US2534933A - Circuit interrupter with speed control of contact - Google Patents

Description

Dec. 19, 1950 R, c, VAN slCKLE 2,534,933

cxacun INTERRUPTER WITH SPEED CONTROL OF CONTACT Filed Nov. 6, 194a 2 Sheets-Sheet 1 23 i l L FL. L.: 4010' 25 m? 27 703 E L I k 93 fi-l? E 2 L5 Q; Q) 3* l9 Closed 0 en Posztwn afLzft Rod P WITNESSES: INVENTOR Roswell C. Van Sickle.

ATTORNEY Dec. 19, 1950 R. c. VAN SICKLE 2,534,933

CIRCUIT INTERRUPTER WITH SPEED CONTROL OF CONTACT Filed Nov. 6, 194a 2 Sheets-Sheet 2 II I l/ I II I l/Il/f/ III/ l/ l I lI/l/I/l/l/ I I l l WITNESSES: I8 INVENTOR M M Roswell 0. Van Sickle. W

ATTORNEY Patented Dec. 19, 1950 UNITED STATES PATENT OFFICE CIRCUIT IN TERRUPTER WITH SPEED CONTROL OF CONTACT Roswell C. Van Sickle, Pittsburgh, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application November 6, 1948, Serial No. 58,763

8 Claims.

ing operations. It is an object of the present invention to control the moving parts of a circuit interrupter to reduce the stresses on the parts and to reduce the energy losses due to shock and vibration.

Another object of the invention is to reduce the speed of the moving contacts of a circuit interrupter immediately before the moving contact parts touch the interrupting structure.

Another object of the invention is to increase the effective mass of the moving parts of a circuit interrupter just before the contacts touch on a closing operation to thereby reduce the speed of the moving contact.

.Another object of the invention is to provide an inertia device related to the operating mechanism of a circuit interrupter in a manner to reduce the speed oi'the moving parts of the circuit interrupter just before the contacts touch during a closing operation.

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, together with additional objects and advantages thereof will bebest understood from the following detailed descriptionof one embodiment thereof when read in connection with the accompanying drawings:

In said drawings:

Fig. 1 is an elevational view, partly in section and partly schematic, of a circuit interrupter v embodying the principles of the invention.

Figs. 2 and 3 are enlarged sectional elevational views of the inertia device taken on lines III- III of Fig. 4 showing'the inertia device respectively in the open and closed positions.

- Fig. 4 is a front elevational view showing the inertia device and a. portionof the circuit interrupter operating mechanism.

Fig. 5 is a graphic illustration of the closing speed of the circuit interrupter lift rod with and without the inertia device.

Referring to Fig. 1 of the drawings, the circuit interrupter, indicated generally at H, may be of any conventional construction either of the oil break, air break. vor gas blast type andis operated to closed position by means of a compressed gas operated mechanism indicated generally at I3 (Fig. 1).

The operating mechanism includes a main casting l5 which is formed to provide an operating cylinder I! closed at its upper end by an integral portion of the main casting IS. The

lower end of the cylinder I! is closed by means of a member I!) suitably secured thereto and provided with a relatively large port 2| which is open to the atmosphere. An operating lever 23 is pivotally mounted at one end on the casting i5 and consists of a pair of spaced parallel levers (only one being shown) connected at one end by a pivot pin 25 to the upper ends of spaced parallel links 21. Thelower ends of the links '21 are pivotally supported by means of a pivot pin 29 on ears 3| (only one being shown) formed on" the main casting IS. The free ends of the operating levers 23 between them carry a short shaft 33 upon which is mounted a latch roller 35 disposed between the levers 23.

The circuit interrupter II is biased to open 3 position by means of an accelerating spring 31 and is connected to the operating mechanism l3 by means of an insulating lift rod I49 (Fig. l), a lever system indicated generally at I41, a horizontal pull rod III; a leversystem I09 and an operating rod 39 pivotally connected to the operating lever 23 by a pivot pin 40.

