioned device, it is possible to market a whole line of breakers built up around the single, standardized, contact structure and actuating mechanism.

For most installations, it is necessary to provide but two tripping means for each of the poles of the breaker, one a thermally responsive element operable after a predetermined time delay upon the occurrence of a prolonged moderate overload to effect the operation of the trip device and the other operable substantially instantaneously upon the occurrence of predetermined large magnitude overloads. In other installations, it is also necessary to provide under-voltage A77tripping means, shunt tripping means, and similar arrangements. The incorporation of auxiliary devices of these latter types into the known forms of circuit breaker and trip devices through the utilization of the unoccupied portion of the pole chambers constitutes a further object of the present invention.

Another object of the invention consists in 'the provision of means for cooperating with the 40 .actuating mechanism for controlling the operation of auxiliary tripping devices.

A further object of the invention is to provide a removable trip device interchangeable with similar devices of like or diiferent rating for controlling the operation of circuit breakers which may be calibrated and sealed at the factory and to which, at the option of the user, may be added additional tripping means or other auxiliary devices without necessitatlngthe opening of the closure for the trio device, with the accompanying danger that the calibration thereof might be changed.

A still further object of the invention is to provide an interchangeable trip device of the type which includes a separate sealed closure for the movable portions thereof and which is removable as a unit from cooperative engagement with the associated breaker mechanism with non-adjustable tripping means adapted to operate in conjunction with the normal tripping means of the breaker. Ihese additional tripping means to be disposed without the closure of the trip device.

An ancillary object of the invention is to provide an improved shunt; trip element and an improved under-voltage trip element for a circuit breaker trip structure of the type -under discussion, and to provide a simple means for controlling the operation of such devices in response to the operation of the associated breaker actuating mechanism and contact structure.

'I'hese and other objects will be ymade more apparent by reference to the following drawings and descriptions of certain preferred embodiments of the invention. Referring particularly to the drawings:

Figure 1 is a plan view of a three-pole circuit Ibreaker wherein are embodied the features of the invention. The cover of the breaker has been almost completely cut away in order to more clearly illustrate the various structural elements.

Fig. 2 is an enlarged sectional view taken on the line II-II of Fig. 1.

Fig. 3 is a fragmentary View of the trip device and a portion of the operating mechanism of the breaker illustrated more completely in Figs. 1 and 2.

Fig. 4 is an enlarged sectional view, of the trip device shown in the other gures of the drawings. The view is taken on the line IV-IV of Fig. 3.

Fig. 5 is an enlarged view of the shunt trip element forming a part of the trip device shown particularly in Figs. l'and 2.

Fig. 6 is a sectional view on the line VI-VI of Fig. 5.

Fig. 7 is a view corresponding to Fig. 6, showing the features of the under-voltage trip element forming a part of the trip structure shown particularly in Figs. l and 2.

Fig. 8 is an enlarged fragmentary view, partially in section, of the operating linkage utilized in conjunction with the under-voltage trip element,

. and

Fig. 9 is a fragmentary enlarged view of the trip bar and portions of the bimetallic thermally responsive trip elements forming a part of the trip device proper. Y

The circuit breaker illustrated particularly in Figs. 1 and 2 is, as mentioned above, of the three pole type. The base I upon which all of the structural features of the breaker are mounted is formed of molded insulating material and is provided with suitable ribs or partitions 3 formed integral therewith for separating the three poles. l

The cover 5 is likewise formed of molded insulating material and is provided with cooperating ribs 1, as is shown particularly in Fig. 2, for engaging the similarly disposed ribs 3 in the base.

In the completed structure, these ribsl or parti-

l tions

3 and 1 serve to dene three chambers which have the substantial form of rectangular prisms and which are spaced side by side.

Six terminals 9, three of which are affixed to either end of the base by means of suitable bolts II provide a means whereby the breaker may be connected into an electrical circuit. The electrical circuit through each of the poles of the breaker is substantially the same. A rigid strap member I3 of conducting material, preferably copper, serves to support each of the stationary contact members I5 and to connect those members with the adjacent cooperating terminal 9. A

movable contact member I1 pivotally supported.

formed of laminated material is electrically and mechanically connected to the rear end of each of the movable contacts I1, and each oi these ilexible conductors 23 terminates in a solid terminal member 25 which is adapted to cooperate with one of the terminals 29 of the breaker trip device 21.

As is shown particularly in Figs. 1 and 2, the l trip device 21 is provided with six of these terminals 29, two for each of the poles of the breaker. Each pair of the terminals 29 is electrically interconnected within the device itself by a looped conducting strip 3|, formed of laminated l material, which serves as an energized heater for the thermally responsive trip element and as an energizing coil for the magnetically responsive trip element associated with each of the poles of the trip device. Each of the upper terminals "29 of the trip device 21 is afiixed to one of the block terminal members 25 by means of a pair of screws 33 and each of the lower terminal members is in turn afxed to one of theterminals 9 oi the breaker by a pair of the bolts II. Thus, the conducting strip 3| interposed between each of the pairs of terminals of the trip device serves to complete the electrical circuit for each of the poles of the breaker from the terminal member 25 to the lower breaker terminal 9.

