US2451962A

US2451962A - Circuit breaker

Info

Publication number: US2451962A
Application number: US622048A
Authority: US
Inventors: Lindstrom Ture; Albert H Baylis
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1945-10-12
Filing date: 1945-10-12
Publication date: 1948-10-19
Anticipated expiration: 1965-10-19

Description

Oct. 19, 1948. T. LlNDsTRoM ETAL CIRCUIT BREAKER Filed Oct. l2, 1945 d. sa. 5, mma; m. EGB R vw. o ma# n A 9 win# .le ,m 9 MW 5T a i M7 ,Il .ne

CIRCUIT BREAKER Ture Lindstrom, Edgewood, Pa., and Albert H.

Baylis, Ypsilanti, Mich., assignors to Westinghouse.Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application October 12, 1945, Serial No. 622,048

(Cl. 20o-108) 26- Claims. 1

This invention relates to circuit breakers and more particularly, to circuit breakers of the type that are tripped instantaneously on overload currents above a predetermined value and after a time delay on lesser overloads.

An object of the invention is to provide a circuit breaker having an improved trip device which is of simple construction, reliable in operation and inexpensive to manufacture. f

Another object of the invention is to provide a circuit breaker with an improved electromagnetic trip device having a magnetic piston sealed in a casing containing a body of uid which is moved relative to the piston by an armature disposed externally of said casing while the magnetic piston is restrained against movement by the magnetic forces to provide time delay tripping of the breaker. v

Another object of the invention is to provide a rcuit breaker with an improved electroresponsive trip device comprising a sealed casing containing a body of fluid, the casing being moved by an armature to trip the breaker and having a magnetic piston disposed within the casing to delay movement of the casing. Y

Another object of the invention is to' provide a circuit breaker with an improved electromagnetic trip device wherein the tripping armature is normally latched and is released to trip the breaker after a time delay by the movement of a sealed casing relative to a magnetic piston which is disposed within the casing and held substantially stationary by the magnetic forces during tripping movement of the casing.

Another object of the invention is to provide a circuit breaker according to the preceding paragraphs wherein sealed casings having different.'

lar inthe appended claims. The invention itself,

however, both as to structure and operation, together with additional objects and advantages thereof, will be best understood from the follow- 2 ing detailed description of one embodiment thereof when read in conjunction with the accompanying drawing, in which:

Figure 1 is a side elevational view, partly in section, ci a. circuit breaker embodying the invention,

Fig. 2 yis a front elevational view of the trip device with the cover plate removed,

Fig. 3 is a front elevational view of the trip device showing the cover plate, and

Fig. 4 is an enlarged sectional view oi.' the movable core structure.

Referring to Figure 1 of the drawings, the reference numeral il designates a base of strong insulating material which supports the various parts of the circuit breaker. A pair of terminals I3 and I5 are suitably secured to the base andy each terminal hasone or more connecting studs i9 which extend through the back ofthe base and serve to electrically connect the'breaker to the circuit which it controls.

The upper terminal I3 has a contact block 2| of rigid conducting material secured thereto; and a rigid contact block 23 secured to the base is electrically connected to the lower terminal i5 through the energizing winding of the trip device of the breaker, which will be hereinafter described.

'Ihe contact means and mechanism of the circuit breaker illustrated are similar to the circuit breaker fully disclosed in Patent No. 2,214,471, is-

sued September 10, 1940 to Leon R. Ludwig and Merle E. Horn, and assigned to the assignee of the present invention. Hence only a brief description of these parts will be given in this application.

The main

stationary contacts

25 and 21 are rigidly secured to the contact blocks 2| and 23, respectively; and the auxiliary stationary contacts29 and 3| are secured to a triangularlyshaped contact platform 33 of conducting material which is mounted on the upper portion of the block 2| for limited tilting and rocking movement by means of pins 35 projecting from the opposite sides of the platform which engage in slots 31 provided in a pair of side Walls 39 secured to the block 2|. The platform 33 is biased outwardly from the base by a plurality of springs 4| and 43, and outward movement of the platform is limited by the engagement of the pins 35 with the outer ends of the slots 31 and by stop projections 45 carried by the platform adjacent its upper end. The platform 33, and consequently, the auxiliary contacts 29 and 3| are electrically connected to the terminal I3 by means of a flexible shunt conductor 41.

ries a main contact,bridging member 55 lfor bridging the

main contacts

25 and 21, and an auxiliary contact member 51 for engaging the stationary auxiliary contacts29 and 3|, the auxillary contact membes 51 beings'ecured to the upper end ci the channel-shaped contact arm 49 by a.

plurality of screws 59. Y I

' The main contact bridging member 55 is formed of rigid conducting material, and is loosely A mounted on, the contact arm 49 for limited movement relative to the contact arm toward and away from the main contacts 25 and21,by A

means of a pair of studs' 8| secured to the contact carrying arm 49, only one stud being shown? A pair oi.' coil springs (not shown) encircle the studs 6|, and are disposed between the contact carrying arm 49 and the bridging member 55 for biasing the bridging member toward, the

stationary

main contacts

25 and 21 with a predetermined force. The -ends of the bridging member 55 are beveled to-lie parallel with the beveled edges of the contact blocks 2 Land 23, and have a'pair of contacts 81 secured thereto for engaging the main

stationary contacts

25 and 21.

