US2125525A - Electric circuit breaker - Google Patents

Description

Aug.2,193s. H, THOMMEN' 2,125,525

ELECTRIC CIRCUIT BREAKER Filed May 1, 1957 '3 SheeS-Shee l ff@ ff I.e-fml! H.-THOMMEN 2,125,525

ELECTRIC CIRCUIT BREAKER Filed May l, 1957 3 Sheets-Sheet 2 Auw. Z, 1938 y Aug. 2, 1938.

HQTHOMMHEN ELECTRIC lCIRCUIT BREAKER i Filed May 1, 1957 UElllll 3 Sheets-Sheet 3 Patented Aug. 2, 1938 Partienv orricr ELECTRIC CIRCUIT BREAKEB.

Hans Thommen, Baden, Switzerland, assigner to Aktiengesellschaft Brown Bovcri d; Cie, Baden, Switzerland, a joint-stock company of Switzerland Application May 1, '1931, serial No. 140,078

In Germany .my 13,1935

16 Claims.

This invention relates in general to improvements in electric circuit breakers, and more particularly to circuit breakers of the fluid blast type in which the functions of interrupting the flow of current in a circuit. and of thereafter maintaining the circuit opened are performed by separate elements.,

In the operation of circuit breakers of the fluid blast type, the current interruption takes place under themost advantageous conditions when the arcing contacts are rapidly separated to 'a distance permitting the flow therebetween oi a blast of fluid of maximum velocity from the available source of iiuid under pressure. The contacts are thus separated only for such distance that an are would be reestablished therebetween upon interruption of the fluid blast, and it is thus necessary to open the circuit by means of 4a pair of4 disconnecting contacts while the fiuid blast is being maintained between the arcing contacts.` Such procedure results in the con sumption of an amount of fluid which is considerably greater than the amount required for actually interrupting the arc.

Such consumption may be materially reduced by providing the arcing chamber outlet with a valve for stopping the flow of iiuid thereinto and for confining fluid under pressure within the chamber after interruption of the arc. As is well known, the dielectric strength of atmospherlc air and of a number of other fluids utilized in fluid blast circuit breakers increases with the pressure of the uid at least up to a predetermined value of pressure. By suitably selecting the pressure of the iiuid and the distance separating the arcing contacts, the breakdown voltage of the space between the contacts may be maintained at such a high value that the arc will not be reestablished between the contacts, and the opening of the circuit by the disconnecting contacts may then take place at such time as may be found desirable lor convenient. If a plurality of pairs of arcing contacts sep- "arately operated by fluid under. pressure are utilized in series, the several contact actuating means should receive iiuid'under pressure simultaneously from the arcing chamber when the pressure within such chamber has reached a predetermined valueto insure simultaneous opening of all contacts when the pressure within the arcing chamber is suiiicient to interrupt the are drawn between the contacts.

It is, therefore, one of the objects of the present invention to provide a circuit breaker oi the fluid blast type in which arcing contacts and (Cl. 20o- 148) disconnecting contacts may be sequentially opened with a suitable time interval between such opening operations.

Another object of the present invention is to provide a circuit breaker of the fluid blast type in which arcing contacts are separated by iluid under pressure conilned within the arc chamber itr interruption of the arc between the conac s.

Another object of the present invention is to provide a`circuit breaker of the fluid blast type in which a plurality of pairsv of arcing contacts are caused to open simultaneously only when the pressure within the arcing chamber exceeds a predetermined value.

Objects and advantages other than those above set forth will beapparent from the following description when read in connection with the accompanying drawings, in which:

Fig. 1 is a view in elevation of a circuit breaker embodying the present invention and comprising a plurality of pairs of arcing contacts and a plurality of pairs of disconnecting contacts;

Fig. 2 is a horizontal cross sectional view of the arcing chamber of the embodiment illustrated in Fig. 1 taken on plane II-II in Fig. 1 and in Fig. 3;

Fig. 3 is a vertical cross sectional view of a portion of the arcing chamber of the embodiment illustrated in Figs. 1 and 2 taken on two planes III- Ill joining at the axis of the chamber;

Fig. 4 is a vertical cross sectional view of the Iarcing chamber of a modified embodiment of the nvention utilizing only one pair of arcing conacts;

Fig. 5 is a vertical cross sectional viewy o1' a.- modified form of the arcing chamber outlet valve illustrated in Fig. 4;

Fig. 6 is a vertical cross sectional view of another modined form of the arcing chamber cutlet valve illustrated in Fig. 4; and

Fig. '7 ls a vertical sectional view of a part of the circuit breaker shown in Fig. 1.