Each oi' the contact supporting frames I9 vis bolted to a square tie member 35, comprising a steel core and an outer sheath of insulating material, in order to permit the simultaneous actuation of the contacts. A single operating mechanism 31 is/provided for simultaneously actuating the contacts.

The contact supporting frame I9 for the central pole has a link member 39 cast integral therewith, and this link member is pivotally supported upon the frame 4I of the actuating mechanism 31 by a suitable pivot pin 43, the pin 43 thus serving to support the entire assemblage of interconnected movable contacts. 'I'he operating mechanism 31 is preferably of the type disclosed in the copending application of Harry J. Lingal, Serial No. 637,749, filed October 14, 1932, which became Patent No. 2,083,305 on June 8, 1937 and which is assigned to the assignee oi' the present invention. As illustrated in Fig. 2, the

mechanism includes a pair of toggle links and 41, an operating member 49, an over-center spring 5I intermediate the operating member and the toggle links for causing those links to move from the normal closed circuit position shown in Fig. 2 to a collapsed open circuit position, or vice versa, in response to movement of the operating member 49. One end oi the interconnected toggle links is supported upon a cradle member 53 which is normally retained in the position shown in Fig. 2 by a trigger member 55 adapted to engage and cooperate with the trip device 21. The trip device normally retains the trigger member 55 in the position shown in Fig. 2, and when the trigger is in that position the actuating mechanism 31 is operable in response to movement of the operating handle 49 to move the interconnected movable contacts |1 to the open and to the closed circuit position.

Upon the actuation of the trip device, the trigger member 55 is released, and it moves aut'cmatically to a position where it causes the actuating mechanism 31 to eilect the opening of the breaker, independently of the position of the operating handle 49. By virtue of the overcenter spring construction, the contacts are at all times moved to the open, to the closed and to the tripped position, (which is substantially the same as the open position) with a snap action.

'I'he various structural elements of the trip device 21 are mounted uponl a separate base member 51 which is adapted to engage a suitable recess 59 formed withinr the cooperating base and cover which comprise the breaker closure. The device includes a latch 5|, which is shown particularly in Fig. 4 forengaging and retaining the trigger member 55 of the breaker actuating mechanism in its normalr operative position, a trip bar 52 movable from a normal inoperative position to an operative position to release the latch 5| and effect the operation of the tn'p device, a plurality of thermally responsive, trip elements, each of which is energized in response to the current ow in one of the poles of the breaker, and a plurality of magnetically responsive trip elements each of which is likewise energized in response to the current flow in one of the poles of the breaker. of the thermally responsive trip elements and each of the magnetically responsive trip elements is individually operable upon the occurrence of predetermined conditions to move the trip bar 52 from the normal inoperative position, shown in Fig. 4, to a position where it causes the latch member 5| to release the trigger member 55 and thus effect the opening of the breaker. The trip bar 52 is pivotally supported at either oi' its ends upon suitable bracket members 55 ailixed to the base 51 of the trip device and extends across all three of the poles of the breaker. It is biased to its normal position by a suitable spring 51 and since the latch 5| is also biased to the normal latched position, the trip device is automatically prises a tapered strip of bimetallic material 58 `which is supported at one end thereof upon a U-shaped frame member 59, the frame member being, in turn, bolted to the base 51 of the trip device. 'Ihe looped portion of the laminated conductor 3| disposed between each of the pairs of terminals 29 of the trip device extends along 'the bimetallic member 58 and is affixed to the lower end thereof and to the supporting U-,shaped frame 59 therefor by means of a pair of rivets 1|. The upwardly extending portion of the bimetallic element 58 is provided with an adjustable screw 13 for engaging the trip bar 62.

Each of the magnetically responsive elements includes a U-shaped core member I5 supported upon the adjacent U-shaped frame 89, and a slidably supported armature 11 biased away from the cooperating core member 15 by a pair of springs 19. The core member is energized by current iiow through the associated looped conductor 3|, and the springs 19 are so adjusted that movement of the armature takes place only following the occurrence of predetermined severe overload conditions. The trip bar 52 is provided with three downwardly projecting members 8| one of which is disposed in the normal path of Each movement of each of the armatures 11, in order that movement of the armatures may be transmitted to the trip bar. Thus, the trip bar may be moved from the normalinoperative to the tripped or operative position by the bending of any one of the bimetallic elements 58 or by the movement of y any one of the slidable armatures 11 from the unattracted to the attracted position.- A support bracket 83 is rigidly afllxed to the base 51 of the trip deviceat the central portion thereof, and this bracket is provided with a pin 84 adapted to engage a suitable recess 85 formed in the block terminal of the central pole in order to accurately position the4 trip device 21 with respect to the other features of the breaker mechanism. This bracket 83 also serves to support and accurately position the trip latch 5|.

