US3665134A - Circuit breakers having radial magnetic field coil inserted into series circuit during the opening operation - Google Patents

Abstract

A fluid-blast circuit interrupter of the piston type has a movable operating cylinder carrying an orifice and a movable contact. The movable orifice structure has a movable probe, which connects into the series electrical circuit a movable radial magnetic field coil, which causes a rotation of the established arc around a conducting ring incorporated into the orifice structure. The combination of the rotating arc and the gas blast through both a side vent and an axially disposed orifice effects quick extinction of the established rotating arc.

Description

United States Patent Fischer 1151 3,665,134 1451 May 23,1972

1541 CIRCUIT BREAKERS HAVING RADIAL MAGNETIC FIELD COIL INSERTED INTO SERIES CIRCUIT DURING THE OPENING OPERATION [72] Inventor: William H. Fischer, Pittsburgh, Pa.

[73] Assignee: Westinghouse Electric Corporation, Pittsburgh, Pa.

[22]. Filed: Mar. 16, 1970 [21] Appl. No.: 19,629

Related US. Application Data I [62] Division of Ser. No. 576,707, Sept. 1, 1966, Pat. No.

521 US. 01. ....200/14s A, 200/150 0, 200/148 1 51 1111. c1. ..110111 33/70 58 Field 61 Search ..200/148 0, 148 F, 148 A, 150, I 200/1500, 148 B, 148 J, 148

[56] References Cited 1 UNITED STATES PATIENTS 3,257,532 6/1966 Lerch ..200/148 A 3,291,948 12/1966 TelfOl'd ..200/14s A 3,291,949- 12/196 Cronier ..200/150 3,379,848 4/1968 Colclaser, Jr. et ....200/148 13 3,390,240 6/ 1968 Circle et al ..200/ 148 .1 3,551,625 12/1970 Fischer ..200/148 FOREIGN PATENTS OR APPLICATIONS 662,215 7/1938 Germany ..200/148 A 1,190,079 4/1965 Germany... .....200/148 .1 1,206,056 12/1965 Germany ....200/148 A 1,142,201 l/l963 Germany ...200/148 A 575,854 3/ 1946 Great Britain ..200/148 C Primary ExaminerRobert S. Macon Att0mey-A. T. Stratton, Clement L. McHale and Willard R. Crout 57 ABSTRACT A fluid-blast circuit interrupter of the piston type has a movable operating cylinder carrying an orifice and a movable contact. The movable orifice structure has a movable probe, which connects into the series electrical circuit a movable radial magnetic field coil, which causes a rotation of the established are around a conducting ring incorporated into the orifice structure. The combination of the rotating arc and the gas blast through both a side vent and an axially disposed orifice effects quick extinction of the established rotating arc.

" 5 Claims, 8 Drawing Figures Patented May 23, 1972 2 Sheets-Sheet 1 FIG. 2.

. f l I mmam mxmwdom CIRCUIT BREAKERS HAVING RADIAL MAGNETIC FIELD COIL INSERTED INTO SERIES CIRCUIT DURING THE OPENING OPERATION This patent application is a division of my parent patent application filed Sept. 1, 1966, Ser. No. 576,707, which issued as US. Pat.-No. 3,551,625 entitled Circuit Breakers, and assigned to the-.assignee of the instant application.

This invention relates, generally to circuit breakers and, more particularly, to interrupters for extinguishing arcs in circuit breakers utilizing a pressurized fluid as an interrupting medium.

Prior interrupters for use with a pressurized interrupting medium such as, for example, sulfur hexafluoride (SF gas, have been of two general types, one, a cross-blast interrupter and, the other, an axial-flow interrupter. Previous cross-blast interrupters of the splitter type have the ability to interrupt high currents, but can be used only at relatively low voltages because of bridging insulation across the open contact members. Axial-flow interrupters have the ability to withstand rela tively high voltages.

An object of this invention is to provide a circuit interrupter having the advantages of the high interrupting capacity of a cross-blast interrupter together with the ability of an axialflow interrupter to withstand high voltage.