Referring more particularly to the drawings by characters ci reference, Fig. 1 illustrates a circuit breaker comprising a reservoir I'I lconstituting a source of supply of fluid under pressure. Such fluid is assumed herein to be compressed air supplied to the reservoir by a suitable compressor (not shown) to maintain the pressure within the reservoir at a substantially constant value, but

it will be understood that other fluids such as nitrogen or helium, may also be utilized. Reservoir Il is provided with suitable means for sup-.- porting the circuit breaker en ground or on a lators I2, Il and l4of dimensions which are-de. termincd by the voltage of the circuit in which the circuit breaker is to beinserted. Insulators I2 and I4 arenxed and-support one terminal Il and the nxed disconnecting contacts I1 of the circuit breaker. Insulator Il carrying the movable disconnectingcontacts Il of the circuit,V

breaker is pivotally mounted on reservoir Il and may be rotated about a vertical axis of a suitable' compressed air motor II.

Insulator I4Iis hollow and forms 4a 4part of the arcing chamber of the circuit breaker. such chamber also comprising a pair of insulators 2i, 22 joined by a double walled metallic member 23. Member 23 dennes a plurality ofpassages 24, 2l, and cooperates with contacts 2l to form a cham-f ber or a plurality of chambers 2l. .The walls of member 23 may bemade oir several segmental portions to permit introduction within the chamber 20. of certain elements of the circuit breaker.l

issuing from the chamber through outlets 25'.,

Valve 21 also controls the admission of compressed air to motor I3. 'Ihe valve maybe of any suitable type known in the art,but ispreferably of the type disclosed and claimed in capending application Serial No'. 60,362 of Arnold Haller and Hans Thommen, tiled February 21, 1938.

As illustrated in Figs. 3 and 7, each of the insulators 2| and` 22 contains a pairof cooperating arcing contacts 23,23. Contacts 2l rare fixed contacts, the upper contact 2l being rigidly mounted on terminal 24 and the lower contacty 2l being rigidly mounted ona perforated diaphragm Il inserted between insulators I4 and 2| and connected with one of contacts l1 through an' electrostatic shield 3|. Contacts V23 are hollow movable contacts penetrating within-member 23 in sliding engagement therewith. Contacts 28 and 23 may. be made of any suitable conductive material and may be provided with renewable arcing tips oi' dimcultly fusible conductive material if desired. When 'the contacts 2l, 23 are.

closed, such contacts .divide the arcing chamber into two portions, an inlet portion and an outlet portion. 'I'he inlet portion 'of the chamber comprises the space extending from the inlet valve 21 4through the insulator I4, the space between -the arcing contacts 2l. 2l and insulators 2l and 22, and passages 24 in member-23. The outlet portion oi' the 'arcing chamber consists ol the space 20 extending lthrough contacts 2l and member to the outlets 2l. Compressed air is admitted to the outlet portion from the inlet portionlthrough contacts 23 upon separation yof the arcing contacts.

A plurality of contactseparating means op'- erable -by air under pressure are severally associated with the diiferent pairs oi' contacts 23, 2l. EachI such means comprises an annularpiston 32 `mounted on the associated contact 2l and arf ranged within a cylinder 33 mounted on or forming parto! member 23. Each piston moves the ,associated contact 2l against the action of a spring 34 tending to maintain the associated pair of 'contacts closed. During such movement of contactsl 23, the electrical connection between such 4contacts is, maintained by member 23 and yby a plurality of sliding contacts 38 each urged by springs against the associated contact 23 and against a portion-of member 23. fPistons 32'arc actuated by compressed air introduced into the inlet portion of the arcing chamber of the circuit breaker.