The auxiliary contact member 51 is fofmed of f rigid conducting material, and has an intermediate contact $9 and an arcing contact` 1| secured thereto for engaging the intermediate and arcing contacts 29 and 3| of the stationary contact means.

A exible shunt conductor 1.3 electrically con-l nects the auxiliary contact arm 49 to the main stationary contact block 23. The exible conductor 13 has its upper end secured to the contact arm 49 by the lower screws 53. The lower end of the exible shunt conductor 13 is secured to the lower contact block 23 by means of 'a bolt y11.4

IThe switch member 5 I 'has a yoke-shaped lower end which is pivotally mounted between the sidewalls of a main frame 19 by means of the pivot pin 8|. The switch member 5| is movable about its pivot axis to open and closed circuit positions to open and close the contact means of the breaker by means of 'an operating mechanism indicated generally at 88. f y

The operating mechanism 83 is supported by tl'ie-main frame '19 and comprises an actuating lever'95 pivoted on a pin 81' carried by the frame,

, and isconnected to the switch member| 5| by a link 99. An operating member 9| is also pivoteci on the pin 81 for movement about the same axis as'the actuating lever 85. The actuating lever -85 is normally and releasably connected to the operati member 9| for movement thereby by Ameans .of a pair of latches 93 and 95, which are v vpivotally mounted on the lever 85 at 91 and 99,

The latch 93 engagesa roller |0| respectively. A carried by the operating member 9|, and this latch is, inL turn, held in latching position by the auxiliary latch 95. Theoperating member 9| is adapted` to be releasably held in closed 'cir--l cuit position by means of a main holding latch |03 pivoted at ||9, which releasably. engages the roller- |I. with a curved tailpiece by means or which it is `released to cause release oi' the latcl 93 and consequent tripping of the circuit, breaker by the release oi the actuating lever 85 from its connection with the operating member 9|. When The auxiliary latch 95 is providedA l released the actuating member 95 moves in a counterclockwise direction about the pivot axis 81, causing` opening of the movable contact means.

member 9|. 'I'he switchv member 5| and the Iactuating lever 35 are biased to open position by means of a pair of accelerating springs |99 (only one being shown), which are connected at their upper ends to the switch member 5| and at their lower ends to the sides of the'main frame 1-9.

To close the circuit breaker after it has been tripped open, the operating member 9| is iirst moved in a counterclockwisedirection about the pivot axis 81 to the open position to eiect resetting of the latches `and reestabishment ofV the releasable rigid connection between the actuating lever 35 and the operatingmember 9|. After the rigid connection is thus established, the operating member 9| is moved in a clockwise direction to-closed position by means of a handle III to eiect closing of the contact means of the breaker. The clockwise or closing movement 4of the operating member 9i is limited by a portion 92 thereof striking a iixed stop 94 on the frame 19. When the parts have been moved to closed position, the main holding latch |93 reengages the roller ||l| to hold the operating member in closed position.v The stop 94 is located to permit a slight overtravel of the member 9 Iv to insure proper engagement, of the latch |93 with the roller IUI. It will be noted that the construction oi -the operating mechanism is such that the movable contactlmeans is trip-free of the operating member 9|; that is, when the breaker Iis tripped, the contact means move to open position irrespective'of the position oi the operating member 9|.

The mounting arrangement of the contact means is such that during opening of the breaker the main'lbridging`member`55 is iirst separated y from the

stationary contacts

25 and 21, while the auxiliary contacts remain in engagement by reason of thehoutward movement of the contact platform -33 under the inuencefof the biasing springs 4| and`43. .After the bridging member has separated a predetermined distance from the main stationary contacts, the intermediate contacts 2 9 and 99 begin to separate. This takes place as soon as the pins 35 engage the ends of the slots 31. During this time, thearclng conf, tacts 3| and 1i remain in engagement -due to the rocking movement of the contact platform 38. After the intermediate contacts have separated a predetermined distance, the arcing contacts 3i and 1| begin to separate. During closing. the lcontacts engage in the reverse order, as will readily be understood. It will thus be-seen that the arc formed during separation of the contacts is drawn onlybetween the arcing contacts 3| j and 1|.- The circuit breaker is adapted to be tripped open either manually, or automatically, in re- `sponse to predetermined overload conditions in the circuit, by means of a trip device indicated Y i5 ldetermined 'overload conditions to move the trip acentos l lever |11 to tripping position to cause automatic openin of the circuit breaker.