In order to hold the interrupter closed, following a closing operation, the operating lever 23 is releasably held in closed position by means of a latch mechanism indicated generally at 6|. The latch mechanism comprises a main latch 63 pivotally supported on the main casting l5 by means of a pivot pin 65 and biased to latching position by a spring 61. The latch 63 is adapted to engage the latch roller 35 carried by the operating lever to restrain the operating mechanism and the circuit interrupter in closed position. The main latch 631s of the slip off type and will not, by itself, hold the operating lever in closed position for-which reason there is provided an auxiliary latch 69 which engages and holds the main latch in latching position. The auxiliary latch 69 is pivotally mounted on a pin Hon the main casting and is biased by means of a spring 13 to latching position.

A holding lever 15 pivoted on the pin "H and biased by a spring 17 is provided to hold the auxiliary latch 69 in unlatched position when the interrupter mechanism is out of the closed position.

An electromagnetic trip device indicated generally at 83 is provided to actuate the latch frees the main latch 63 and permits opening movement of the operating rod 39and the interrupter mechanism.

The breaker operating rod 39 is connected at its upper end through the lever system indicated generally at I99 (Figs. 1 and 4) to the horizontal pull rod III. The lever system I09 is enclosed in a housing I I3 having a clearance opening in the bottom through which the operating rod 39 extends. the operating rod 39 within the housing H3 is a clevis H5, the two arms of which are connected by means of a pivot pin IN to a pair of reversed bell cranks H9. The bell cranks H9 are mounted for pivotal movement on a pin 12I having one end mounted in a bearing I23 secured. to the right side plate (as viewed in Fig. 4) of the housing H3 and the other end supported in a plate I25 secured to the back plate of the housing (Figs. 1 and 4).

Each of the bell cranks I I9 comprises a short armIZ'I and a long arm I29, each of the arms of the clevis I I5 being disposed between the long and short arms of its associated bell crank II9 (see Fig. 4). The lower end ofa link I3! is disposed between the free ends of the long arms 129 of the bell cranks H9 and is pivotally connected thereto by means of a pin I33. The upper end of the link I 3| is pivotally connected by means of a pin I to one arm of a bell crank comprising a pairof bell cranks I31 disposed one on each side of the link I3I and rigidly secured to a rectangular shaft I 39. The shaft I39 has reduced ends and is rotatively mounted. in bearing plates I IIsecu -ed tothe innersides of the side plates ofthehousing, II3 (Fig. 4). The 1 other arm of the bell crank I31 is connected by means of a pivot pin I431 to the horizontal pull rod III. l Thus the Vertical movement ,of the operating rod 39 is transmitted through the lever system I09. to actuate the pull rod HI to close the interrupter.

' The circuit breaker may comprise two or more poles, each pole being disposed in its own separate tank, a fragment of which is shown at I45 (Fig. 1). Each pole of the breaker includes a pair of interrupters II but sincethe interrupters II are all alike, only one has been shown. The horizontal pull rod. III extends to each of the poles to effect simultaneously operation of all of the poles of the breaker. The pull rod. III is connectedthrough the lever systems (only one of which is shown) indicated generally at HIT (Fig.1) to the breaker lift rod I49 for each pole for actuating the interrupters II. 1

The interrupters II maybe of any desired type, the preferred type being that disclosed in Patent No. 2,420,888 issued May 20,1947, to W. M. Leeds and assigned to the assignee of the present invention. Only a brief description of the interrupter will be given herein. Reference may be had to the above noted patent for a more complete understanding of the interrupter.

The interrupters II are supported .on-theiinre s ofi ula ir s bu hi s 4 (only a fra ment of one being shown) extending through and supported on the cover of the tank I45. In

Secured to the upper end of draws the lift v rod I 49 andthe the closed position the two interrupters II are electrically connected together by a conducting crossbar 43 secured to the lower end of the insulating lift rod :49 and a pair of movable contacts 45 (only one beingshown) disposed on the outer ends of the cross-bar 43. Disposed within a pressure generating chamber 41 is a pivoted pressure contact 49 and an intermediate contact 5|. The pressure contact 49 is actuated by an insulating operating rod 53. A compression spring biases the operating rod 53 downwardly to efiect opening movement of the pressure contact upon opening movement of the cross-bar 43. An adjusting screw 57 and a lock nut 59 therefor, is provided on the lower end of the operating rod 53 to accurately adjust the position of the contact id in the closed position.

