US2663775A

US2663775A - Circuit breaker

Info

Publication number: US2663775A
Application number: US175374A
Authority: US
Inventors: John B Macneill; William H Stuellein; Merl E Horn
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1950-07-22
Filing date: 1950-07-22
Publication date: 1953-12-22
Anticipated expiration: 1970-12-22

Description

`CIRCUIT BREAKER 5 Sheets-Sheet l Filed July 22, 1950 a www.. Huur Dec. 22, 1953 B. MacNmLL ETAL 2,653,775

CIRCUIT BREAKER Filed July 22, 1950 5 Sheets-Sheet 2 M John B. MucNeilI ,WiIIam H. Siu in ond Meri E. Horn.

ATTO EY Dec. 22, 1953 J. B. MaONElLI. ETAL 2,663,775

` CIRCUIT BREAKER Filed July 22, 195o 5 sheets-sheet :s

505 Fig. 3 255 259 305 Q F lg. 5. 28'

F lg. 4 WITNESSES: INVENTORS John B. MocNeill ,William H. S'ruelleln. m and Meri E. Horn. Y

Dec. 22, 1953 Filed July 22, 1950 WITNESSES:

MMM. 7m

J. B. MacNElLL ETAL 2,663,775

CIRCUIT BREAKER 5 Sheets-Sheet 4 INVENTORS John B. MacNeilI,Wi||iom H. Stuellein und Merl E. Horn.

J. B. MaCNElLL ETAL CIRCUIT BREAKER Dec. 22, 1953 Filed July 22, 1950 WITNEssEs: Percent of C0" Rming lNvENToRs Fig. John B. MucNeill ,William H.Stuel|en und Merl E. Horn. Le# 5f! ATTORN Patented Dec. 22, 1953 CIRCUIT BREAKER John B. MacNeill, Pittsburgh, William H. Stuellein, East McKeesport, and Merl E. Horn, Wilkinsburg,

Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application July 22, 1950, Serial No. 175,374 14 Claims. (Cl. 200108) This invention relates to circuit breakers and more particularly to circuit breakers of the type used for controlling light to moderate power distribution circuits.

An object of the invention is to provide a circuit breaker embodying a novel trip device that is operable to trip the breaker after a relatively long time delay in response to overload currents of relative low value, after a rela- .tively short time delay in response to overload currents of intermediate value below a predetermined value, an instantaneously in response to overload currents above said predetermined value or short circuits.

Another object of the invention is to provide a circuit breaker embodying an electromagnetic trip device having a novel time-delay device and means for limiting the force applied by the electromagnet to the time-delay device.

Another object of the invention is to provide o. circuit breaker having a trip device embodying a novel time-delay device of the liquid dashpot type in which time delays of diierent duration in different ranges of overload currents are provided by admitting liquid to the dashpot at different rates.

Another object of the invention is to provide a circuit breaker embodying a novel time-delay device of the liquid dashpot type wherein different amounts of time. delay are provided by the operation of one or more valves to admit liquid to the dashpot at diierent rates.

Another object of the invention is to provide a circuit breaker embodying a. novel trip device and a time-delay device of the liquid dashpot type wherein time delays of different durations are provided by the operation of one or more valves for admitting liquid to said dashpot, at least one of the valves being operated electromagnetically in response to overload currents of a predetermined magnitude.

Another object of the invention is to provide a circuit breaker having a trip device embodying a. novel time-delay device comprising a dashpot in which time delays of different dura- -f tions in different ranges of overload currents are provided by admitting liquid to the dashpot at different rates and in which instantaneous tripping is eifected by admitting a gaseous fluid to said dashpot.

Another object of the invention is to provide .a circuit breaker embodying a novel time-delay device wherein time-delay tripping is eiiected by admitting liquid to a dashpot and substantially instantaneous tripping' is effected by admitting air to the dashpot.

Another object or the invention is to provide a circuit breaker embodying a novel trip device and a time-delay device of the liquid dashpot type having separate valve means for control- .ai

ling the admission of liquid from a liquid storage chamber to said dashpot to provide time-delay actions of different durations and having adjusting means for adjusting the amount of opening of the valve means to vary the amount of time delay provided by each valve.

Aiurther object of the invention is to provide a circuit breaker embodying a novel trip device and a time-delay device of the liquid dashpot type having a liquid storage chamber and a plurality of valves for controlling the admission of liquid from said chamber to said dashpot, certain of said valves being operated electromagnetically, adjusting means for adjusting the amount of opening of certain of said valves and other adjusting means for selecting the minimum overload current required to operate certain of said valves.