A removable cover 85, formed o'f molded insulating material, is provided for enclosing the various structural features ,l of the trip device. This cover is normally supported upon the brackyets 55 by means of suitable screws 81 and these screws are preferably sealed in position by a seal 88 as is shown in Fig. 3, during the manufacture of the device, in order to prevent unauthorized persons from tampering with the calibration of the trip elements.

In addition to the above-mentioned thermally responsive and magnetically responsive trip elements, the device shown in the drawings is further provided with a shunt trip element 9| and an under-voltage trip element 93. Each of these elements is supported upon the base 51 of the trip device by means of a, suitable bracket member 95 and a pair of bolts 91, and each is readily removable therefrom without necessitating the removal of the cover 85 of the trip device. The bracket members '95 are so arranged that they support the under-voltage and the shunt trip elements a substantial distance away from the base 51 of the trip device and thereby assure that theaddition of either or both of these elements shall in no way interfere with the removal or replacement of the trip device by` preventing free access to the removable screws 33 utilized for connecting the trip device into the breaker structure.

'Ihe shunt trip element 9| is shown particu--l larly in Figs. 5 and 6. It includes a 4U-shaped core |8| of magnetic material rigidly amxed to,

' or formed integral with, the supporting bracket 95. An iron pole piece |83 is screwed into a suitable recess formed in the outer end of this Ufshaped core |8|, and a brass tube |85 which serves as a guide vfor the movable armature 81 of the element engages a suitable supporting shoulder formed in this pole piece. The inner end of the brass tube |85 is retained in position -Y by a cap member |89 which serves the further function of providing a stop for the armature. The armature |81 is cylindrical in form and is provided with a hollow cylindrical recess formed in the outer end thereof for positioning a suitable biasing spring Ill. The coil means 3 for energizing the pole piece of the device is disposed about the brass tube |85 and is insulated from metallic portions of the device by an insulating spool'li 5. A tie-rod ||1, preferably of insulating material, is aillxed to the inner end of the armature |81 and is provided with a C- shaped member ||8 for engaging one of the projections i9 forming a part of the trip bar 52. This rod and the C-shaped trip bar engaging member ||8 move within a suitable hole |2| formed within the base 51 of the trip device. The

-oi strap conductors |21 disposed within suitable recesses formed therein, and a third strap member |29 for -bridging the members |21. The bridging member |29 is supported for movement into and out of bridging engagement with the straps |21 by means of a slidable rod member |3| oi' insulating material having a head |33 formed integral therewith. This insulating support memfber |3| is biased to the closed circuit or bridging position by means of a spring |35 and is adapted to be moved so as to open the electrical circuit through the switch by the engagement of an L-shaped member |31 ailixed to the contact supporting frame I9 for the outer pole. Through this arrangement, the electrical circuit through the energizing coil I3 for the shunt trip element 9| is opened at two points, immediately upon the movement of the breaker contacts to the open circuit position, and any danger of the coil being burned out is thereby eliminated.

The under-voltage trip element 93 is shown particularly in Fig. 7. Similar to the shunt trip element 9|, it includes a U-shaped frame 20| of magnetic material formed integral with the supporting bracket 95 therefor. The pole piece 203 is threaded into the inner side of the U-shaped frame 20|, as contrasted with the pole piece |03, due to the diil'erence in the direction of movement of the armatures. The armature 201 is cylindrical in form, is provided with a suitable biasing spring 2|4 for directing it away from the pole piece 203, and-is adapted to move within a brass tube 205 ordinarily retained in abutting engagement with a shoulder formed in the pole piece. by an outer cap member 209. The amature 201 includes an inwardly extending rod 2|l adapted to operatively engage the tie rod |I1 and the C-shaped member ||9 which comprise the trip bar engaging means, substantially the same as for the shunt trip element. A suitable voltage responsive energizing coil 2|3 serves to retain the armature 201 in the position shown in Fig. 7 except when the energizing voltage falls below a predetermined minimum value.

In order to assure that the Yarmature of the under-voltage element shall be moved into contact with the cooperating pole piece following each operation of the breaker, a mechanical linkage means is provided for interconnecting the armature with the breaker contact assemblage. This linkage includes a rigid metallic member 22| aixed to the supporting frame |9 for the right-hand movable contact member, an insulating link 223, and a spring plunger means ailixed to the armature 201 itself. 'Ihe plunger means comprises a rod member having an enlarged outer portion 229 and an inner portion 23| of reduced area upon which a washer 233 is adapted to slide, this washer being normally biased against the shoulder formed by the enlarged outer end 229 by'a suitable spring 235. The intermediate link 223 has a cylindrical guide opening 231 of somewhat largerdiarneter than ythe outer end 223 to assure the movement of the rod member therein, and when the contacts move to the open circuit position, this intermediate member engages the slidable washer 233 and moves that washer to a position where the stress transmitted through the spring 235 is suillcient torestore the armature 201 to its normal position. In this position the impedance of the device reaches its maximum value and burning out of its energizing coil 2|3 upon the restoration of voltage to the energizing circuit is prevented.