Another object of the invention is to utilize an arc splitter in an interrupter as a probe for connecting either a shunting resistor, or a magnetic driving coil, or both, in the circuit being interrupted.

A further object of the invention is to provide a multi-probe multi-orifice interrupter.

Still another object of the invention is to provide an interrupter having the effect of a plurality of nozzles for directing the flow of the interrupting medium.

A still further object of the invention is to provide for utilizing the interrupter as part of a magnetic pufier structure.

Another object of the invention is to provide for inserting a plurality of magnetic coils into the circuit being interrupted.

Other objects of the invention will be explained fully hereinafter or will be apparent to those skilled in the art.

In accordance with one embodiment of the invention, a circuit breaker is provided with an interrupter of the fluid-blast type. The interrupter is so constructed that the flow of interrupting fluid is directed across the arc drawn between contact members of the breaker and also axially along at least one of the contact members. The are is driven toward an arc splitter in the interrupting chamber and into a cross-blast opening for the chamber. The cross-blast and axial-flow of the fluid cooperate to extinguish the arc. A conductor or are horn on the arc splitter engaged by the arc is utilized to connect a shunting resistor, or a magnetic driving coil, or both, in the circuit being interrupted.

For a better understanding of the nature and objects of the invention, reference may be had to the following detailed description, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a view, in side elevation, of a three-phase circuit breaker embodying principal features of the invention;

FIG. 2 is a view, in section taken along the line II-Il of FIG. 1, showing one pole unit of the breaker, the contact members of the breaker being in the closed position;

FIG. 3 is a view, similar to FIG. 2, the contact members being in the open position;

FIG. 4 is a view, in section, of a modified-type of interrupter constructed in accordance with the invention, the contact members being closed;

FIG. 5 is a view of the interrupter of FIG. 4, the contact members being partly open;

FIG. 6 is a view, insection, of a combined pufi'er and interrupter embodying features of the invention;

FIG. 7 is a view, in section, of a modified interrupter of the type shown in FIG. 6; and,

FIG. 8 is a view, in section, of another modified interrupter.

Referring to the drawings and particularly to FIGS. 1, 2 and 3, the circuit breaker shown therein is of the dual pressure type having a low pressure tank 1 l and a high pressure tank 12 mounted on top of the tank 11. As shown, three pole units are mounted inside the one. tank 11. Each pole unit may be mounted in a separate tank if desired. The tank 11 is supported by feet 13 which rest upon beams 14, which, in turn, rest upon a suitable foundation 15. As shown most clearly in FIG. 1, the beams 14 also support a housing 16 containing asuitable operating mechanism and a compressor. The tank I 1 contains a suitable interrupting fluid such as, for example, sulfur hexafluoride (SF gas, at a relatively low pressure. The tank 12 also contains sulfur hexafluoride (SF gas at a relatively high pressure. The high pressure is maintained by the compressor, which draws gas from the low pressure tank 11 after an interrupting operation and returns it to the high pressure tank 12.

As shown most clearly in FIG. 2, each pole unit comprises a pair of terminal bushings 17, a relatively stationary contact member 18, a relatively movable contact member 19 and an interrupter 2 1, The bushings 17 are mounted upon collars 22 attached to the upper portion of the tank 11. The stationary contact member 18 and the interrupter 21 may be supported by one of the bushings 17. The movable contact member 19 may be pivotally attached to the inner end of the other bushing 17 as indicated by the reference numeral 20. The movable contact members for all three pole units may be operated by an operating shaft 23, which is connected to each one of the movable contact members by means of an insulating linkage 24. The shaft 23 may be rotated by means of the operating mechanism which may be of a type well known in the circuit breaker art.

The interrupter 21 comprises a body member 25 which is constructed to provide an interrupting chamber 26 on the inside of the body member with an arc splitter 27 disposed within the chamber 26. The body member 25 and the arc splitter 27 are preferably composed of an insulating material such as, for example, polytetrafluoroethylene, which is sold under the trade name Teflon".