Another object of the invention is to provide a circuit breaker embodying a novel trip device having a time-delay device providing time-delay tripping of different duration for different ranges of overload currents as well as instantaneous tripping, separate adjusting means for varying the amount of time delay in each range and separate adjusting means for selectively determining the minimum overload current requirement for each range of time-delay tripping and instantaneous tripping, all of the adjusting means being disposed for easy access.

The novel features that are considered characteristic of the invention are set forth in the appended claims. The invention itself, however, both as to structure and operation, to gether with additional objects and advantages thereof, will be best understood from the following detailed description of a preferred embodiment thereof, when read in connection with the accompanying drawings.

In said drawings:

Figure l is an elevational view partly in section of a circuit breaker embodying the principles o1" the invention;

Fig. 2 is a vertical sectional view through the trip device taken substantially along line II--II of Fig. 3 and looking in the direction of the arrows;

Fig. 3 is a sectional plan view of the time-delay device taken substantially along line III-III of Fig. 2 and looking in the direction of the arrows;

Fig. 4 is a fragmentary sectional View taken on line IV-IV of Fig. 3 and showing the shorttime-delay valve device and the adjusting means therefor;

Fig. 5 is a sectional view taken on line V-V of Fig. 3 and showing the pick-up adjustment for the short-time-delay valve-operating armature;

Fig. 6 is a fragmentary sectional view taken substantially on line VI-VI of Fig. 3 and showing link 63 and moves this link counterclockwise about its pivot 61 until the support member 13 resumes its supporting position below the knee pivot pin 1|. During the closing operation, the link 19 prevents collapse of the tripping toggle 596| which acts as a thrust transmitting means and moves the movable contact structure to the closed position.

The breaker is automatically tripped open by operation of the trip device I3 for any pole of the breaker. The trip device includes generally a tripping electromagnet ||3 (Figs. 1 and 2) and a time-delay device |5. The tripping magnet I |3 includes a C-shaped magnet yoke ||1. The ends |23 of the magnet yoke form mounting feet and are drilled and tapped to receive mounting bolts |25 and |21 as shown in Fig. 1.

The upper end of a stationary magnet core |29 is provided with an internal thread which cooperates with a threaded nipple |31 disposed in an opening in the magnet yoke to rigidly secure the stationary core I 29 to the magnet yoke.

Surrounding the stationary core member |29 is an insulating tube |39 around which is disposed the energizing coil |4| of the magnet.

As shown in Fig. 1, the bolt |25 which secures the upper end of the magnet yoke to the base 5 also secures the flexible conductor 39 to the upper turn of the coil |4I. The lower turn of the coil |4| is formed into a lug |43 which, together with the inner end |45 of a terminal |41 is secured to the base l5 by means of a bolt |49. A tubular member I5| (Fig. 2) of magnetic material is mounted in an opening in the lower portion of the magnetic yoke ||1 and extends upwardly :i

The trip rod ISI is moved upwardly to the trip reaker under the control of the time-delay device H5 which comprise generally, a movable abutmentl or iiexible diaphragm It? (Fig. 2) cooperating with the lower end of the trip rod and several valve elements for admitting air to the space below the movable abutment or dia phragm at various rates to provide different amounts of time delay. The iiexible diaphragm disposed in a chamber formed in an upper housing member ill and a lower housing member H3, both of said housing members being formed of molded insulating material. The outer edge of the diaphragm |21, together with a sealing gasket |15, is clamped between the housing members to form airtight seal. The housing members i12-|13 are secured together and rigidly secured to the magnet yoke I l1 by means of bolts (not shown). The central portion ci the diaphragm |51 is clamped between upper lower clamp members Ill! and IBI, respectively. A reduced end |33 ci the trip rod I6|, entending downwardly through openings in the members |19 and I 3| and in the flexible diaphragm, is formed over against the lower face of the latter to form an airtight seal.

Since the spaces above and below the diaphragm |61 are completely sealed off from each other and the space above the diaphragm is at atmospheric pressure, any force tending to raise the trip rod |6| will be restrained by the partial vacuum below the diaphragm. In order to con trol the tripping movement of the trip rod ISI, several valve devices are provided to admit liquid from a reservoir (Figs. 2, 4, 6, '7 and 8) to the space below the diaphragm |61. The valve devices comprise a long-time-delay valve device indicated generally at |81 (Fig. 7) and a shorttime-delay valve device indicated generally at I (Fig. 4.). There is also provided an instantaneous valve device ISI (Fig. 6) for admitting air from the space above the diaphragm to the space below the diaphragm to permit instantaneous operation of the trip rod |6I.