Thelever system I4? is enclosed in a housing iz'il (Fig. 1) secured to the top of thetank I45 and comprises and arm I53 having a pivotalconnection indicated at I5 1 with the horizontalpull rod ill andrigidlysecured to a shaft 155 which is pivotally supported in the sides of the housing I5I. An arm 15?, also rigidly secured to. the shaft I5 5, has its free endconnected by. m ans of a link I59 to a lever Iiil at a point substantially midway between its ends, the, link I59 be.- ing pivotally connected by means of a pin I63 to the 'free end of, the ann i5] and by meansof a pin N55 to the lever IGI. The lever. ISI is suspended by means of links. itl and Itflin a manner to impart a straight line vertical movement to the lift rod Ill-9. for opening and closing the interrupter contacts. The lever-I6? is pivoted on a fixed pivot pin II I supported in'the sides of the housing I5I andis pivotally connectedto the lever IGI bythe pivot pin I65; The lin k IBQ is pivoted on a fixed pivot I13 also supported; in the sides of the housingilil and is pivotally connected by means. of a pivot pin I15 tonne end of the lever IBI. The .other' end of the lever i5! is pivotally connected by means of a ping I'I'I to the upperend of the lift rod I49. 5;

Downward movement of the operating rod 99 actingthrough the lever system I09 moves the horizontal pu l rod toward the left as viewed in Figure 1. This movement of the pullrrod III acting through the connection 454 rotates the arm I53, shaft I55 and arm i51 .in a. counterclockwise direction and draws the;link,l;59 up.- wardly. This pulls the lever I6I :upwardlyend the lever, swinging on the links I61; and I69 I cross-bar 43i upwardly to close the contacts.

During the upward orolosing movementofthe lift rod me the cross-bar first picks up the operatingrod 53am. moves it upwardly; therewith to actuate the pressurecontact 9 to the closed position. Thereafter the movable contactfiflxengages and movesthe intermediate contact .5 I into engagement with the pressure contact 39 .to close the circuit through the interrupters I i The interrupter is adapted. to be closed by com.- pressed gas admitted. to .thecylinder I7 above the operating piston 93.; The piston is secured. to .a piston rod siidable through an air-tight open ing in the top of thecylinder. A connector 9! is threadedly connected to the. piston rod 95 and to the operating rod 39. .The connector 97 is also pivotally connected to the operating lever 23 by a pivot pin 49 thusdirectly connecting the piston 93 to theoperating rod'39 andto the-lever 23. 1 Compressed. gas is admitted from an auxiliary portion of the closing stroke.

reservoir to the upper end of the cylinder I1 through an inlet passage IilI which is controlled bya main inlet valve I93. The opening operation of the inlet valve I93 is, in turn, controlled by an electromagnetically operated pilot valve 195.

The pilot valve I95 is operated by an electromagrlet I91 which, when energized, causes opening of the pilot valve I95 to admit compressed gas from the reservoir 99 to operate the main inlet valve I93. Actuation of the inlet valve admits compressed gas to the upper end of the operating cylinder I1 which drives the piston 93 and the operating rod 39 quickly downward to close the interrupter.

When the mechanism is operated to closed po v 'sition, the latch roller engages the inclined surface of the main latch 63 and moves the latch counterclockwise until the roller passes the nose of the latch. The spring 91 thereupon restores the main latch to latching position. p y The operating cylinder is also provided with an exhaust valve (not shown) for quickly reducing the pressure on the working side of the piston to permit high-speed opening of the circuit breaker.

The exhaust valve is operated to open position aforementioned patent.