The operation of the trip device 21 is believed to be more or less obvious from the foregoing. Upon the occurrence of a predetermined low magnitude overload in the circuit controlled by any one of the poles of the breaker and the persistence of that overload for a predetermined period of time, the bimetallic element 6l, energized in response to the current flow in that pole, is caused to bend and move the trip bar 62 to the operative position. In this position the latch 5| no longer restrains the trigger member 55 in the position shown in Fig. 2 and the trigger member moves automatically to cause the actuating mechanism 31 to eiect the opening of the breaker irrespective.of the position of the operating handle 49. Similarly, upon the occurrence of a predetermined large magnitude overload in the circuit controlled by any one of the poles oi' the breaker, the associated core member 15 is energized sufliciently to attract the cooperating armature 11 and thereby move the trip bar 62 from the normal inoperative to the tripped position.

The thermally responsive and the magnetically responsive trip elements provide complete overload protection for the circuits controlled by the breaker, but they do not give protection against under-voltage or over-voltage conditions nor do they permit remote control of the breaker. These latter functions are accomplished by the shunt trip element 9| and the under-voltage trip element 93. In the shunt trip element the armature is moved magnetically, in the under-voltage element the armature is restrained from movement by an electromagnetic field. Together the elments provide a exible arrangement capable ot meeting all possible requirements.

Both elements may be added to a trip device of the type disclosed in the subject application without ,necessitating the removal of the cover of that device. Factory adjustments and calibrations are thus preserved throughout the operative life of the device. In both elements the armature engages the trip bar only during the latter portion of its movement from the inoperative to the operative position. 'I'his assures positive actuation of the trip bar by permitting the armature to acquire substantial kinetic energy before engaging and moving that member.

The lead terminals 25| of the shunt and undervoltage trip elements are preferably brought out of the breaker closure through suitable holes 253 formed in the side walls of the base member From the foregoing, it will be seen that I have disclosed the features of a new and improved form of electro-responsive trip device, particularly suitable for use with circuit breakers of the type which employ standard operating mechanisms and interchangeable trip structures. In addition, I have disclosed auxiliary tripping means such as under-voltage and shunt trip devices which may be added to known forms of tripv structures without necessitating the removal ol' thecovers of those devices or without neces sitating any substantial alteration in the associated equipment.'

In the preferred form of my invention, I so position these auxiliary tripping means on the base of the trip device that they extend into the space ordinarily left unoccupied when the breaker is in operation, that is, within the excess space in the chambers provided for each of the poles.` This probably is one of the most important features of the present invention because it is only by this novel arrangement that the use of these auxiliaries in conjunction with existing equipment is made possible.y

It will immediately be obvious that my provision loi' auxiliary control means for'tripping devices and my improved arrangement of the structural features of these devices has effected a substantial extension of the useful range of operation of these devices without any accompanying deleterious effects whatsoever. 'I'he resultant trip devices are still readily interchangeable, and their normal operational qualities are in no way effected by the addition of the auxiliary means in accordance with the invention.

Further, I have disclosed certain preferred structural arrangements for accomplishing the other objects ofy the invention, and I have shown how the operation of my improved under-voltage and shunt trip device may be controlled by the operating mechanism and the contacts of the breaker.

While in accordance with the patent statutes, I have, in the foregoing, disclosed the features of certain preferred structural arrangements and embodiments of my invention, it is to be understood that these structures are merely illustrative. Variations in their precise form may and probably will be not only desirable but necessary in many instances without departing from the concept of the invention and it is my desire, therefore, that the language of the accompanying claims shall be accorded the broadest reasonable construction and shall be limited only by what is expressed therein and by the prior art.

I claim as my invention:

1. In a circuit interrupter, separable contact means for opening and for closing the electrical circuit therethrough, actuating means for said contact means, a trip device operable upon the occurrence of predetermined conditions to cause said actuating means to move said contact means automatically to the open circuit position, said trip device being removable from said interrupter as a unit and including a base, a cover which cooperates with said base to define a closure for said device, electro-responsive tripping` means disposed within said closure. and other electroresponsive tripping means supported on said base outside said closure, said last mentioned means y, being removable from operative engagement with said trip device without necessitating the removal of said cover. and means for mechanically interconnecting said last mentioned tripping means with said separable contact means and the actu-` ating means therefor.

2. In a circuit interrupter; separable contacty means for opening and for closing the .electrical circuit therethrough; actuating means` for said I contact means; and a trip device operable upon said closure, and auxiliary tripping means disposed outside said closure; said last mentioned means being readily removable from operative engagement with said trip device without necessitating the opening of said sealed closure, to permit similar means of like or different characteristics to be substituted therefor.

3. A trip device for a circuit interrupter comprising a unitary structure removable as a unit from said interrupter and including a base, a cover for cooperating with said base to define a closure for said device, terminals mounted on said base for releasably connecting said device into the electrical circuit or circuits controlled by the associated interrupter, electro-responsive tripping means disposed within said closure, and auxiliary electro-responsive tripping means supported on said base outside said closure, said last mentioned tripping means being readily removable from and movable into operative engagement with said trip device without necessitating the removal ofsaid cover, to permit similar means of like or different characteristics to be substituted therefor.