The long-tinie-delay valve device (Figs. 3 and 7 .i comprises a valve rod |93 slidable axially in an opening in the upper wall of the reservoir |85 and having a tapered lower end forming valve which cooperates with a valve seat |51 formed in the lower housing member |13 to control a passage |28 communicating the reservoir |85 with the space below the diaphragm. The amount of opening oi the valve I95-I91 is manually adjusted by means or an S-shaped adiustable member ISS, the upper horizontal portion 20| of which engages an annular groove in the upper end of the valve rod |93. An adjusting screw 265 threadedly engages a central cross member 261 of the adjustable member and passes through an opening (not shown) in a lower horizontal member 239 which has a reduced portion 2li extending through a slot 2|3 in a scale plate 2|5 mounted on the housing members |i| and il?. The adjusting screw 265 has a shaft portion 2 l' rotatably supported in the housing member |13 and has a. knob 253 rigid therewith for manually rotating the screw. Rotation of the screw 205 will move the adjustable member |96 up or down, depending on the direction of rotation, and move the long-time-delay valve i523 up or down to vary the amount of opening thereof. This varies the amount of time delay provided by the long-time-delay valve device Iii?.

The pick-up point of the long-time-delay tripping may be varied by varying the tension oi a biasing spring 22| (Figs. 2 and 3) which biases the main armature |53 against attraction. One end of the spring 22| is hooked in opening in the bight of a U-shaped lever 223, the legs 225 of which are pivotally supported in openings in an upwardly extending portion 221 (Fig. 2) of the housing member |1I. At its right-hand end, as viewed in Figs. 2 and 3 the lever 223 is bifurcated and is provided with inwardly extending projections 229 which engage in an annular groove 23| in the armature |53. The other end of the spring 22| is attached to the vertical portion oi an angular adjustable member 233 hav ing horizontal portion 235 threadedly engaged by an adjusting screw 231. The portion 235 is provided with a reduced end 239 which proiects through a slot 24| in the scale plate .2!5 to indicate the setting of the device. The screw 231 has a shaft portion 243 rotatably mounted in tl e lower housing member |13 and a knob 21.55 on the lower end of the shaft portion for manually rotat ing the screw 231. It will be obvious that rotation of the knob v245 and screw 231 will move the member 233 up or down, depending on the direction of rotation, and vary the tension of the spring 22| thereby varying the magnitude of overdaad current rqu 'ed to operate the arma- Tne shortiumeaeiayvaive.device iss (Fig. e) comprises a'vva'l've ineinberj'i slidable vertically in jan opening in the upperwail of the reservoir |85 and having avvral've l2119 on the lower end thereof cooperating with a' valve seat 25| to control a passage 253 communicating the reservoir rec with the space below the diaphragm.

The shortt'imedelay valve 24| fis adapted tobe opened byA means of nan ar'mature 255 (Figs. 3 and 4) operated upon ener'gization of the tripping electromagnet 3 (Figsrl and 2) in r-esponse to= Overload Cu'rre'ntsef, .predetermined value- The armature e is pivotallys'upported at its rightf hand end (Fig. 3) by meansrof projections 257 on the armature engaging in recesses 259 in the housing member KI'U.v The armature 255 is provided with anA opening 26| "for receiving ahead 253 of the valve 241 and 'the opening 26| has a narrow portionv 26:5`` for` engaging an annular groove Ztlv formed, by the head 253 and a collar 269 onthe valveZlifL i Y The armature 255 is biased against attraction by means ofa vspringv 2li Iig. 5) having one end attached to `a projection 2150i thearmature and the other( end attachednto an adjustable member 25. Y The adjustable member 'threadedly engages an adjusting screw 271 having a shaft portion 215 rotatably mounted `in'the,lower housing member |13 and provided with a manual knob 28| for rotating the screw 2|| to` vary the tension of the spring *'21 to thereby vary the `minimum overload current requiredutonoperate theuarmature 255. The adjustable kmember 2'i5has" alre'duced pointer 283 extending through a slot 235m the scale plate f2|5 to indicatethe adjustment of short-time-delay pick-un, Y, t. A