The interrupting chamber 26 has an inlet opening 28, a cross-blast exhaust opening 29 and an axial-flow exhaust opening 31. The inlet opening 28 is connected to the high pressure tank 12 through a blast tube 32 and a blast valve 33. The valve 33 is opened, in conjunction with the opening of the breaker contact members to admit pressurized fluid, such as (SF gas, into the interrupting chamber 26 to extinguish the are 30 drawn between the contact members when they are separated.

As shown most clearly in FIG. 3, the interrupter is so constructed that the flow of the interrupting fluid is directed across the are 30 to drive it towards the arc splitter 27 into the cross-blast openings 29. As shown by the arrows in FIG. 3, part of the fluid also flows through the axial-flow exhaust opening 31 along the movable contact member 19. In this manner the cross-blast action and the axial-flow action cooperate to extinguish the arc. Such a scheme combines the advantages of the high interrupting capacity of a cross-blast interrupter together with the high voltage withstandability 0 an axial-flow interrupter.

In order to still further increase the interrupting capacity of the interrupter, a shunting resistor 35 is connected in parallelcircuit relation with a portion of the are by means of an arc horn or conducting means 36 on the inner end of the arc splitter 27. The conducting means 36 is connected to one terminal of the resistor 35 by a conductor 37. The other terminal of the resistor is connected to the stationary contact member 18. As shown, the resistor 35 may be mounted on the contact member 18 or it may be supported in any other suitable manner. Thus, the resistor 35 is connected in the circuit being interrupted. When the are 30 engages the conducting means 36 a portion of the arc current flows through the resistor 35.

The modified interrupter 21 shown in FIGS. 4 and 5 is generally similar to the interrupter shown in FIGS. 1, 2 and 3. The movable contact member 19 is of the reciprocating type. Also, an axial-flow exhaust opening 39 is provided around the fixed contact member 18. Thus, as shown by the arrows in FIG. 5, fluid flows through the exhaust openings 31' and 39 along both contact members 19 and 18. Since the contact members are separated from the solid insulating material of the interrupter by the high dielectric interrupting medium when in the open position, the voltage withstandability of the interrupter is increased.

As shown in FIG. 5, the fluid flow is directed into the interrupting chamber 26 to drive the arc 38 toward the arc splitter 27 and into the cross-blast exhaust openings 29'. The fluid flow is also directed through the exhaust openings 31 and 39 to assist in extinguishing the arc. The resistor 35' is connected in the circuit being interrupted ,by conducting means 36' and conductor 37' in the manner hereinbefore described.

In the modification of the invention shown in FIG. 6, a puffer mechanism and an interrupter are combined into one unit. The pufier comprises a relatively movable cylinder 41 and a relatively stationary piston 42 disposed inside the cylinder 41. A nozzle 43 is formed integrally with a cylinder head 44. The nozzle 43 is constructed to form an interrupting chamber 45 inside the nozzle having an axial-flow tapered exhaust opening 46 and a cross-blast opening 47 through the side wall of the nozzle 43. A throat opening 48 through the cylinder head 44 connects the interrupting chamber 45 with the area 49 inside the puffer cylinder 41. The cylinder 41 and the nozzle 43 are composed of a suitable insulating material, such as, for example, polytetrafluoroethylene. The piston 42 is also composed of a suitable insulating material.

A plurality of contact fingers 51 are pivotally mounted in the throat opening 48 which extends through the cylinder head 44. The fingers 51 are biased inwardly by a garter spring 52. When the breaker is closed, the contact fingers 51 engage a relatively stationary contact member 53 which extends through the nozzle opening 48. The continuous current carried by the breaker flows through the contact member 53, the contact fingers 51, and conducting strip 54 and continuous current collector 55 to a terminal member 56. The current collector 55 is biased outwardly by a spring 57. The terminal member 56 may be connected to one terminal of the circuit breaker Ll. Likewise, the contact member 53 may be connected to the other terminal L2 of the breaker, thereby completing a circuit through one pole unit of the breaker.