4. A trip device for a circuit interrupter comprising a unitary structure removable as a unit from said interrupter and including a base, a cover for cooperating with said base to define a. closure forksaid device, terminals mounted on said base for releasably connecting said device into the electrical circuit or circuits controlled by the associated interrupter, electro-responsive tripping means disposed within said closure, and at least two auxiliary electro-responsive tripping means supported on said base outside said closure, one of said auxiliary tripping means including an armature biased to an operative position and electro-magnetic means for restraining said armature is an inoperative position, another of said auxiliary tripping means including an armature biased to an inoperative position and electromagnetic means for moving said armature to an operative position, said auxiliary tripping means being interchangeable with each other and being removable from operative engagement with said trip device without necessitating the removal of said cover to permit similar means of like or different characteristics to be substituted therefor.

5. In a circuit interrupter; separable contact means for opening and for closing the electrical circuit therethrough; actuating meansfor said 'contact means; a trip device operable upon the occurrence of predetermined conditions to cause said actuating means to move said contact means automatically to the open circuit position; said trip device being removable from said interrupter as a unit and including a sealed closure, electroresponsive tripping means disposed within said closure, and at least two auxiliary electro-responsive tripping means disposed outside said closure; one of said auxiliary tripping means including an armature biased to an operative position and electro-magnetic means for retaining said armature in an inoperative position; another of said auxiliary tripping means including an armature biased to an inoperative position, a current-carrying attracting coil for moving said armature to an operative position, and a switching means electrically connected in series with the circuit through said attracting coil; said auxiliary tripping means being interchangeable .with each other and being 'removable from operative engagement with saidtrip device without necessitating the opening of said closure, to permit similar means oi' like or different characteristics to be substituted therefor; and means for mechanicallyinterconnecting said auxiliary tripping means with said contact means and said contact actuatingmeans, in order that the amature of said first mentioned auxiliary tripping means shall be restored to said inoperative position in response to each openingmovement oi said contact means resulting from movement of that armature to said operative position, and in order that the operation of said switching means forming a part of said last mentioned tripping means shall be caused to take place in response to movement of said contact means.

6. Ina multi-pole circuit interrupter; a base; a cover for cooperating therewith to define a closure for said interrupter; conducting means including a plurality of pairs of separable contacts for defining the plurality of poles of said `interrupter; means for dividing said closure into a plurality of separate chambers, one for each of said poles; the conducting means for each of said poles being ydisposed in one oi' said chambers; a single actuating means for a plurality of said pairs or separable contacts, said actuating means being disposed within one of said pole chambers;y

and a trip device operable\to cause said contact actuating means to move said plurality of pairs of separable contacts automatically to the open circuit position, said trip device being disposed within said .closure for said interrupter and removable from said closure as a unit, said unit including a separate closure, electro-responsive tripping means disposed 'within said separate closure, and other electro-responsive tripping means disposed without said separate closure; said last mentioned tripping means being readily removable from operative engagement with said trip device, without necessitating the opening of said separate closure, to permit similar means of like or dierent characteristics to be substituted therefor, and being adapted to extend into one or more of said chambers when said trip, device is in the normal operative position within said'main closure.

7. In a multi-pole circuit interrupter; a base; a cover for cooperating therewith to define a closure for said interrupter; conducting means including a plurality oi pairs ,of separable 'con--v tacts for defining the plurality of lpoles of said interrupter; cooperating partition or rib members formed integral with said base and said cover for dividing said closure into a plurality of separate chambers, one for each of said poles; the conducting means for each of said poles being disposed in one o1' said chambers; a single actuating mechanism for said plurality of pairs of separable contacts, said actuating mechanisml being disposed within one of said pole chambers; and a trip device operable to cause said contact actuating means to move said plurality of pairs of separable contacts automatically to the open circuit position, said trip device being disposed in a suitable recess'iormed Within said closure for said interrupter and removable therefrom as a unit, said unit including a separate, sealed closure adapted to extend across said pole chambers adjacent one of the ends thereof, electro-responsive tripping means disposed within said sealed closure, and auxiliary tripping means disposed without said sealed closure; said auxiliary tripping means being readily removable from operative engagement with said trip device, without necessitating the opening of said sealed closure, to permit similar means of like or diierent characteristics to be substituted therefor and being adapted to exf tend into one or more ci said pole chambers when said trip device is in the normal operative position within said closure for said interrupter.