One m |23 of the trip lever ||1 is odset and extends inwardly toward the base of the circuit breaker, and has its inner end disposed immediately above the trip means |2 to be engaged and moved by a plunger of the electromagnet to effect automatic tripping of the breaker. The

arm |23 of the trip lever is provided with a pro` position and the trip lever to its normal inoperal tive position, as shown in Fig. 1.

The movable core structure comprisesa sealed casing |43 of a non-magnetic material containing a body oi' oil or other liquid o! suitable viscosity. The casing |43fis disposed for vertical movement in the 'winding |31 and has its upper` end operatively connected to the movable armature |39 by' means of a lever |45. The lever |45 comprises a pair of spaced parallel levers connected by a yokek |41 and pivoted on ,a pin |49 supported in the spaced, upwardly extending 7 arms of a bracket |5|4 which is secured to the upper ilxed core member |3i. pivotally connected to the upper end of the casing |43 by means of a pin |53 which extends Ythrough openings in projections on the upper end of the casing. The opposite endci the lever |45 is connected to the movable armature |39 by means of pins |55 which extend through openings in the arms of the lever |45 and through corresponding 1openings in projections |51 lextending upwardly. from each side of Ithe movable armature |39. Thus, when the movable armature |39 moves downward, the sealed casing i43,

due to the lever |45, will move upward.

A spring |39 tensioned between the pin |53 ci the lever |45 and a bracket i9| suitably secured to the upper fixed core member |31 normally biases the movable core, structure i4! and the movable armature 139 toward a central position. With normal current flowing in the energizing coil the weight of the movable core structure is sufcient to cause 'the parts to assume the positions in which they appear in Figure 1.

When an overload current below ay predetermined value of, for instance, 1000% of normal rated current occurs the magnetic forces attract the movable armature |39 and the tripping armature l'33'iioward each other. Since the tripping armature |33 is latched in its retracted position it cannot move, but the movable, armature |39 starts to move downward and, through the agency of the pivoted lever |45 draws the sealed casing |43 upwardly and eventually the projection |19 on the bottom member 19| of the casing |43 engages the arm |11 of the bell crank |69 and operates the bell I crank and the latch arm |31 to release the tripping armature |33. The' tripping armature |33 immediately moves upwardly carrying the trip' rod |35 therewith to engage the trip lever ||1 and trip the breaker in the manner previously described.

lWhen an overload below the afore-rnentioned predetermined magnitude occurs, such, for instance, as is occasioned by the turning on of lights, it is desirable to interpose a time delay between the occurrence of the overload and the tripping of the breaker, so that, should the circuit condition return to normal before tripping is effected, the trip device may return to normal condition without having tripped the breaker.

The movable armature |35 Vand the tripping armature |33 are guided in their 'vertical reciprocal movement by means of a guide bracket |59 of nonmagnetic/material having formed over portions '|51 (IllgfZl/secured by means of rivets |53 to bottom and top sides` respectively of the upper and lower fixed core members |31. Channel-shaped guides |55 are formed outwardly :from the bracket |55 one embracing each side of the armature |39 and the tripping armature |33, to guide said armatures in their vertical movements.

Y The tripping armature |33 is normally latched in i-ts unattracted position by means of a latch member |51 which forms one arm of a bell crank lever |55 pivoted on a pin |1| supported between the downwardly extending portions |13 ci a bracket |15 (see Figs. 2 and 3) secured to the In the present invention time delay is effected by a piston |93 of magnetic material disposed in the sealed, casing |43 and normally biased by means of a compression spring |95 to the upper end of the casing. The spring |95 is compressed between a flange |91 of magnetic material integral with a core member |99 also of magnetic material in the bottom of the casing and thc bottom of the piston |93 inside a cylindrical extension 20| of the piston. The piston |93 is spaced from the top of the casing |43 by means' of a stop 203 secured to and projecting inwardly from the top of the casing. The piston |93 is provided with two oil passages 205 and 281 extending longitudinally therethrough. The passage 201 is for the purpose oi relieving the oil pressure from above the piston to permit its restoration following an operation and to -this end is provided with a ball check valve 2119r vclisposed in the enlarged lower end 2|| of the passage and loosely retained therein by means of a pin 213. When the casing |43 is moved upwardly past the piston |93 during the occurrence of an overloadvl the oil pressure presses "the ball` 2119 7 against a conical seat thus closing the passage 201.