During a closing operation of a compressed gas operated circuit breaker the greatest force of the operating mechanism is required during the latter Before the moving contact structure picks up the interrupter mechanlsm during a closing operation the moving contact moves relatively freely and acquires a high velocity. If the moving contact structure picks up the interrupter mechanism while travelling at high speed, severe stresses, excessive slamming of the parts and energy losses will result. This is particularly true in the type of circuit breaker illustrated when the rapidly moving cross-bar 99 engages the interrupter operating rods 53 hearing in mind that there are two interrupters IIfor each pole of a three pole breaker. Consequently, the moving contact structure, whiletravelling at high speed, must suddenly pick up six interrupter mechanisms. An important feature of the present invention is the provision of means for reducing the speed of the moving contacts immediately before the moving contacts pick up the interrupter mechanisms. This means comprises an inertia device shown generally at I19 (Figs. 2, 3 and 4). The inertia device includes amass IBI rigidly mounted by means of bolts I32 between the free ends of a pair'of spaced parallel levers I83 and I85. The levers I83 and I85 respectively are pivotally supported in bifurcated support members I81 and I89 on pins [9i and I93. The support member I81 is rigidly secured to the support plate I25 and the member I89 is rigidly secured to the inside surface of the side plate of the housing I I3. The levers I83-I 85 and the mass 18! are connected by means of a toggle comprising a link I95 and an arm I91. The link I95 comprises a pair of links I95 connected to the free end of an arm I91 which is rigidly secured to the rectangular shaft I39 to which are secured the arms l31 for operating the pull rod III. The links I are disposed one on each side of the arm I91 and are pivotally connected thereto'by means of a pin I99. The links I95'are pivotally'connected to the levers I83-I85 adjacent the mass I8I' by meanspf a pin, ZilI which extends through both levers l83i85'and both links I95. A spacer 293 is provided to space the links apart and the links are properly spaced from the levers HES-85 by means of spacers 295.

During a closing operation the shaft I39 is rotated counterclockwise from the position shown in Figs. 1 and 2 to the position in which is appears in Fig. 3. During the early part of the closing stroke the levers I83-I-85 and the mass I 8I rotate clockwise about the pivots I9II93 at a relatively low speed and impose a negligible restraining force on the operating mechanism. The pivot pin I99, during its counterclockwise rotation from the Fig. 2 .position, approaches a line indicated at A drawn through the pivot I9II 93 and the center of the shaft I39 as the moving contact nears the stationary contact. 'At this time the operating mechanism, acting through a very small moment arm, suddenly attempts to move the inertia device at high speed. The energy required to accelerate the speed of the inertia device causes a substantial reduction in the closing speed of the breaker mechanism including the breaker lift rod I49 just before the moving contact engages the interrupter mech- 'anism.

The energy of the closing means is not dissipated by the inertia device, but is stored therein and, after the moving contacts are brought smoothly into engagement with the stationary contacts, most of the energy is returned to the operating mechanism to assist in the final closing movement thereof. During a closing operation, the moment arm with which the arm I91 drives the inertia member I19 decreases until approximately the, time the pin I99 crosses the line A (Fig. 3). Consequently the mechanism accelerates the speed of movement of the inertia member and the inertia member absorbs energy from the mechanism up to this point. Thereafter the moment arm increases and the speed of the mass I19 is reduced hence, the energy absorbed by the inertia device up to this point causes it to attempt to move faster than the mechanism, thus exerting a pull on the mechanism assisting the mechanism in the closing operation until the pin I99 crosses the line B (Fig. 3). At this point in the operation the toggle I95-I91 is fully extended and the inertia member I19 has reached its point of greatest clockwise travel which is indicated at I83 in Fig. 3. Thereafter during the closing operation the influence of the inertia member on the mechanism is negligible.

The closing speed of the circuit breaker, both with and without the inertia device, is graphically illustrated in Fig. 5, in which the curve C represents the closing speed without the inertia device and curve D illustrates the closing speed of the circuit breaker controlled by the inertia device. Curve D shows that by use of this invention the speed of the moving parts of the circuit breaker is substantially educed (about 50%) just before the contacts engage and that the inertia device then returns a large part of the energy to the mechanism to assist in the final closing operation.

its? nte u er m c a sm li 'e d p etits mechanism end. e red e s ene g l ss s due to shock and vibration.