When compressed air is introduced into the inlet portion, thepressure therein can only rise graduallydue to the throttling action of the small valve 21. If cylinders 33 were in direct communi- Acation with the inlet portion, the pressure within the cylinders would also rise gradually. Each contact 29'would then move when the pressure on the associated piston 32 became sufficient to overcome the action of'the associated spring 34 and the friction of the contact against the fixed members adjacent thereto.` The diil'erent moving contacts would therefore not open simultaneously. and additional means should be provided for insuring simultaneous operation of the different contact separating means. For obtaining such result, compressed air is suppliedl from the inlet chamber portion to cylinders 33 through channels 31 within the inner wall of member 23 and through a plurality of additional'valves 33. Valves 38 tend to be opened by the pressure of the compressed air within the inlet portion and are normally maintained on the seats thereof by springs 39. The valves' are thus made responsive to increase of the pressure within the inlet portion for supplying compressed air from such portion simultaneously to all the contactseparating -m'eans at such pressure that all contacts 29 may be actuated simultaneously; The compressed air.

and which are preferably distinct from such contact separating means. For this purpose each cylinder 33 cooperates with another cylinder 43 coaxial-therewith to form an annular space receiving an annular piston 44. Each piston 44 is provided with a cylindrical'extension.forming a slide valve 46 cooperating with a partition 41 ar- A ranged transversely to separate chambers 20, for

controlling outlets 25. Each piston 44 is actuated by compressed air introduced between the associated cylinders 33 and 43 from within cylinder 33 through ports 48 in response to th'e operation. of the associated piston 32. then urges the associated valve 46 toward partition 41 againstthe action of a spring 49 assoy elated therewith. The air confined within the space containing springs 43 may be allowed to escape through ports 5i in cylinders 43. In providing the above operation, cylinders 33 and 43 and pistons 44 constitute compressed air motors arranged to receive air under pressure in response to the operationof the associated contact sepa- Yrating means'- for actuatingthe associated valves only. upon separation of the arcing contacts to a predetermined distance.'

Assuming the circuit breaker to be in the closed position shown in Figs. l, 3 land 7, if it is desired to cause the circuit breaker to open, valve 21 is opened eithermanually or in any other manner. Compressedair is thereby admitted through Piston 44 i an air blast capable of cooling and deionizing the shown by the arrows in Fig. 3.

the inlet valve 21 into the inlet portion of the arcing chamber. The pressure of the air within the inlet portion rises at a rate depending upon the volume of the chamber and on the size of the opening of valve 21, and such pressure nally becomes suicient to causevalve 38 to open. Ccmpressed airis then admitted from the inlet portion into cylinder 33'through valves 38 and passages 31 thereby causing pistons 32 to be actuated simultaneously to separate the associated' contacts 2S from the cooperating contacts 28. Upon such separation of a pair of contacts, an arc is drawn -therebetween and simultaneously a blast of compressed air is projected between the contacts from the inlet portion to the outlet por` tion, such blast escaping from the arclng chamber through outlets 25 andmufer 4i to the ambient atmosphere, following the paths as The arc is forced to leave the shortest path between the contacts by the air blast and the point of attachment thereof to contact 29 is moved to diierent points on the inner surface of the movable contact more and more remote from the xed contact. The stroke and inner diameter of each contact 29 are so chosen as to allow the establishment of arc path to a sufficient extent to prevent reestablishment of the arc after passage of the arc current through the value zero when the circuit breaker is utilized in an alternating current circuit. After passage of piston 32 over port 48, compressed air is admitted behind piston 44 and such piston urges the associated valve 46 into contact with partition 41. Each valve 46 thus functions responsive to the operation of the associated contact separating means for closing outlets 25 thereby confining compressed air within the arcing chamber after interruption of the arc. The reestablishment of the arc between contacts 28 and 29 is thus prevented as eiectlvely as if the air blast were maintained between such contacts, with the advantageous result that'iurther consumption of air is substantially prevented. The operation of valves 46 takes place with a time delay depending upon the size and number of ports I. Upon closure of valves 46 the air pressure within member 23 becomes equal on both sides of pistons 32 and springs 34 return contacts 2.9 to

the closed position shown'.