The 'amount ofr opening foi the short-time-delay valve device H39 ajnd-, h'ence, the amount of time delay providedjbyhthe valve device |89 may be varied by varyingrtheextent or movement of the armature 255. Thisiseffected by means of an S-shapedhadjustable stop member 281 (Figs. 3 and .4). The upper end ofthe member v281 is formed over or at `259 toprovide an adjustable stop vfor the armature25'5lw'1he central cross member 20| oigthenijemberlZS] is threadedly engaged by an adjusting screw2l93 lwhich `extends i downwardly through a clearance Qpening in the lower memberhZlSTi ofthe Sfsha'ped member and has a 'shaft-portion 201 rotatably mounted inthe lower housing member |15. '1*lie lowern 1`ember 295 of the -fsh'ap'ed member has a reducedy end 259 projeotingthrough a Vslot 30| in the scale plate to act as a pointer for "inc'icatingi thetimef'- delay setting of the short time delay. A knob 3073 is provided onth'e lower end of the shait portion -29? for manually rotating Ythc/screw to adjust the stop 239. 'I'he'Stdp 289 'iS disposed il thpath of a projection 305 '(Fi'gs. `3 ande) 'of the armature 255 and adjustment of the stop 289 will permit 'a greater oriesser Tmovementfof the arma'-A ture and opening of the valve'249-25 thus varyg currents, it is desired ot tripthe breaker substantaiiy instatanusn. *such 4liquids are, by rea'- son of their cw new yleity, unsuiteu for instantar'ienu's tripping operations. In 'order to provide instantaneous tripping foi the l'nreaker, the instantaneous valve device |5| (Fig. 6) is arranged to control a pa'ssageor 'adrriitting air from the space 'above the diaphragm to the 'Space below the diaphragm; the' high ilow velocity 'of air or other suitable gas permits unretarded tripping 'operation of the trip` device. Y

Referring to Fig'. 6, the 'instantaneous valve device |9| comprises a valve member 3G?! s'lidable vertically in an 'opening in the upper housing member An 'annular Valve facing 305 seated in an Vanni'ilar groove in thelow'er end of the valve Vrnjernlrer,3077 cooperates with valve seat 3|| 'formed in the housing member I'H to control a. passage 3| 3 communicating with the space above the diaphragm I'S'ijand a passage SI5 co-; vnruinicating :with the space below the diaphragm. The valve 30 is operated to the 'open position by means of an armature 3|?1 (Figs. 3 and 6) pivotallydsupportejd at its vright-hand end by means ofhprojeetionsljengaging in recesses 52| in the uppervhousingmeinber |`i|. The armature 3V! is provided withfah open slot 323 which 'engages anan'nular groove 32(5 fo1'med on the valve member enz 4by a head 32? and a cenar 32e. 'che armature 3U Ais biased against attraction by a spring 33| having one 'end attached to the arma- Atlirey Sl'lnby means of` a clip 333 and the other "end attached to an adjustable member 335. The adjustable member `7.1?35 is threadedly engaged by an adjusting screw 331 having a .shaft portion see rotatabiymounteuin the 'housing member |13. A knob v54| is provided on the lower end of the shaft 339'. The adjustable member 335 is provided with 'a reduced portion which 'extends through Va 'slot ,345 in the scale plate 2|5 to act as aI pointer forindicating the pick-up adjustment vof* thearinature 3|?. The pick-up point of the" instantaneous trip armature 3i? is aoljusted byrotating 'the knob 31H to vary the tension of the sprin'g33 The trip device operates with time delays ci diiereht duratens in two distinct ranges of overcurrents below 'ai predetermined magnitude: and instantaneously in response to overc'urrents 'above the predetermined magnitude, or in response to short circuit currents. The ranges of overcurrents may be arbitrarily dened as, for example, a low range up to 500% or 660% of normal rated current, an intermediate range between 509% or 600% and 10 00% of normal rated current, and instantaneous 1000% or more of normal rated current. y

Assuming an overcurrent Within the low range 'of overcurrents, the trip device (referring particularly to Fig. l0) will operate as follows: Upon the occurrence of an overcurrent in the low range, the tripping e electromagnet ii becomes energized and attracts the armature upwardly. The armature acts through the spring 53 tc produce an upward thrust on the trip rod iti, the movement of the trip rod being retarded by the partial vacuum below the diaphragm iti. The trip rod 'IGI moves slowly in 'tripping direction as liquid is 'drawn into 'the space below the diaphragm from the reservoir '|25 through the longtime-'delayvalve |95-E'2'Z (Fig. 7) until the upper end the trip rod engages the headed screw 99 .'(Fig: Yl) and'aetuates the latch mechanism to effect tripping the breaker in the manner previously*describedr`- The time delay provided by the 1ng'-time'-de1ay device ser is in the order of seconds and may be varied by adjusting the valve |95|91 (Fig. 7) as set forth previously.