8. In a multi-pole circuit interrupter; a base;

a cover for cooperating therewith to detine a closure for said interrupter; conducting means including a plurality of pairs of separable contacts for dening the plurality oi.' poles of said interrupter; cooperating partition or rib members formed integral with said base and said cover -for dividing said closure into a plurality of separate chambers, one for each of said poles; the conducting means for each of said poles being disposed in one of said chambers; a single actuating mechanism for said plurality oi' pairs of separable contacts, said actuatingv mechanism being disposed within one oi said pole chambers; a trip device operable to cause said contact actuating means to move said plurality of pairs oi separable contacts automatically to the open circuit position, said trip device being disposed in a suitable recess formed within said closure for said interrupter and removabletherefrom as a unit. said unit including a separate closure adapted to extend across said pole chambers adjacent one oi the ends thereof, electro-responsive tripping means disposed within said closure, and auxiliary tripping means disposed without said closure; said auxiliary tripping means being adapted to extend into one or more of said pole chambers when said trip device is in the normal operative position within said closure for said interrupter; and means for mechanically connecting said auxiliary tripping means with said separable contacts and said contact actuating means, said connectingmeans including means movable in one or more of said pole chambers. n

'9. In a circuit interrupter, separable contact means for opening and for closing the electrical circuit therethrough, actuating means for said contactmeans, a trip devicey operable upon the occurrence of predetermined conditions to cause saidactuating means to move said contacts automatically to the open circuit position, said trip device being removable from said interrupteras a unit and including a base, a cover which cooperates with said base to deiine a closure for said trip device, electro-responsive tripping means disposed within said closure, and other electro-retripping means inoperative when the contacts are in the open position.

10. In a circuit interrupter;4 separable contact means for opening and for closing the electrical circuit therethrough; actuating means for said contact means; a trip device mounted at one end of said actuating means and operable to cause said actuating means to move said contact means automatically to the open circuit position; said trip device being removable as a unit from operative engagement with the other elements of said interrupter and including a base, a cover which cooperates with said base to define a closure for' said trip device, current-carrying electro-responsive tripping means disposed within said closure, and other current-carrying electro-responsive tripping means disposed outside said closure and beside saidy actuating means intermediate said trip device and said separable contact means, and

an auxiliary switching means disposed without said closure and beside said actuating means intermediate said trip device and said separable contact means, said auxiliary switching means being electrically connected in series with the circuit through one of said current-carrying tripping means; and means for effecting the actuation of said auxiliary switching means in response to the opening and the closing movement of said contact and said contact actuating means.

11. In a circuit interrupter; separable contact means for opening and for closing the electrical circuit therethrough; actuating means for said contact means; a trip device operable to cause said actuating means to move said contact means automatically to the open circuit position; said trip device being removable as a unit from operative engagement with the other elements of said interrupter and including an electro-magnetic tripping means which comprises an armature movable. from a normal inoperative to an operative positionu to effect the operationv of said trip device; and resilient connecting means connected between said contact means and the aforesaid armature to permit lost motion between said contact means and said armature and operable, when said contact means is moved to the open circuit position in response to an operation of said trip device caused by movement of said armature to said operative position, to return said armature to said inoperative position.

12. In a circuit interrupter; separable contact means for opening and ior closing the electrical circuit therethrough; actuating means for said contact means; a trip device operable tocause said actuating means to move said contact means automatically to the open circuit position; said trip device being removable as a unit from operative engagement with the other elements of said interrupter and including an armature movable from a normal inoperative to an operative position to effect the operation of said trip device, means biasing said armature to said operative position,'and electro-magnetic means for holding said armature in said inoperative position against the force of said biasing means; said electromagnetic vmeans permitting said` biasing means to movi.l said armature to said operative position following the occurrence of predetermined conditions; and resilient means mechanically interconnecting said movable armature with said contact and said contact actuating means, said resilient means causing said amature to be returned to said inoperative position following each operation of said trip device resulting from movement thereof and permitting said contact and said contact operating mea-ns to continue movement after said armature has reached said inoperative position.

13. In a circuit breaker having separable contact members, actuating means for operating said contact members to open and closed positions and tripping means for causing said actuating means to operate said contact members to the open position upon the occurrence of predetermined conditions, said tripping means comprising the combination with a sealed calibrated trip device removable as a unit from said breaker of an auxiliary trip actuating means, said auxiliary trip actuating means being removable from and replaceable in operative engagement with said trip device without disturbing the seal of the latter.

14. In a circuit breaker having separable contact members, actuating means for operating said contact members to open and closed positions and tripping means for causing said actuating means to operate said contact members to the open position upon the occurrence of predetermined conditions, said tripping means comprising the combination with a sealed calibrated trip `device removable'as a unit from said breaker of 'an aux iliary current-responsive trip actuating element, said element being removable from and replaceable in operative'relation with said trip device without disturbing the calibration of the latter, switching means incircuit with said auxiliary current-responsive trip actuating element, and means operable upon the movement of said contact members for actuating said switching means.