When the breaker is opened, the cylinder head 44 is moved towards the piston 42, thereby compressing the interrupting fluid within the cylinder and forcing it through the throat opening 48 into the interrupting chamber 45. The cylinder 41 may be actuated by pull rods 58 which are attached to pins 59 on the outside of the cylinder wall and are driven by a suitable operating mechanism (not shown).

When the contact fingers 51 are separated from the contact member 53, an are 61 is drawn within the interrupting chamber 45. The flow of fluid through the throat opening 48 drives the arc 61 toward an arc splitter 62 disposed within the chamber 45. As shown, the arc is driven into the cross-blast exhaust opening 47. Part of the fluid also flows through the nozzle opening 46 along the contact member 53. Thus, the cross-blast action and the axial-flow action cooperate to extinguish the arc.

As explained in the copending application Ser. No. 576,739, filed Sept. 1, 1966, now U.S. Pat. No. 3,524,959 issued Aug. 18, 1970 to R. E. Frink and assigned to the Westinghouse Electric Corporation, the force produced by two spaced magnetic coils, which are energized by the current being interrupted may be utilized to assist in operating the puffer mechanism to drive the interrupting fluid into the interrupting chamber. Accordingly, one coil 63 is provided in the cylinder head 44 and another coil 64 is provided in the piston 42. One terminal of the coil 63 is connected to a conducting member 65 on the inner end of the arc splitter 62 by a conductor 66. The other terminal of the coil 63 is connected to one terminal of the coil 64 through a conducting strip 67, a current collector 68 and a conducting member 69. The other terminal of the coil 64 is connected to the terminal member 56 by a conducting member 71. Thus, when the are 61 engages the conducting means 65 on the arc splitter 62, the magnetic driving coils 63 and 64 are connected to be energized by are current.

The modified-type interrupter shown in FIG. 7 is similar to the one shown in FIG. 6 with the exception that an additional arc splitter 72 is provided in the interrupter. A conducting member or are horn 73 is provided on the inner end of the splitter 72. The conducting member 73 may be connected to a shunting resistor R by means of a conductor 74. Thus, the shunting resistor and the magnetic driving coils, previously described, may be connected in the circuit being interrupted.

It becomes more difiicult to insert magnetic coils into a circuit as the number of turns (i.e. inductance) increases. It also becomes more difiicult as the amount of current being interrupted increases. The present structure can be used with large inductance coils and large currents. It has this ability since essentially a separate interrupter is used to insert the coils into the circuit. Also, a relatively long are can be drawn and fresh un-ionized gas is utilized to extinguish the arc.

FIG. 8 shows an interrupter in which an annular vent 75 is provided in the interrupter nozzle 76. This has the efiect of a nozzle within a nozzle. Two nozzles are shown in FIG. 8. Additional nozzles could be provided by providing additional annular vents, similar to the vent 75. A circular arcing ring 77 is provided at the entrance to the annular vent 75 on an arc splitter 78. The ring 77 connected to one terminal of a radial magnetic field coil 79 by a conductor 81. The coil 79 is disposed in a body member 82 in which the contact fingers 51 are mounted. Since this is a conducting member, the other terminal of the coil 79 may be connected to the body member as at 83. Thus, the coil 79 is energized by are current to produce a magnetic field which spins the arc around the circular arc ring 77. This reduces the erosion on the contact members and the insulating nozzle 76. The spinning also enhances interruption.

When the contact member 53' is separated from the contact fingers 51 and the interrupting fluid flows through the throat opening 48', the arc 61 is driven toward the arcing ring 77 and into the annular vent 75. Fluid also flows through the nozzle opening 46 along the contact member 53'. As previously explained, the annular vent 75 functions as an additional nozzle which cooperates with the nozzle opening 46 in extinguishing the arc. The spinning action produced by the radial magnetic field coil 79 also assists in extinguishing the arc.