As soon as the breaker contacts are opened, the tripping magnet ||3 is deenergized and the armature |53 and the trip rod |6| are restored by means `of the spring 22| and the force of gravity to their Fig. 2 positions. A ball check valve 34E (Fig. 8) controls a passage 349 from the space below the diaphragm |61 to the reservoir to provide for quick restoration of the armature |53, the trip rod |6| and diaphragm |61 to their normal positions following a tripping operation.

When an overcurrent occurs in the intermediate range of overcurrents, the electromagnet H3 is energized suiiiciently to attract the short-tiniedelay armature 255 (Figs. 3 and 4) upwardly against the adjustable stop 289 opening the shorttime-delay valve member 241 an amount determined by the adjustment of the stop 28S. This admits liquid from the reservoir |85 to the space below the diaphragm |61 at a much higher rate than the long-time-delay valve alone and provides a relatively short time delay in the order of cycles in the tripping operation.

Energization of the tripping magnet lf3 in response to an overcurrent in the intermediate range is not suincient to attract the armature 3H for the instantaneous valve 301 (Figs. 6 and 10). However, upon the occurrence of an overcurrent of 1000% or more or" rated current, both the short-time-delay armature 255 and the instantaneous armature 3|1 are actuated and open both the short-time-delay valve device |89 (Figs. 4 and 1G) and the instantaneous valve device IBI (Figs. 6 and 10), thereby admitting both liquid and air to the space below the diaphragm |61 at a rate sufficient to permit substantially instantaneous tripping movement of the trip rod il. Since the long-time-delay valve device |31 (Fig. 7) and the short-time-delay valve device |89 (Fig. ll), as well as the instantaneous valve device I9! (Fig. 6), are open on instantaneous tripping operation, a certain amount of liquid from the reservoir |85 Will be drawn into the space belovv the diaphragm |51 von such operations. Due vto the relatively high flow Velocity of air as compared to liquids, the amount of liquid drawn into the space below the diaphragm will be relatively small. It will be seen, by reference to Fig. 8, that the passage 349 will, upon restoration of the trip rod IGI and the diaphragm, bleed olf the air admitted to the space below the diaphragm on instantaneous tripping operation so that any negligible quantity of air remaining below the diaphragm will not affect subsequent longor short-time-delay tripping. A passage 35| (Fig. 4) permits the air nowing out through check valve 341 (Fig. 8) into the reservoir |85, to return to the space above the diaphragm |61.

On short-time-delay and instantaneous tripping operations, the spring |63 limits the force applied by the moving armature |53 to the timedelay device. On such operations the armature |53 is attracted immediately against the fixed core member |29 compressing the spring |53 which then supplies the force necessary to actuate the trip rod. Thus, the pull exerted on the time-delay device is limited to the maximum force exerted by the spring |33 when it is compressed. This prevents damage to the time-delay device and also provides a uniform pull on the timedelay device.

The herein-disclosed circuit breaker is well adapted for the protection of distribution systems. Such distribution systems are usually 10 protected by a series of breakers including generator breakers, bus tie-in breakers, feeder breakers and load breakers. The circuit breakers of such a system are usually set for selective tripping, that is, if a fault should occur at any point in the system, the breaker nearest the fault and on the generator side of the fault should open to clear the fault condition.

The time-current requirement of the tripping device varies with the position of the breaker in the selective system for which reason a trip device providing a wide range of adjustment is essential.

As shown in Figure 9, the trip device is capable ci" a Wide range of adjustments. There are five separate adjusting devices all located for ease of accessibility. By Way of example of the ranges of adjustment, the following have been arbitrarily selected for illustrative purpose:

i. Range of long-time-delay pick-up, from to 160% of coil rating.