Te amou t o s eeeleretie may be varied by sue utin mass 9 r ter q letter t It? it mass m 9 th ime d rin a. steame a whi th inertia e e-r ta ds the ep m s eed at the me ha i m we the lift an a e b a in the P051 r I?" c c ii le itie v i i t e a t 4.39.-

He ifi ti ribe h inv nti n in e ments Withlth patent ta utes. t is to be netlet iea tha aridg ma e ant m difie t ees e 19-? mass in the st bmre d teils theme? Witewt depa t n f m th essentiel e res 9 th is: Yeiitipn.

I clai as e v nveeti n f f "espr fl es-1. mm h vin 2 s ies .Q e nected parts in during the -en le id s nebti mas a a ime 9 said mass to said arm and having its line of act 1} mo a e e r e me sei sa s and sa ce sth ct a d a t d man e by sai -vs'r t e aton men tens sale t6 s eat eas o e ene 9 th I evn? Pe -ts a a m d iermn d a n ssi a alesiel m v men sa ine tia membe t firs ie ax i f lesir eielietend th t9 e e i P said shaft urging said s haf;t in closing dir ion 3. A circuit interrupter comprising stationary m nt of said shar and movablecontact means, afseries of parts ineluding a shaft operable to close the i nterrupter, power operated means -for movi n said parts and said shaft, an arm on said shaft, unbalanced mass, a pivot for supporting said unbalanced .mass, a link conneotingsaid mass to said arm {or movement therewith having its line of action movable over .center, and said pivot -beingdisposed adjacent the path of movement of said arm so that said over center movement muses said mass to retard movement of' said -parts for .apredetermined time during a .c1osing..operation.

A. A circuit interrupt-er (having aseries of parts which are movedtogether during "movement .of the interrupter .to .closed position. an inertia m mber. (and an oveltrcenterilinkage connecting a rtia mb iins of said ar s e 9.11: H. fid

erati iig said inertia member; saidl k I part forming a toggle'n' ovablefov r 4 during. closingbperation so that the mass or said inertia member'is applied to said moving parts in a nannerto increase the effective mass of said moving parts at a predetermined time urin the closing movement to retard the pigs; ing movementof said parts.

A circuit interrupter comprising stationary and movable ,contact'rneans,operating 'mecha? nism therefor including 'a seriejs'of pai'ts'nvhi'c'h are moved togethert'o elffect closing movementbt said movable contact means, a pivoted inertia member, connecting means pivotally connecting said inertia member to a part of said operating mechanism for movement therewith at all times. said ,cbnnectingmeans and said part forming toggle movable over center to first cause Said inertia member to retard opening movement of said mechanism just before the 'ccntactmeans engage and then apply a force to assist said. 0p: erating mechanism during the latter portion of the closing movement.

.6. circuit interrupter having a series of parts which are moved together during m ovement'of the interrupter to closed position, apivoted inertia me'mberfia 1inkage connecting said inertia member to one of said parts for operating said inertia member, said linkage and said'partforming a toggle movable over center during a biosing operation to cause said inertia memberto absorb abortion of' the kinetic energy ofsaid moving parts at a predetermined time during he closing movementf and said linkage being'constructed and arranged to then restore a portion of the energy to said moving parts.

7. A circuit interrupter having a series of parts including a shaft rotatable toclose said inter ru'pter, anvarm o'n'said shaft, an unbalancedmass, .a pivot supportin said unbalanced mass, a linkage connecting said unbalanced mass tosa-id arm, said arm' being movable over center .rje'la tive tojsaid pivot at a predetermined time during' the closing operation to cause theinass'to retard closing movement of said parts andsaid shaft. 7.. 8. A circuit interrupterhaving a seriesof parts including a shaft operable to close said interruptjer, an 'arm on said shaft, an energy storing device comprising a masspivoted ona fixed pivot, a linkage connecting said'energy storing deviceito said arm for movement therewith at all times, said mass, said pivot and said linkage forming a toggle movable over center to cause said mass at a predetermined time during .a llfiising o eration to .absorb energy from said fpartstoIthereby retard closing movement .of said parts land then later during'ithe closing operation'freturn stored energy to .said parts to assist said parts iri'othe closing operation. ROSWELL c. VAN SICKLE.

l Q thi i et e UNITED STATES PATENTS Name Date Number H B d n' a e Lassen

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