A ball valve 2|5 is disposed in the enlarged upper portion 2|8 of the passage 205 and is biased downwardly' against a conical seat by a spring 2|7 compressed between the head 2|9 of a guide rod 22| and a pin 223 inserted in suitable openings inthe piston and extending diametricaily across the enlarged portion 2| 8 of the passage 205. The guide rod 22| is provided with an axial slot at 225 embracing the pin 22,3. The pin 223 may be assembled in any one of a plurality of openings 224 (three being shown) provided therefor in the piston to vary the compression of the spring 2|`| thereby varying the pressure at which the valve 2|5 will open. The purpose of this adjustment will be more fully described later.

The trip device operates with time delays of dlilerent duration in two distinct ranges of over load currents below a predetermined magnitude. and instantaneously in response to an overload above the predetermined magnitude, or a short circuit. These ranges of overload currents may be arbitrarily defined as, for instance, low range up to 200% of normal current, intermediate range between 200%V and 1000% of normal, and instantaneous 1000% or more of normal current. Assuming an overload within the low range of overload currents, the operation of the trip device will now be described.

Upon the occurrence of an overload in the low range, the winding |37 becomes energized and the magnetic forces across the air gap between the armature |39 and the tripping armature |33 attracts these armatures toward each other, but, since the tripping armature is latched and cannot immediately move, the armature |39 is drawn downwardly. The downward movement of the armature |39 acting through the lever |95 (Fig. l) and aided by the spring |89 starts to move the sealed casing |43 upwardly. The piston |93 is so disposed in the magnetic field that the magnetic forces hold it substantially stationary while the casing |23 is drawn upwardly past it by the armature |39. As the casing |23 starts to move upwardly,lthe pressure of the oil below the piston closes the check valve 209 (Fig. 4) compelling the oil to fiow through the passage ,205 or between the piston and the wall of the casing. The spring 2|7 holds the valve 2 l5 closed on overloads up tov 200% of normal or in the low range of overloads, consequently, the oil ows, around the piston in this range of overloads, thus providing a relatively long time delay.

Continued movement of the armature `|28 reduces the air gap between the armatures |92 and |33 and 'increases the forces acting thereon. This is counteracted to a certain extent after the spring |89 (Fig. 1) passes above center where it opposes upward movement of the sealed casing. Eventually, after at time interval which. varies inversely with the magnitude of the overload, the projection |79 (Fig. 1) on the bottom of the casing engages the arm |77 and operates the bell crank |69 to release the tripping amature which then moves upwardly to trip the breaker in the previously described manner. Additional magnetic pull is provided to unlatch the armature |33 ,by the core member |99. As the casing |63 moves upwardly the core |99 reduces the air gap between itself and the magnetic piston |93 thus increasing the upward pull on the casing.

When the breaker is tripped open the circuit is interrupted and the winding |31 of the trip device becomes deenergized. At this time, the

v tripping means. pression spring 229 compressed between a bracket 23| (Figs. 2 and 3) mounted on the right hand spring |89 exerts a force on the lever |45 biasing the lever in a counterclockwise direction. This force raises the armature |39 and lowers the movable core structure |4| until the spring |89 and the lever |45 are in line. Thereafter the weight of the core structure |.4| restores the casing |43 and the armature |39 to the normal unattracted position. During the restoring movement the entire movable core structure moves downwardly as a unit, and, at the same time, the spring |95 forces the piston |93 upwardly against the stop 203 (Fig. 4). The-pressure of the oil above the piston, during the restoring action, opens the check valve 209 permitting free flow of oil through the passage 207 to the other side of the piston 'thus providing for quick resetting of the piston. When the trip device is deenergized upon opening of the breakenthe tripping armature |33 drops immediately to its unattracted position where it is relatched by the latch |67 under the inuence of the spring |83.

The operation of the trip device upon the occurrence of an overload current in the intermediate range, that is, between 200% and 1000% of normal current, is the same as the operation just described withl thevdiierence that the pressure oi the oil in the casing |43 below the piston is greater due to the greater energization of the electromagnet. When the winding |37 is energized in response to an overload of approximately 200% of normal current or more, the pressure is suicient to compress the spring 2 7 and open the valve 2|5 thus providing for a greater flow of oil to the other side of the piston |93 which results in a shorter time delay in the intermediate range of overloads than in the low range where the valve 2|5 does not open.

The breaker is tripped open instantaneously in response to overload currents above the aforementioned predetermined value, or in response to short circuits by means of a small instantaneous trip armature comprising an iron screw 227 screwed into the lower end of the non-magnetic trip rod |35 and seated in the opening in the trip armature |33. Upon the occurrence of an overload current above the predetermined value or a short circuit, the armature 227 is attracted upwardly to bridge the air gap between armatures |33 and |39 and actuates the trip rod |35 to instantaneously trip the breaker independently of the time-delay mechanism and independently of the armature |33 and |39. When the circuit is interrupted and the trip device deenergized, the trip rod and the armature 227 return to their unattracted positions by their own-weight. The trip armature |33 remains latched and is not operated on instantaneous tripping operations.