15. In a circuit breaker having separable contact members, actuating means for operating said contact members to open and closed positions and tripping means for causing said actuating means to operate said contact members to the open position upon the occurrence of predetermined conditions, said tripping means comprising the combination with a sealed calibrated trip device removable as avunit from said breaker of an auxiliary current-responsive trip actuating element, said element being removable from and replaceable in operative relation4 with said trip device without disturbing the calibration of the latter, switching means. in circuit with said auxiliary current-responsive trip actuating element, and control means adapted to be actuated by said actuating means for said contact members for operating said switch means to deenergize said auxiliary current-responsive trip actuating element when-said contact members are in the open' position. i

16. In a circuit breaker having separable contact members, actuating means for operating said contact members to open and closed positions and tripping means for causing said actuating means to operate said contact members to the open position upon the occurrence of predetermined conditions, said tripping means comprising the combination with a sealed calibrated trip device removable as a unit from said breaker of an auxiliary current-responsive trip actuating element, said element being removable from and replaceable in operative engagement with said trip device without disturbing the seal of the latter, and means actuated by said actuating means for said AContact members for rendering said auxiliary current-responsive trip actuating. element inoperative when said contact members are in the open position.

17. The combination with a trip device for a multi-pole circuit breaker, said trip device being removable from said breaker as a unit and including a trip bar which is movable for causing the automatic operation of the circuit breaker contacts to the open position and a calibrated current-responsive element for each pole adapted to actuate said trip bar upon the occurrence of predetermined conditions of one-or more auxiliary current-responsive elements operable upon the occurrenceof other predetermined conditions to actuate said trip bar, said auxiliary current-responsive elements being removable from and replaceable in operative relation with saidtrip device without disturbing the calibration of said first-named current-responsive elements.

18. The combination with a trip device for a multi-pole circuit breaker, said trip device being removable from saidv breaker as a unit and including a trip bar normally biased to a latching position for retaining the circuit breaker contact operating mechanism in the closed position and a calibrated movable current-responsive element for each pole, said trip bar having a projection for each pole adapted for operative engagement with a current-responsive element for movement thereby to the tripped position upon the occurrence of predetermined conditions oi' one or more auxiliary current-responsive elements operable upon the occurrence `-of other predetermined conditions, said auxiliary current- 1 responsive elements having means operatively engaging at least one of said projections to actuate said trip bar to the tripped position independently of said calibrated current responsive elements, said auxiliary current-responsive elements beu ing releasable from and replaceable in operative relation with said trip device without disturbing the calibration of said first-named current-responsive elements. l 19. In a circuit interrupter, actuating means m for opening and closing the circuit interrupter, an under-voltage trip device operable to cause said actuating means to open the circuit interrupter upon the occurrence of a predetermined under-voltage condition, said trip device includu ing a member biased to move to tripped position and current-responsive means normally holding said memberv and releasing it upon the occurrence of said predetermined under-voltage condition, and connecting means including a' resilient member positioned between said actuating means and said biased member and through which movement of said actuating means is transmitted to said biased member for returning it to position where it is heid by the current-responsive means, said resilient member permitting greater movement of said actuating means than is required to return said biased member into operative relation with said holding means.

20. In a circuit interrupter, a base member, o separable contact means for opening and closing the circuit through the circuit interrupter positioned on the base member adjacent one end thereof, actuating means for the contact means positioned directly against the base member ada jacent the mid-portion thereof, a trip unit including current-responsive means positioned on the base member adjacent the other end thereof,v

an auxiliary trip devic'e'positioned in the space beside said actuating means and between said o trip unit and said contact means, connecting means extending from said auxiliary trip device to said trip unit for actuating the trip unit upon operation of the auxiliary trip device, and means movable upon the operation of said actuating u means to act on said auxiliary trip device.

21. In a circuit interrupter, a base member, separable contact means for opening and closing the circuit through the circuit interrupter positioned on the base member adjacent one end y thereof, actuating means for the contact means positioned close to the base member adjacent the mid-portion thereof, a trip unit including current-responsive means positioned on the base member adjacent the other end thereof, an under-voltage trip device positioned in the space beside said actuating means and between Said trip unit and said contact means, said undervoltage trip device including a coil and an armature biased to move to tripped position, an oper- 7 ating connection extending from said under-voltage trip device to said trip unit for actuating the trip unit upon movement of the armature to tripped position, and means movable upon the operation of said actuating means for engaging and resetting theundervoltage trip device after each movement oi the armature to tripped position.

22. In a circuit interrupter, a base member, separable contact means for opening and closing the circuit through the circuit interrupter positioned on the base member adjacent one end thereof, actuating means for the contact means positioned close to the base member adjacent the mid-portion' thereof; a trip unit including current-responsive means positioned on the base member adjacent the other end thereof, a shunt trip device including a coil, an armature movable by the coil and a cut-oil' switch in series with the coil, all positioned in the space beside said actuating means and between said trip unit and said' contact means, an operating connection extending from said shunt trip device to said trip unit for actuating the trip unit upon movement of said armature, and means movable upon the operationof said actuating means for operating said cut-oli switch after each operation ot the shunt trip device.

23. In a circuit interrupter, separable contact means, actuating means for causing said contact means to open and close the circuit, a trip unit including electro-responsive means operable to cause said actuating means to open the circuit. a housing enclosing said trip unit, an auxiliary trip device including a second electro-responsive means mountedoutside of said housing, an opening in said housing, connecting means extending from said auxiliary trip device through said opening to actuate7 said trip unit by said second electro-responsive means, and said auxiliary trip device with said connecting means being removable from' and replaceable in operative relation with said trip unit through said opening without opening said housing.