2. Range of long time delay, from 2S to 86 seconds.

3. Range of short-time-delay pick-up, from 500 to 1000% of coil rating.

4. Range of short time delay, from Li to 30 cycles.

5. Range of instantaneous pick-up from to per cent of coil rating.

Fig. 11 graphically illustrates the ranges of the several adjustments of the trip device. Along the left-hand edge of Fig. 11 is indicated the time in seconds. At the bottom is indicated the per cent of coil rating and along the right-hand edge is shown the time in cycles based on Gil-cycle frequency. The curve A represents the minimum settings of the adjustments and the maximum settings are represented by the curve B. By adjusting the knob 245 (Figs. 2, 9 and 10), the longtirne-delay pick-up may be adjusted to pick up at any point in the band of adjustments defined by curves A and B as indicated at C, that is, by way of example, `between 89% and i60% of coil rating. Adjusting the knob 2li) (Figs. 7, 9 and l0) which controls the long-time-delay valve |93 varies the amount of long time delay between 23 and 86 seconds as indicated at D in Fig, 1l. As indicated at E (Fig. l1) the short-tiine-delay pick-up may be set to pick up between 500% and 1000% of coil rating. This is effected by adjusting the knob 28| (Figs. 5, 9 and 10). The amount of short time delay may be varied between 4 and 30 cycles, as indicated at F, by adjusting the knob 303 (Figs. 4, 9 and 10). Finally, the instantaneous pick-up point may be varied between l000% and 1500 of coil rating, as indicated at G, by adjusting the knob 34| (Figs. 6, 9 and 10) which controls the tension of the biasing spring 33| (Figs. 5 and l0) for the instantaneous valve-operating armature 3|1.

Each of these adjustments may be made by merely turning the adjusting kno-b associated with the particular adjusting devices previously described. The adjustments are independent of one another and, as shown in Fig. 9, all of the adjusting knobs are conveniently located.

The complete adjustability of the trip device eliminates the necessity of increasing band width of adjustments to compensate for manufacturing variations and different coil ratings.

Having described the invention in accordance with the patent statutes, it is to be understood that various changes and modifications may be made in the structural details and combination of elements disclosed without departing from some of the essential features of the invention.

"We claim as our invention:

el'. AfIn anelectromag'netic trip devicelcomprising a Ytripfrod, an energizing Winding, 'an armature operable upon energization'ci 'said winding qin response-to overload cur-rents'to actuate said trip rod, atime-'delay elementlfor retarding tripping operation of said trip' rodfa Ahousing defining Aa chamber for said time-delay elementl and a `separateiiquidstorage reservoir, -'a plurality' oi passages communicating said, reservoir and said chamben'yalve 'means `controlling said passages to admit-liquid -f-rom said-reservoir to said Acliarnbe: at 'different rates toeiect time delays of'diierent durations-in fthe operation 1of said trip rod and electromagnetic lmeans-forv actuating said valve means. Y

'afinar-1 electromagnetic -trip device comprising a trip rod, an Aenergizing Winding, anv armatureV operable upon energization of said Winding in resio'rise'to` overloadfcurrents-tcactuate said trip rod, a` time-delay element -fr-retarding" tripping operation fof said trip r'od,-'a =licu`sing 1vdefining a chamber for said time-delay element and arseparate l'liquid'storage reservoir; a :plurality of passages communicating saidre's'erv'oi-r v'and said chamber, and valve means controlling saide-passages to 'admit liquid'ffrom fsaid reservoir vto said chamber at diierentates- -toi eiccttiincfdelays of diierent rates to eect time delays or" different duration' nth "'ope tin-fr Asaid' trip 'rod,'a"s'epsage' oxmuniaungsaidchamber teati daw,

said-1 trip; rod, van enclosing-housing defining a ser tla predeterminada@ to ensei. ai ,reiatiyeiy long timede'lay in the tripping movement oi said tp red," wed'valva; anden. elrneiureA 09erableautomaticallyby said electromagnetic Y trip de cefinv responseito-abnormal cirouitconditions toactuate said second vaive and `increase tl'ie rate ofadmission gij-liquid from said'reservoir to said chamber ,tof effect arelatively' short time` delay in the tripping, movementofsaid `trip rod. n

4. -Inj anfelectroinagnetic trip'- device comprising atripi member, an .energizing winding-fan armature' operable upon energia-ation' ci said winding ftd v-actuate Y- said tripf member, 1 a timedelay, elementi ccmprA-isingf-ahiexibie diaphragm foi-retarding 'tripping vmovement or" lsaid trip member, a chamber, a reservoir containing liquid, a iirstvalve means 4for `adrififi-tting liquid irornfsaid reservoir to-'said chamber at ia predetermined rate to,- rretardmovement of' said'- ytrip -niemb'er Withg-ai; predetermined time 'delayf-a second' valve means, andv a second armature operated in frespense tolpredeter'mined vabnormali circuit conditionstoractuate saidtsec'ond valve meansand increasethe rate ofv'ad'mission ofjfliquid V-f-r'om`l said Areservoir-to saidchamber.