The minimum overload current `required. to instantaneously trip the breaker may be varied by varying the size or mass of the screw 227 cornprising the instantaneous trip armature.

Means is lprovided to calibrate the time delay This means comprises a compin |55 which connects the lever |35 to the armature |39, and a block 233 threadedly engaging a rotatable rod 235. The rod 235 is disposed vertically and the reducedl upper end thereof engages a suitable opening in the bracket 23|. The lower threaded portion of the rod 235 is rotatably supported on the lower fixed core member |3| by means of a collar 237 secured to the rod and resting on the core member |3|. The lower end of the rod 235 belowthe core member IBI is provided with a knurled knob 239 which is secured thereto for rotating the rod.

Rotation of the rod 235 moves the block 233 up or down depending on the direction of rotation and varies the compression of the spring 229 which opposes operation of the armature 139 thus varying the overload current required to effect tripping of the breaker. The block 233 is prevented from turning with the rod 235 bya projection 24i lthereon extendingl through an elongated slot 243 extending vertically in a scale plate 245. The scale plate 245 is suitably secured to the front of the trip device and bears a scale indicating the percent of overload current required to trip the breaker. Y y

There is also provided means -for changing the low and intermediate ranges of overload currents required to trip the breaker; viously setV forth that With the pin I223 mounted in the upper one of the holes 224, the low and intermediate ranges o! overload currents were respectively 100% to 200% of normal and 200% to 1000% of normal current. If the

2,23 is assembled in the intermediate hole 224, the spring 2H will be given a greater compression and will require a greater pressure and consequently a higher current value to open the valve 2 I5. The low range of overloads with the pin 223 in the intermediate hole 224 may then be 100% to 300% of normal current and the intermediate range may be from .300% to 1000% of normal current value. 223 in the lower one of the holes 224 may-establish the low range of overload currents at from 100% to 400% of normal and the intermediate range from 400% to 1000% of normal current values. The limits of the low and intermediate ranges of overloads set forth ,are to be considered merely by way of example and these may bevaried considerably. to suit particular requirements. For instance, by the provision ofa stronger or weaker spring 2I1 entirely diierent sets of values may be established.

The movable core structure |4I including the casing i43 is readily removable from the trip device by removing the pin |53 and dropping the casing assemblage out of the magnet. other casing assemblage having different operating characteristics may then be inserted. YFor instance, three dierent casing assemblages may be provided and interchangeably installed in theV breaker, each. of the casing assemblages having the pin 223 inserted in a diierent hole'2-24 and/or having diilerent strength springs 2I'I assembled therein. Each of the c asings may be marked with identication corresponding to one of the three time-current curves marked von the scale plate 245 (Fig. 3). e

By latching the tripping armature agains movement and then releasing it after the magnetic airgap is substantially reduced the maximum magnetic pull is utilized to trip the breaker. When released, the tripping armature |33 is actuated to trip the breaker unopposed by the Calibrating spring 229.

Having described the invention in accordance with the patent statutes, it is to be understood that various changes and mociications4 may be made in the structural details and combination of elements disclosed without Adeparting from some of the essential features of the invention. It is therefore, desired that the language of the appended claims be given as reasonably broad interpretation as the prior art permits.

It was pre- In the same manner assembling the pin- We claim as our invention:

movable contacts and operating mechanism therefor, the combination of a trip member operable to eiect automatic operation of said operatingmechanism, an electromagnetic trip device comprising an energizing winding, a rst armature operable to effect operation of vsaid trip member, means comprising a sealed casing movable to cause tripping operation of said ilrst armature, a second armature for moving said casing, and means disposed in said casing and responsive to energization of said electromagnet to delay tripping movement of said iirst armature.

2. Ina circuit breaker comprising relatively movable contacts and operating mechanism therefor, the combination of a trip member operable to effect automatic operation of said operating mechanism, anelectromagnetic trip device comprising an energizing Winding, a first armature operable to effect operation of said trip member, means vcomprising a sealed casing disposed in said winding and movable to'cause tripping operation of said first armature, a second armature disposed outside of said winding-for operating said casing, and means disposed in said casing and responsive to energization of said electromagnet to delay tripping operation of said iirst armature.

3. In a circuit breaker comprising relatively movable contact and operating mechanism therefor, the combination of a trip member operable to effect automatic operation of said operating mechanism, an electromagnetic trip device for operating said trip member comprising an ener- Igizing winding, a tripping armature operable to cause operation of said trip member, a nonmagnetic casing movable to effect operation of said tripping armature, a second armature movable relative to said casing by said electromagnetto move said casing, and a magnetic member disposed in said casing /and responsive to energization of-said winding to oppose movement of said tube.