Simultaneously with the admission of air to the arcing chamber of the circuit breaker, air is admitted by valve 21 to compressed air motor I9. Such motor causes insulator I3 to rotate and to separate contacts I1 and I8. 'I'he speed of operation of contacts 29, of valves 46 and of motor I9 must be so related that contacts I8 begin to open only after interruption of the arc drawn in the `arcing chamber and that such contactsl reach substantially the end of the travel thereof before reclosure of contacts 23. If valve 21 ,is of the type disclosed in the above cited application, completion of the operation of motor I9 causes the valve to reclose. The air confined Within the arcing chamber maythen leak past the cooperating surfaces of contacts 28 and 29 and between valve 46 and partition 41 to the atmosphere. When the air pressure within the arcing chamber outlet portion decreases below a predetermined value, springs 43 return valves 46 to the position shown. I'he exhaust of air from the arcing chamber may be accelerated by providing valve 21 with a passage placing the arcing chamber in communication with the atmosphere when valve 21 is closed. Contacts 29 thus being returned to the closed position shown on the drawings. the circuit breaker may be reclosed by returning contacts I8 to the position I shown by means of motor I9.

The embodiment partially illustrated in Fig; 4 utilizes reservoir I I,valve 21 and an arcing chamber comprising insulator I4 and a single other insulator 52 mounted thereon. Insulator 52 supports a single xed annular contact 53 which is made at least partially resilient to insure the satisfactory conductive engagement thereof with a single cylindrical contact 54 coaxial with insulator 52 and movable in the longitudinal direction thereof. Contact 53 is maintained in position by a terminal member 56 bolted to a clamp 51 mounted on the upper portion of insulator 52. Contact 54 is provided with suitable contact separating means such as a piston 58 mounted thereon and movable in a cylinder 59 arranged within insulator 52. The cylinder is mounted on a perforated diaphragm 6I arranged between in" sulators I4 and 52.- Piston 58 is provided with a piston rod 62 and is urged upward by a spring 65. The electrical connection between terminal 56 and the contact I1 mounted on insulator I4 is eiiected through contact 53, contact 54, piston 58, piston .rod 62, one or more sliding contacts 63, cylinder 59 and diaphragm 6i. Cylinder 59 is adapted to receive air under pressure from the arcing chamber inlet portion through ports 64. The arcing chamber outlet portion consists of contact 53 and of terminal 56, and the latter is provided with an interrupted annular outlet 66 which may be closed by a sliding valve 61. Valve 61 is actuated by a piston 68 within a cylinder 69 supported by or forming part of terminal 56. Air under pressure may be admitted on the upper side of piston 68 from cylinder 59'througha pipe 1I of suitable insulating material. A spring 12 tends to maintain valve 61 in the open position thereof.

'I'he operation of the present embodiment differs vonly in detail from the operation of the embodiment illustrated in Fig. 1. Upon operation of valve 21, air ls admitted within insulators i4 and 52 and such air is admitted on the upper side of piston 58 through ports 64. Piston 58 is then urged downward against the action of spring 65 and causes separation of contacts 53 and 54. An arc is drawn between such. contacts and is interrupted by the blast of air passing between the contacts and escaping from the arcing charnber through outlet 66. After passagel of piston 58 over the inlet of pipe 1I, air under pressure is admitted from cylinder 59 into pipe 1I to the upper side of piston 68. Piston 68 moves valve 61 downward against the action of spring 12 to close outlet 66. Contact 64 remains open and valve 61 remains closed until subsequent closure of valve 21. Upon such closure of valve 21, the air conned within the arcing chamber escapes by leakage past valve 61 or by means of a discharge passage controlled by valve 21. Spring 12 then returns valve 61 to the open position shown and spring 65 returns contact 54 to the closed position shown.

The embodiment illustrated in Fig. 5 utilizes an outlet valve actuated by a compressed air motor connected with the arcing chamber outlet portion. Llerminall 56 extends only up to outlet 66 and supports the motor cylinder 1 3" containing a differential piston 14, which is urged upward toward the position shown by a spring 16. Plston 14 is provided with an extension 11 protruding from cylinder 13 and cooperating with contact 63 and with terminal 56 to form the arcing chamber outlet portion.` Extension 11 also forms a valve operable to close outlet upon down- -ward movement of piston 14. Ports. 1l and 1l are provided for placing the upper face .of piston 14 in communication with the arcing chamber outlet portion whereby the piston is rendered responsive to the admission of compressed air into suchoutlet portion upon separation of contacts 53 and 54 for actuating valve 11. It will be understood that such operation of piston 14 is possible for the reason that the air pressure is applied to the entire upper face of piston 14 and that such pressure may thus overcome the pressure exerted on the lower face of extension 11. which is of smaller diameterfthan piston 14, in addition to the effect of spring 1B. Valve 11 remains closed as long as pressure is maintained in the arcing chamber outlet portion. When such pressure is released by leakage about valve 11 or by the action oi the inlet valve of the circuit breaker, spring 1B returns valve 11 to the position shown.