24. In a circuit interrupter, separable contact means for opening and closing the circuit, a `mechanism for operating said contact means, a shunt trip device tor causing the actuation of said operating means, said shunt trip device including an electro-magnet and a cut-oil' switch therefor mounted together to form a single unit, said shunt trip device including the electro-magnet and the cut-oil.' switch being removable from and replaceable on the circuit interrupter as a unit, and means movable with said operating mechanism for actuating said cut-oil switch when said operating mechanism has been caused to operate by the shunt trip device.

.- 25. In a removable shunt trip unit for a circuit breaker, an electro-magnetic device includ- A ing a coil, an amature movable by the coil, and a'spring opposing said movement of the armature by the cou, a cut-on switch mounted on, said electro-magnetic device to i'orm. a unitary structure therewith and including contacts connected in series with said coil, circuit brekerv operating means extending from the armature for engaging and operating the circuit breaker, and-an operating member for the cut-oi! switch engageable andmovable by the circuit breaker.

26. In an under-voltage trip unit for a circuit breaker, a solenoid having an opening therethrough, an armature movable in said opening but normally held by the solenoid, biasing means for moving said armature when released by the solenoid, circuit breaker operating means extending from one end of said opening for engaging and operating the circuit breaker upon movement of the armature, and resetting means for returning said armature against said biasing means into position where it may be held by said of the armature, and resetting means for returning said 'armature against said'biasing means intoposition where it may be held by said solenoid, said resetting means having a portion extending from the other end of said opening and being engageable and movable by the circuit breaker, and said resetting means including a member movable by the circuit breaker and a resilient connection between said member andv the armature permitting said member to be moved by the circuit breaker a distance greater than the armature may be moved.

28. In a multi-pole circuit interrupter, a base member, a line terminal member for each of the poles of the circuit interrupter, said line terminal members being positioned at intervals across one end of said base, a second line terminal member for each of the poles of the circuit interrupter, said second line terminal members being positioned at intervals across the other end of said base, a plurality of separable contacts positioned at intervals across said base adjacent the line terminal members at one end of the base, a main trip device including current responsive tripping means for a plurality of said poles positioned at intervals across said base adjacent the line terminal members at the other end of said base, an actuating mechanism for said separable contacts positioned on said base intermediate said plurality of contacts and said main trip device, said actuating mechanism being of less width than the width of said main trip device and of less width than the width of said plurality of contacts, an auxiliary trip device positioned in the space beside said actuating mechanism and intermediate said plurality of contacts and said main trip device, and connecting means extending from said auxiliary trip device to said main trip device for actuating said main trip device upon operation of the auxiliary trip device.

29. In a multi-pole circuit interrupter, a base member, a line terminal member for each of the poles of the circuit interrupter, said line terminal members being positionedat intervals across one end of said base, a second line terminal member for each of the poles of the circuit interrupter, said second line terminal members being positioned at intervals across the other end of said base, a plurality of separable contacts positioned atl intervals across said base adjacent the line terminal members at one end oi' the base, a

ture main trip device including current responsive tripping means for a plurality of said poles positioned at intervals across said base adjacent the line terminal members at the other end of said base, an actuating mechanism for said separable contacts positioned on said base intermediate said plurality of contacts and said main trip device, said actuating mechanism being of less width than the Width of said main trip device and of less width than the width of'said plurality of contacts. and under-voltage trip device positioned in the space beside said actuating mechanism and between said plurality of contacts and said main trip device, said under-voltage trip device including a coil and an armature biased to move to tripped position, an operating connection extending from said under-voltage trip device to said main trip device for actuating said main trip device upon movement of said armature to tripped position, and means movable upon operation of said actuating mechanism for resetting the under-voltage trip device after each movement of the armature to tripped position.

30. In a multi-pole circuit interrupter, a base member, a line terminal member for each .of the poles of the circuit interrupter, said line terminal members being positioned at intervals across one end of said base, a second line terminal member for each of the poles of the circuit interrupter, said second line terminal members being positioned at intervals across the other end of said base, a plurality oi' separable contacts positioned atl intervals across said base adjacent the line terminal members at one end of the base, a main trip device including current responsive tripping means for a plurality of said ,poles positioned at intervals across said base adjacent the line terminal members at the other end of said base, an actuating mechanism for said separable contacts positioned on said base intermediate said plurality of contacts and said main trip device, said actuating mechanism being of less width than the width of said main trip device and of less width than the width oi' said plurality of contacts, a shunt trip device including a coil and an armature movable thereby positioned in the space beside said actuating mechanism and between said plurality of contacts and said main trip device, an operating connection extending from said shunt trip device to said main trip device for actuating said main trip device upon movement of said armato tripped position, a cut-off switch connected in series with said coil and positioned in the space beside said actuating mechanism and between said plurality of contacts and said main trip device, and means movable upon the operation oi said actuating mechanism for operating said cut-oir switch after each operation of the shunt trip device.

JEROME M. SANDIN.