In a circuit breaker comprising relatively movable contacts kand operating `mechanism therefor, the combination of a trip member operable to eiiect an operation of said operating mechanism, a trip device for operating said trip member comprising an energizing winding, a rst armature movable to trip the breaker, means releasably restraining said first armature against tripping` movement, a casing movable to operate said restraining means to release said first armature, a second armature operatively related to said casing and operable upon.energizat1on of said windingto move said casing, and means disposed in said casing responsive to energization of said windingv to retard movement of said casing.

5. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, the combination o'f a trip member operable to effect automatic operation of said operating mechanism, an electromagnetic trip device for operating said trip member comprising an energizing winding, a, tripping armature, means releasably restraining said tripping armature against movement, means comprising a sealed casing movable to operate said restraining means to permit operation of said tripping armature, a movable `armature for moving said sealed casing, and means comprising a piston of magnetic material disposed in said casing for' delaying movement oi said casing. I l 6. 'In a circuit breaker comprising relatively movable contacts and operating mechanism thereto the combination of a trip member operable to eiiect operation oi said operating mecha-g nism, an" electromagnetic trip devicel iorperating said trip member comprising a fiixed, magnetizable structure, an energizing winding, a releasable member operated by, said electromagnet and operable when released to operate said trip member, a casing movable to efiect release of `said releasable member, an amature operable upon energization of saidj `winding to move said casing to eiiect release of said releasable member, V and a magnetizable member in said casing responsive to energization of said winding toretard movement of' said casing.

'7. In acircuit breaker comprising relatively movable contacts and operating mechanism therefor, the combination of a trip member operable to effect operation of said operating mechanism, an electromagnetic trip device for operating said trip member comprising a ilxedf magnetizable structure. an energizing winding, a releasable member operated by said electromagnet and\operable. when released to operate said-,trip member, a casing movable to elect release voi said releasable member. an armature operable upon energizationof said winding to move said casing to effect release oi' said releagsable member, Laimagnetizable member -in said casingV responsive to energization of said winding t retardmovement of said casing, and means operable by said electromagnet independently oi said releasable member to operatel said trip member. Y

8. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, the combination of an electromagnetic trip device for causing an automatic operation oi' Ysaid operating mechanism comprising a magnetic circuit, an energizing winding, a releasable magnetizable l member yin the magnetic ,circuit movable when released to eiiect tripping oi the breaker, a sealed element movable to release said releasable member, a second magnetizable member in said magnetic circuit operable in response to' overload currents insaid winding to move said sealed element to release said releasable member,

andtime delay means comprising a magnetizable member sealed in said element and disposed in said magnetic circuit to be restrained against movement in response to overload currents to oppose movement of said element.

9. In a circuitbreaker comprising relatively movable contacts and operating means therefor, the combination of a trip member operable to cause automatic operation oi said operating means, an' electromagnetic trip device for operating saidtrip member comprising .a magnetic circuit, an energizing winding, areleasable' magnetizable member in said magnetic circuit operable 1in response to overload currents below a predetermined value in said winding to operate said trip member, a sealed casing disposed in said winding and movable to release said releasableV member, a first amature in said magnetic circuit operablein response to overload currents below said predetermined value in said winding to move saidcasing, time delay means comprisingv a magnetizable'member sealed insaid casing and disposed in said magnetic circuit to be restrained against movement by energization'oi said windcasing. and a second amature in said magnetic circuit operable independently of said Jreleasable member in response to overload currents above said predetermined value to instantaneously 5 operate said trip member.

10. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, 'the combination of a trip member operable to effect automatic operation of said operating mechanism, an electromagnetic trip device comprising an energizing winding. a'rst armac ture operable to eiect operation of Vsaid trip member, means comprising a sealed casing movable to cause tripping operation of said nrst amature, a second amature for moving'said casing, means disposed in said casing and responsive to energization oi said electromagnet to delay trippingV operation of said first amature, and adjustable means for varying the operating characteristic of said second armature. 1 -f 1l. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, the combination oia trip member operable to enect automatic operation of said oper- '25' atingv mechanism, an electromagnetic trip device comprising an energizing winding, a rst armature operableto efiect operation of 'said tripA member, means comprising a sealed casing mov- I ableto cause tripping operation oi said iirst 36 armature, asecond armature for operating said casing. means 'disposed in said casing and-re- .sponsive' to energization oi said electromagnet to delaytrippingoperation of said rst armature;

resilient-means opposing operation oi said second 33 armature, and means operable to vary the tension 'of said resilient means to vary the operating characteristic of said trip device.