In the embodiment partially illustrated in Fig. 6, a cylindrical outlet valve 8l is arranged about terminal I6 below outlet 66 for controlling such outlet. A` cylinder 82 is mounted on valve 8i' and is connected therewith through a plurality oi supports 03. Cylinder I2 is slidably mounted on a piston 04 forming part of terminal 56. The space within cylinder 82 is placed ln communication with the arcing chamber outlet portion tion as long as pressure -is ,maintained within the arcing chamber outlet portion and the valve is returned to tlie position shown by spring 8l upon release of the pressure'within such cham# ber portion.

Although buta few embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

It is claimed and desired to secure by Letters Patent: l

1. An, electric circuit breaker comprising a source of supply of fluid under pressure, an arcing chamber having an outlet, a pair of cooperating contacts arranged in said chamber, means cp'erable by fluid under pressure for separating said contacts, means for controlling the admission of fluid from said source into said chamber and to said 'contact separating means to cause' separation of said contacts and interruption of the arc drawn therebetween, and means distinct from said contact separating means and responsive tb the operation of said contact separating means for closing said outlet and maintaining fluid under pressure in said chamber.

2. An electric circuit breaker comprising a source of supply of fluid under pressure, an arcing chamber having an outlet, a pair of cooperating contacts arranged in said chamber, means operable by fluid under pressure for sep arating said contacts, means for controlling' the admission of lfluid from said sou-ree' into said chamber and to said contact separating means to cause separation of said contacts and interruption of the arc drawn therebetween, a valve for controlling said outlet, and a fluid actuated motor arranged to receive fluid under pressure in response to the movement of said contact separating means for actuating said valve.

3. An electric circuit breaker comprising a source of supply oi.' fluid under pressure, an arcing chamber having an outlet, a pair of cooperating contacts arranged in said chamber. means operable by fluid under pressure for separating said contacts, means for controlling the admission of fluid from said source into said chamber `and to said contact separating means pressure at said contacts after separation thereof, a cylinder arranged to receivefluid under pressure in response to the operation of said contact separatingvmeans, and a piston within said cylinder for actuating said valve.

4. An electric circuit breaker comprising a source of supply of fluid under pressure, an arcing chamber having an outlet, a pair of cooperating contacts arranged in said chamber, means operable by fluid under pressure for separating said contacts, means forcontrolling the admission of fluid from said source into said chamber and to said contact separating means to cause separation of said contacts and interruption of the arc drawn therebetween, a valve for controlling said outlet, a cylinder mounted on said valve and arranged to receive fluid under pressure in response to the operation of said contact separating means, and a piston arranged within said cylinder and ilxedly mounted on said chamber.

5., An electric circuit breaker comprising a source of supply of fluid under pressure. an arcing chamber having an inlet and an outlet, a pair of cooperating contacts arranged to divide said chamber into an inlet portion and an outlet portion, means for separating said contacts. means for controlling the admission of fluid from said source into said inlet portion, a valve for controlling said outlet, and means responsive to the admission of fluid under pressure into said outlet portion upon separation of said contacts for actuating said valve.

6. An electric circuit breaker comprising a source of' supply of fluid under pressure, an arcing chamber having an inlet and an outlet, a pair of cooperating contacts arranged to divide said chamber into an inlet portion and an outlet portion, means for separating said contacts, means for controlling the admission of fluid from said source into said inlet portion, a valve for controlling said outlet, and a fluid pressure motor con-4 nected with said outlet portion for actuating said valve to maintain fluid under pressure after separation of said contacts. y

. 7. An electric circuit breaker comprising a source of supply of fluid under pressure, an arcing chamber having an outlet, a pair of cooper ating contacts arranged in said chamber, means operable by fluid under pressure for separating said contacts, means for controlling the admission of fluid fronrsaid source into said chamber and to said contact separating means to cause separation of saidcontacts and interruption of the arc drawn therebetween, a valve for controlling said outlet, and means responsive to-sepa ration of said contacts to a predetermined distance for actuating said valve.