5. A trip device 'for-a circuitibreakercomprisingI a tripfmember, electroriia'gne'tic means operable'when-energized in response -tofcverioad curvrentsto actuatei V"said `Vtrip Y member, time-delay means comprising a 'dashpot 'for retarding tripping movementfoff'said trip''member,' a' housing delining af's'eparate reservoir "containing: ai`V liquid,

i2. means `deiining a Yrestricted passage admitting liquid from vsaid reservoir to said dashpot ato lletard tripping movement -of `said trip member withfa relatively long :time-delay when :said-electromagnetic means is energized-in response-toeren overload current below -a predetermined value, means dening a `second passage-communicating said dashpot to atmosphere, `and avalve .operable by said electromagnetic means Whenxsaid electromagnetic means is energized in response to an overload vcurrent above said predetermined value, said Valve opening `said second passage to admit air to said dashpot to Ypermit:saidfe'lectromagnetic means to actuate saidA trip member substantially instantaneously.

6. In a circuit Vbrealrerhaving relatively movable yContact means and operating lmechanism therefor, the combination "of :a 'trip member, fa trip device comprising-electromagnetic'means-operable when 'energized in 'response to overload currents to actuate'said trip'-memben-time-delay means comprisinga dashpot for v retarding tripping movement 'of said f tripmember, :a: housing for said dashpot Avie'iining a yseparate"reservoir containing a liquid, m'eans Y'defining a restricted passage admitting Aliquid from said reservoir ito said dashpct to retard tripping movement of-said trip member Whe-nsaidielectroinagnetic means is energized in responseto an overlcadcurrent-below f a 'predetermined value; means f deiining'A a second passage communicating said =dashpet-to`1the atmosphere, and'fa valve operable-by-said-electro magnetic means when' said electromagnetic means is energized in response-toan'overlead current above said predetermined value, said-valve opening said second passage to admit airtov said dashpot to permit said electromagnetic rm'aans tolactuate said trip member substantially Vii'is'tan'tarieously.

7. In a'trip' deviceior'facircuit break'erythe combination of' trip rod, electromagnetic means for actuating said trip rod, tinie-delay-means comprising a'da-shpot for retarding'trippingmcvement of` said trip rod, `av reservoir containing'ia supply of liquidya'iirst valve`V for admitting liquid from saidreservoiito said dashpctat a predetermined rate" for' effecting" a' long time delay-of the orderof secondsin the "operationy oil-said trip rod,A a' second valve'jforiadmitting liqiid'fromsaid reservoir" to said dash'pot atagreater ratethan' said rst Valve for'effecting a short `Vtime L delay ofthe orderoi" cycles'in` the'operationv of said ,trip rod, and a third 'valve fonadrnitting airtozsa'id dashpot at a rate'to permitsubstantially `insta-ntaneous' operaticn'of said trip rod.

8.7In a circuit'breaker havingrela'tivelymovablecontactmeans and operating' means therefor, the combination of trip' means, electrores'p'onsive means" for' `operating"said trip" means, timedelay means comprisingV aA da'shpot'for retarding tripping operation of Vsaid trip means, a. liquid storage chamber, riirst valve'rn'eansior admitting liquidy from saidfstorage. 'chamber'fto said d'a'shpot Vat a predetermined'rate for effecting a long time'delay of the 'order' of seconds in theope'ration of said tripmeans, a second valve means 'for admitting liquidfrom said storage "chamber to said dashpot at afgreater rate' Vth'an's'aid first valve Vfor effecting a short time delay of 'theor'der ofl cycles in the' operation of said trip means, a iirst armature 'operable'whensaid ele'ctroresponsive means is energized in response to overload Acurrents -belowa predeterminedvalue for actuat- Eing-'said second valve;` a'thirdlval-ve 'for admitting air to saidV daslipot at a ratefto permit'insta'iita- T13 neous operation or said trip means, and 9, second ai rature operable when said electroresponsive means is energized in response to overload currents above predetermined value for actuating said 'third valve.

Q. In a circuit breaker having relatively movable contact mea-ns and operating means therefor, the combination of a trip member, electromagnetic trip for operating said trip member, time-delay means comprising a daslipot for at times retarding tripping operae tions or said trip member, a, rst valve means for admitting liquid to said dashpot at a. predetermined rate for enecting a time delay in the operation of said trip member, e, first armature operable said electromagnet is energized in response to overload currents belovv a predetermined value for opening said iirst valve means, a second valve means for admitting air to said dashpot at a rate to permit instantaneous operation of said trip member, and a second armature operable Wnen said electromagnet is energized in response to overload currents above said predetermined value for opening said second valve means.