12. In a circuit breaker comprising relatively movable contacts and operating mechanism 4h therefor, the combination of a trip member oparable tdelect automatic operationof said operating mechanism, an electromagnetic tripdevice comprising an energizing winding, a iirst armature operable to edect operation ofsaid trip member, means comprising'a sealed casing movable -to cause tripping operation of said firstarmature, a second armature for operating said casing, spring means biasing said-casing against tripping movement during the iinal part of the tripping movement and tohus Vopposing tripping op,-4

eration of said casing. and means disposed in said casing and responsive to energization of said electromagnet to delay tripping operation o'f said iirst ing mechanism, an elcctromagnetic'tripl device 6o' comprising an energizing winding. a rst arma- A ture operable to effect operation of sad trip member,-rneans comprising a sealed casing movable to cause tripping operation ofl said n rst armature, a

second amature for moving said casing, a spring associated with said casing to rst bias said casing in tripping direction and then to opposestrlpv ping movement of said casing, and means disped in said casingand responsive to energization of said electromagnet to delay'tripping operation of 7o saldrst amature. le. linV a circuit breaker comprising relatively movable contact A and operating mechanism therefor, the combination of a tri-p member oping in response to overload currents below said erable to edect automatic operation of said oppredetermined value to retard movement oi said erating mec an electromagnetic trip deyture against movement, a non-magnetic casing 13` vice for operating said trip member comprising an energizing winding; a tripping armature operable to cause operation of said trip member, latch means normally restraining said .tripping armamova'ble` to operate said latch means to release said tripping armature, a secondarmature movable relative to said casing by .said electromagnet to move said casing, and a magnetic member dis- -posed in said casing and responsive to energization ofsaid winding tooppose movement of said casing.

`l5. In a circuit breaker comprising relatively l movable contacts and operating `mechanism therefor, the combination of a trip member opermined value to move said chamber, time delay means comprising a magnetic member disposed in said chamber to be restrained against movement in response to overload currents below said predetermined value to retard tripping operation ofv said chamber, means operable by said rst armature to actuate said .trip member, and a third armature on said means operable in response to overload currents above said predetermined value to operate said means independently offsaid rst 4armature and said `second armature to instantaneously operate the trip member. f

16. In a circuit breaker comprising relatively movable contacts and operating means therefor, the combination cfa trip member operable to effect automatic` operation of said breaker, an electromagnetic trip device for operating said trip member comprising an energizing winding, a first farmature operable to effect operation of said trip member, an element operable by said nrst armature to operate said .trip member, means comprising a sealed chamber movable to eiect tripping operation of said first armature, a second armature operable by said trip device in response to overload 4currents below a predetermined value to move said chamber, .time delay meanscomprising means disposed in said chamber responsive to energiza'tion of said winding to retard tripping movement of said chamber, and magnetic meansfI on said element operable in response to overload currents above said predetermined value to operate said element independently of said iirst armature to instantaneously operate said trip mem- 17. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, the combination of a trip device operable to effect automatic operation of said breaker, said trip device comprising an energizing winding,` a Areleasable armature operable to trip said breaker, means comprising a sealed casing containing a body of uid, said casing being disposed within said Winding and movable upon energization thereof to effect release of said releasable armature, time delay means comprising a magnetizable core disposed within said casing and restrained against movement with said casing by energization of said winding, said core having a passage therein for permitting iluid to flow from one side of said core to the other, valve meansfor con- 75 .trolling the rate of ilow of said uld to thereby control the rate of movement of said casing, and means for adjusting said valve means to vary the rate of flow of said uid to thereby vary the operating characteristic of the trip device.

18. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, the combination of a trip device operable to eiect automatic opening of said breaker, said trip device comprising an energizing winding, a releasable armature operable to .trip the breaker, means comprising a sealed casing containing a `body of iluid,l said casing being movable to effect release o! said releasable armature, a second armature ior moving said casing, time delay means comprising a magnetizable core disposed in said casing and restrained against movement Iby energization of said winding, said core having a passage therein to permit uid to pass from one end of said `casing to the other, valve means for controlling t'he rate oi ilow of said fluid to thereby control -the rate of movement oi' said casing, and means for adjusting .sa-id valve means to van the rate of ilow yof said fiuidto thereby vary the operating characteristics of said trip device.

19. In a circuit breaker comprising relatively l movable contacts and operating means therefor,

the combination of a trip device operable to efvfect automatic operation oi' said breaker, said trip device' comprising an' energizing Wind1ng, an armature operable to effect tripping of said breaker, means comprising a sealed casing containing a body of, iluid, said casing being movable upon energization of seid winding to eiect operation of said armature, time delay means for retardingmovement of said casing comprising a magnetizable core within said casing disposed to be restrained against movement by energization Yo! said winding, said core having a passage therein .permitting fluid to flow from one end of said casing to the other, valve means for controlling ,the rate of flow of said fluid to thereby control the rate'of movement of said casing, and means for adjusting said valve means to vary the rate of flow o! said iluid to thereby vary the operating characteristic of said trip device.

