US3551625A - Circuit breakers - Google Patents

Description

United States Patent Inventor William II. Fischer Penn Hills, Pa. Appl. No. 576,707 Filed Sept. 1, 1966 Patented Dec. 29, 1970 Assignee Westinghouse Electric Corporation Pittsburgh, Pa. a corporation of Pennsylvania CIRCUIT BREAKERS 12 Claims, 8 Drawing Figs.

US. Cl 200/148, 200/ 1 47 Int. Cl ..I-I01h 33/91 Field of Search 200/148. 1,

1506,148,148A,148.3,149,l47;335/201,l4, 15,l6,18,l9,149,186,l95;307/136;317/152, 75,11

[56] References Cited UNITED STATES PATENTS 3.071.670 1/1963 Yeckley et a1. 200/l48(.1) 3,178,544 4/l965 Mayer 200/147 3,238,340 3/1966 Lerch 200/148(.l) FOREIGN PATENTS 1,142,201 1/1963 Germany 200/148(A) 1,206,056 12/1965 Germany... 200/147 107,686 6/1943 Sweden ZOO/148(3) Primary Examiner- Robert K. Schaefer Assistant E.raminerRobert A. Vanderhye Attorneys-A. T. Stratton, C. L. McI-lale and W. R. Crout ABSTRACT: An improved fluid-blast circuit interrupter is provided having accelerating coil means electrically switched into the circuit during interruption so as to aid by magnetic attraction movement of a movable piston means. A movable probe means. connected to a pair of accelerating coils, has the are transferred thereto by a blast of fluid generated by the piston means. A movable orifice structure supporting the movable probe means may be utilized, and one of the main contacts may be apertured to facilitate arc transfer.

CIRCUIT BREAKERS CIRCUIT BREAKERS 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 (H,) 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 relatively high voltages. g

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 axial flow 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 multiprobe, multiorifice interrupter.

Still another-object of the invention is to provide an interrupter having the effect of a plurality ofno zzles 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 puffer 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 interruptingfluid 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. I is a view, in side elevation, of a three-phase circuit breaker embodying principal features ofthe invention;

FIG. 2 is a view, in section taken along the line IIII 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, ofa modified type ofinterrupter 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, in section, ofa combined puffer and interrupter embodying features of the invention;

FIG. 7 is a view, in section ofa 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 II and a high pressure tank I2 mounted on top of the tank I I. As shown, three pole units are mounted inside the one tank II. Each pole unit may be mounted in a separate tank if desired. The tank II is supported by feet I3 which rest upon beams I4, which, in turn, rest upon a suitable'foundation 15. As shown most clearlyin FIG. 1, the beams 14 also support a housing 16 containing a suitable operating mechanism and a compressor. The tank I] 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 I9 and an interrupter 21. The bushings 17 are mounted upon collars 22 attached to the upper portion of the tank II. 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. I

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 arc 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 I9. 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 of 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 arc 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 arc 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 I9 is ofthe reciprocating type. Also, an axial flow exhaust opening 39 is provided around the fixed Contact member I8. Thus, as shown by the arrows in FIG. 5, fluid flows through the exhaust openings 31 and 39 along both contact members 19' and I8. 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 are 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 puffer 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 sidewall 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 L1. 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 members 53, an are 61 is drawn within the interrupting chamber 45. The flow of fluid through the throat opening 48 drives the are 61 toward an arc splitter 62 disposed within the I 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 Pat. No. 3,524,959 by 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 ofthe coil 63 is connected to one terminal ofthe 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 are splitter 62, the magnetic driving coils 63 and 64 are connected to be energized by arc 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 arc 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 difficult to insert magnetic coils into a circuit as the number of turns (i.e. inductance) increases. It also becomes more difficult 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 effect 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 is connected to one terminal ofa 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 ofthe coil 79 may be connected to the body member as at 83. Thus, the coil 79 is energized by arc current to produce a magnetic field which spins the are 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 are 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 circuit interrupter of FIG. 8 is described and claimed in my divisional patent application referred to above.

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 SF 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 applications flied Jan. 26, l965, Ser. No. 428,077 now Pat. No. 3,379,848 by Robert G. Colclaser, Jr. and Frank L. Reese, and filed Sept. 18, I964, Ser. No. 397,512, now Pat. No. 3,291,949 by 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.

lclaim:

1. A fluid-blast circuit interrupter including separable main contact means for establishing a main current are, piston means for generating fluid under pressure and forcing the same against the main current arc, electromagnetic means including a pair of accelerating coils for assisting the piston means in rapidly generating fluid under pressure, movable probe means insulated from the separable main contact means electrically connected to said two accelerating coils, and

means utilizing said generated pressure from the movement of the piston means for effecting arc transfer from the separable main contact means to the movable probe means to thereby insert said two accelerating coils serially into the electrical circuit, whereby piston operation is mechanically assisted.

2. The combination according to claim 1, wherein at least one of the separable main contact means is a hollow contact and has the fluid flow passing therethrough.

3. The combination according to claim I. wherein the movable probe means is centrally located with respect to the stationary contact means.

4. The combination of claim 1, wherein the piston means comprises a movable operating cylinder movable over a relatively stationary piston.

5. The combination of claim 4, wherein one of the accelerating coils moves with the movable operating cylinder and the other accelerating coil is supported by the relatively stationary piston.

6. The combination of claim 1, wherein the piston means includes an orifice structure for more positively directing fluid flow against the established main current arc.

7. The combination ofclaim 1, wherein one of the separable main contacts is a nozzle-shaped movable contact.

8. The combination ofclaim 4, wherein the movable operating cylinder carries a nozzle-shaped movable contact therewith.

9. The combination of claim 8, wherein the other contact is a relatively stationary plug-type contact penetrating the movable nozzle-shaped contact in the closed-circuit position of the interrupter.

10. The combination of claim 6. wherein the movable probe means is in the orifice structure.

11. The combination of claim 6 wherein the orifice structure is movable and provides both lateral and axial venting of the fluid under pressure.

12. The combination of claim 1. wherein the fluid is sulfur hexafluoride (SF gas.

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