8. An electric circuit breaker comprising a source of supply of fluid under pressure, an arc-- ing chamber having an inlet and an outlet, a pair of cooperating contacts arranged to divide said chamber into an inlet portion and an outlet portion, means for separating said contacts, means for controlling the admission of iuidfrom said source into said inlet portion, a valve for controlling said outlet, means responsive to increase of the pressure within said outlet portion above a predetermined value for closing said valve, and meansresponsive to decrease of the pressure within said outlet portion below said predetermined value for opening said valve.

9. An electric circuit breaker comprising a source of supply of fluid under pressure, an arcing chamber having an inlet and an outlet, a plurality of pairs of cooperating contacts arranged to divide said chamber into an inlet portion and an outlet portion, a plurality of contact separating means operable by iluid under pressure severally associated with said pairs of contacts, means for controlling the admission of. iluid from said source into said inlet portion and to said contact separating means, means for insuring simultaneous operation of said contact separating means, valve means for controlling said outlet, and means responsive to the operation of said contact separating means for actuating said valve means.

10. An electric circuit breaker comprising a source of supply of iluid under pressure, an arcing chamber having an inlet and an outlet, a plurality of pairs of cooperating contacts arranged to divide said chamber into an inlet portion and an outlet portion, a plurality of contact separating means operable by uid under pressure severally associated with said pairs of contacts, means for controlling the admission of iluid from said source into said inlet portion, means responsive to increase of the pressure within said inlet portion above a predetermined value for supplying fluid from said inlet portion simultaneously to all said contact separating means. valve means for controlling said outlet, and means responsive to the operation of said contact separating means for actuating said valve means.

11. An electric circuit breaker comprising al associated with said pairs of contacts. means forv controlling the admission o! fluid from said source into said inlet portion, and means responsive to increase of the pressure within said inlet portion above a predetermined value for supplying fluid from said inlet portion simultaneously to all said Acontact separating means.

12. An electric circuit breaker comprising a source of supply of fluid under pressure, an arcing chamber having an outlet, a pair of cooperating contacts arranged in said chamber, means for separating said contacts, means for controlling the admission of fluid from said source into said chamber for producing a fluid blast across said contacts for extinguishing an arc drawn therebetween upon separation thereof, and means for thereafter closing said outlet to conne fluid under pressure in said chamber.

13. An electric circuit breaker comprising a source of supply of fluid under pressure, an arcing chamber having an outlet, a pair of cooperating contacts arranged in said chamber, means for separating said contacts, means for controlling l the admission of fluid from said source into said chamber for interrupting the arc drawn between said contacts upon separation thereof by a blast of fluid issuing from said chamber through said outlet, and means responsive to the operation of said contact separating means for closing said,

outlet.

14. An electric circuit breaker comprising a source of supply of iluid under pressure, an arcing chamber having an outlet, a pair of cooperating contacts arranged in said chamber, means operable by iluid under pressure for separating said contacts, means for controlling the admission of iiuid .from said source into said chamber and to said contact separating means to cause separation of said contacts and interruption of the arc drawn therebetween, and means responsive to the operation of said contact separating means for closing said outlet.

15. An electric circuit breaker comprising an arcing chamber having an outlet, a pair of co- .'operating contacts arranged in said chamber,

means for separating said contacts, means for producing a uid blast across said contacts for extinguishing an arc drawn therebetween upon separation thereof, and means for thereafter closing said outlet to conne iluid under pressure in said chamber.

16. An electric circuit breaker comprising an .arcing chamber having an outlet, a pair of cooperating contacts arranged in said chamber, means for separating said contacts, auxiliary contacts in series with said contacts, means for producing a fluid blast across said rst said contacts for extinguishing an arc drawn therebetween upon separation thereof, means for thereafter closing said outlet to coniine iluid under pressure in said chamber, and means for thereafter separating said auxiliary contacts.

HANS THOMMEN.

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