The above-described interrupters may be utilized in a number of different ways from low power, low voltage to high power, high voltage circuit breakers. If desired, several interrupters may be utilized in series for higher voltage applications. Furthermore, other interrupting media such as air, oil, or (CO) may be utilized in place of (SP if desired. As previously explained, the present structures combine the advantages of cross-blast interrupters and axial-flow interrupters.

Certain features of the instant application are set forth and claimed in U.S. patent applications filed Jan. 26, I965, Ser. No. 428,077,, now U.S. Pat. 3,379,848 issued April 23, 1968 to Robert G. Colclaser, Jr. and Frank I... Reese, and filed Sept. 18, 1964, Ser. No. 397,512, now U.S. Pat. 3,291,949, issued Dec. 13, 1966, to Charles F. Cromer, and assigned to the assignee of the instant application.

Since numerous changes may be made in the abovedescribed construction and different embodiments of the invention may be made without departing from the spirit and scope thereof, it is intended that all subject matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim as my invention:

1. In a circuit interrupter, in combination, an interrupting chamber having an inlet throat and a tapered noale exhaust opening, relatively stationary contact members disposed in the throat a relatively movable contact member extending through the nozzle into the throat to engage the stationary contact members, an annular vent for the chamber, a circular arc splitter at the entrance to the vent, an arcing ring on the arc splitter, said movable contact member being separable from the stationary contact member to draw an arc within the chamber, means for directing a flow of pressurized fluid through the throat across the arc to drive it toward the splitter and into the vent, part of said fluid also flowing through the tapered nozzle exhaust opening along the movable contact member, a magnetic coil surrounding the stationary contact members, and said coil being connected to the arcing ring to be energized by arc current to establish a magnetic field for spinning the are around the ring.

2. A circuit interrupter of the fluid-blast type including a relatively movable piston member and an operating cylinder member, a movable contact and a radial magnetic field coil carried by one of said members, said one member in addition carrying an arcing ring connected to said radial magnetic field coil, a relatively stationary contact cooperable with said movable contact to establish an arc, means for transferring the initially established arc to said arcing ring to insert thereby the radial magnetic field coil serially into the electrical circuit to generate a radial magnetic field for rotation of the are about said arcing ring, an orifice structure carried by said one member to force fluid under pressure against the rotating arc to effect its extinction.

3. The combination of claim 2, wherein the said one member is the movable operating cylinder.

4. The combination of claim 3, wherein the other member is a stationary piston.

5. The combination of claim 2, wherein the said one member has a nozzle shaped movable contact at the orifice structure.

Claims (5)

1. In a circuit interrupter, in combination, an interrupting chamber having an inlet throat and a tapered nozzle exhaust opening, relatively stationary contact members disposed in the throat a relatively movable contact member extending through the nozzle into the throat to engage the stationary contact members, an annular vent for the chamber, a circular arc splitter at the entrance to the vent, an arcing ring on the arc splitter, said movable contact member being separable from the stationary contact member to draw an arc within the chamber, means for directing a flow of pressurized fluid through the throat across the arc to drive it toward the splitter and into the vent, part of said fluid also flowing through the tapered nozzle exhaust opening along the movable contact member, a magnetic coil surrounding the stationary contact members, and said coil being connected to the arcing ring to be energized by arc current to establish a magnetic field for spinning the arc around the ring.

2. A circuit interrupter of the fluid-blast type including a relatively movable piston member and an operating cylinder member, a movable contact and a radial magnetic field coil carried by one of said members, said one member in addition carrying an arcing ring connected to said radial magnetic field coil, a relatively stationary contact cooperable with said movable contact to establish an arc, means for transferring the initially established arc to said arcing ring to insert thereby the radial magnetic field coil serially into the electrical circuit to generate a radial magnetic field for rotation of the arc about said arcing ring, an orifice structure carried by said one member to force fluid under pressure against the rotating arc to effect its extinction.

3. The combination of claim 2, wherein the said one member is the movable operating cylinder.

4. The combination of claim 3, wherein the other member is a stationary piston.

5. The combination of claim 2, wherein the said one member has a nozzle shaped movable contact at the orifice structure .

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