'20. In a circuit breaker comprising relatively movable contacts and operating means therefor, the combination of a trip device operable to effect automatic operation of said breaker, said trip device comprising an energizing winding, an armature operable to effect tripping of said breaker, means comprising a sealed casing containing a body of uid, said casing being movable upon energization of said winding to eiect operation oi' said amature, time delay means for re trding movement of said casing comprising a magnetizable core Within said casing disposed to be restrained against movement by energization of said winding, said core having a passage therein permitting iluid to flow from one end of said casing to the other, valve means for controlling the rate of ilow of said fluid tothereby control the rate o1' movement of said casing, spring means biasing said valve means to oppose ow of uid through said passage, and means for adjusting said spring means to vary the rate oi' flow of said fluid to thereby vary the operating characteristic of said trip device,

21. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, the combination of a trip device operable in response to overload currents' to effect automatic opening operation of said circuit breaker, said trip device comprising an energizing winding, a

i5y movable core member operable upon energization of said winding, a sealed casing containing a body of iiuid movable by said movable core' member to effect tripping of the breaker, time delay means f for retarding tripping movementof said casing comprising a secondary core member\ disposed within said casing to be restrained against movement by energization of said winding, said secondary core member having a passage therein permitting fluid to flow from one end of said casing to the other end and adjustable means associated with said passage to vary the flow of uidto there,-

by vary the rate of tripping movement of said casing.

22. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, the combination of a trip device operable in response to overloadcurrents inthe circuit controlled -by the breaker to effect automatic operation of said operating mechanism, said trip device comprising an energizing Winding, a irst armature operable to effect tripping ofthe breaker, means comprising a sealed casing`movable to cause tripping operation of said first armature, a second armature operable -upon energiza'tion of said windingto move .said casing, time delay means comprising a piston within said casing 4responsive to energization` of said winding to retard tripping movement' of said casing, calibrating means comprising a spring'biasing said second armature against movement. and adjustable means for varying the tensionof said spring to thereby vary the minimum overload current required to move said casing, said iirstv armature when operated moving free of said calibrating spring to trip the'breaker.

23. In a circuitl breaker comprising relatively movable contacts, the combination of an electromagnetic trip device operable to eect automatic opening of said contacts, said trip device comprising an energizing winding, a sealed casing containing a body of 'uid and movable to cause tripping of said breakenan armature operable upon energization of saidwlnding in response to overload currents to move said casingfa second armature disposed in said casing to be held against movement by energization of said winding to re; strict displacement of said uid to thereby retard tripping movement of said casing with a relatively long time delay, land valve means operable to increase the rate of displacement ofvuid to thereby retard tripping movement of said casing with a relatively short'time delay.

24. In a circuit breaker comprising relatively movable contacts, the combination oran electro-- magnetic trip device, operable to effect automatic opening of said contacts, said trip device comprising an energizing winding, a sealed casing containing a. body of uid and movable to cause tripping of said breaker, an armatureoperable upon energization of said winding in response to overload currents to move said casing, a second armature disposed in said basins to lbe held against y movement by energiztion of said winding to restrictv displacement o! said iluid to thereby retard tripping movement o! said casing with a rela- 5 tively long time delay, valve means operable to-k increase the rate of displacement of fluid to thereby retard tripping movement of said casing with a'. relatively short time delay, and tripping means operable at times independently of said casing to l instantaneously trip said breaker. Y

25. In a circuit breaker comprising relatively movable contacts, the combination of an eiectrcmagnetic trip device operable to eilect automatic opening of said contacts. said trip device comprising an energizing winding,'a sealed casing vcontaining a body-oi uid and movable to trip` Y said breaker. a rst armature operable upon energization of said winding in response to over "load currents to move said casing. a time delay 2'0 element having a fluid passage therethrough dis posed in said casing and restrained against movement by energization ot said winding to restrict y the ilow of iiuid t@ thereby. control the .rate oill tripping movement ofsaid casing. in response to'Y overload currents below a predetermined value.

"s andla bypass valve in said passage for controlling the flow of uid to therebyl control therate o tripping movement of said casing in response to overload currents above said predetermined value. 3Q 26. In a circuit breaker comprising relatively movable contactshthe combination of an el'ectromagnetic trip-device operable to eect automatic trippingmovement of said casing in response to' overload currents below a predetermined value,

a bypass valve in s'aid passage for controlling the ow of uid to thereby control the rate of tripping movement of said casing in response to overload f currents above said predetermined value, and a. second armature operable at times independently breaker.

-f LINDSM.

mi* H. BAYLIS.

:mi wilt ENCES @Hm The following references are of record in the file oi' this patent;

Number Name i A 2,072,932 Wilkens M5129, 1937 2,373,998 Elllwin '.a pl. 17, 1945 of said ilrst armature to instantaneously trip said