10. An electromagnetic trip device having a trip member, means for operating said trip member, time-delay mea-ns comprising a dashpot for at times retarding tripping operations of said trip member, a nrst valve means for admitting liquid to said daslipot at a predetermined rate for effecting a time delay in the operation of said trip member, a first armature operable when said electromagnet is energized in response to overload currents below a predetermined value for opening said iirst valve means, adjusting means for selectively determining the extent of opening of said iirst Valve to thereby vary the amount of time delay, a second valve means for admitting air to said dashpot at a rate to permit instantaneous operation or said trip member, and a second armature operable when said electromagnet is energized in response to overload currents above said predetermined value for opening said second valve means.

1l. In a circuit breaker having relatively movable contact rneans and operating means therefor, the combination of a trip member, electromagnetic trip means, means for operating said trip member, time-delay means comprising a nuid dashpot for at times retarding tripping operation L oi said trip member, a reservoir separate from said dashpot and containing a liquid, a first valve means for admitting liquid from said reservoir to said dashpot at a predetermined rate for effecting a time delay in the operation of said trip member, a rst armature operable when said electromagnet is energized in response to overload currents below a predetermined value for opening said first valve means, a second valve means for admitting air to said dashpot at a rate to permit instantaneous operation of said trip member, e, second armature operable when said electromagnet is energized in response to overload currents above said predetermined value for opening said second valve means, and separate adjusting means for said nrst and second armal tures for selectively determining the minimum overload current required to actuate said armatures.

12. In a circuit breaker having relatively movable contact means and operating means therefor, the combination of a trip rod, an energizing winding, a main armature operable upon energization of said winding in response to overload Cil currents to actuate said trip rod, time-delay means comprising a fluid dashpot operated by said trip rod for retarfling operation of saitrip rod, a storage chamber containing liquid, iirst valve means controlling a passage for admitting liquid from said chamber to said dashpot at a predetermined rate for eiiecting a time delay in the operation of said trip rod when said winding is energized in response to overload currents belotv a predetermined value, a second valve means controlling a second passage for admitting air to said dashpot at a rate to permit instantaneous operation of said trip rod, a second arma ture operable when. said winding is energized in response to overload currents above said predetermined value to open said second valve, and resilient means disposed between said main armature and said trip rod to limit the force applied by said armature to said trip rod.

13. In a trip device for a circuit breaker, the combination ot a trip rod, an energizing winding, a main armature operable upon energization of said winding in response to overload currents to actuate said trip rod, means adjustable to selectively determine the minimum overload current required to actuate said main armature, time-delay means comprising a dashpot including a movable abutment attached to said trip rod for retarding operation of said trip rod, a liquid storage chamber separate from said dashpot, a rst valve means for admitting liquid from said storage chamber to said daslipot at a predetermined rate for eliecting a time delay in the operation of said trip rod when said winding is energized in response to overload currents below a predetermined value, a second valve means for admitting fluid gas to said dashpot at a rate to permit instantaneous operation of said trip rod, a second armature operable when said winding is energized in response to overload currents above said predetermined value to open said second valve, and means adjustable to selectively determine the minimum overload current required to actuate said second armature.

14. In an electroresponsive trip device comprising a trip rod, an armature operable to actuate said trip rod, spring means disposed between said armature and said trip rod to limit the force applied by said armature to said trip rod, time-delay means for retarding tripping operation of said trip rod comprising a dashpot, a housing for said dashpot, a liquid storage chamber dened by said housing and containing a liquid, normally closed valve means controlling a passage and operable to admit liquid from said storage `chamber to said dashpot at a predetermined rate, a valve-operating armature operable upon energization of said electroresponsive means in response to an overload current of predetermined value to open said valve, an adjustable stop for limiting the opening movement of said valve-operating armature, and adjusting means for varying the setting of said adjustable stop to vary the extent of opening of said valve and the amount of time delay provided thereby.

JOHN B. MACNEILL. WILLIAM H. S'IUEILEIN. MERL E. HORN.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 2,451,962 Lindstrom et al Oct. 19, 1948 2,486,596 Graves Nov. 1, 1949 2,543,410 Jensen Feb. 27, 1951