US2477788A - Circuit breaker with isolating switch - Google Patents

Description

Aug. 2, 1949. J. M. CUMMING CIRCUIT BREAKER WITH ISQLATING SWITCH 3 Sheets-Sheet 2 Filed July 9, 1946 Fig.

INVENTOR Jam MCummnq III N CXG-ZZVZYWATTORN Aug. 2, 1949. CUMWNG 2,477,788

CIRCUIT BREAKER WITH ISOLATING SWITCH Filed July 9, 1946 3 Sheets-Sheet 3 a 55 4 s9 Fug. 5. 5 59 c J 37 6! 4 48A 2:9 3 3 25 66 4s 1 94 f 4 WITNESSES INVENTOR C Jomes-Mcumm'inq Patented Aug. 2, 1949 CIRCUIT BREAKER WITH ISOLATING SWITCH James M. Cumming, Turtle Creek, Pa., asslgnor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application July 9, 1946, Serial No. 682,185

11 Claims. (Cl. 200-150) This invention relates to circuit interrupters in general and more particularly to operating mechanisms therefor.

In United States patent application filed June 25, 1946, Serial No. 679,087, by Winthrop M. Leeds and assigned to the assignee of the instant application, there is disclosed and claimed a novel circuit interrupter of the'type which utilizes disconnect means serially related to an arc-extinguishing unit in which opening of the circuit takes place at the unit which is followed by opening of the disconnect means. The interrupter is closed at the disconnect means in clear oil to minimize or eliminate prestriking so as to provide an interrupter especially adaptable for high speed reclosing operations. An object of my invention is to provide an improved mechanismof a type which performs substantially the same function as the mechanism disclosed in the aforesaid application.

An object of my invention is to provide an improved circuit interrupter having an improved operating mechanism interrelating disconnect means with the arc-extinguishing unit.

Another object is to provide an improved circuit interrupter having novel flushing means perative following circuit interruption.

Another object is to provide an improved mechanism in a circuit interrupter in which the operation of the arc-extinguishing unit and the disconnect means are provided in predetermined sequence.

Another object is to provide a high speed mechanism operable in predetermined sequence for properly controlling the sequence of operation between an arc-extinguishing unit and its serially related disconnect means.

Another object is to provide an improved mechanism utilized in a circuit interrupter in which a releasable connection is provided between the mechanism and the contact structure disposed within an arc-extinguishing unit so that the contact structure within the unit may be reclosed following circuit interruption.

Another object is to provide an improved circuit interrupter especially adaptable for rapid re: closing operations, in which prestriking is minimized or eliminated during the closing operation.

Further objects and advantages will readily become apparent upon a reading of the following specification taken in conjunction with the drawings in which:

Figure 1 is a side elevational view of a circuit interrupter embodying my invention, partially in section, and shown in the closed circuit position;

Fig. 2 is a vertical sectional view taken along the line 1I-II of Fig. 1;

Fig. 3is an enlarged side elevational view, partly in section, of the disconnect means and the arc-extinguishing unit of Fig. 1, the interrupter being shown in the closed circuit position;

Fig. 4 is a view similar to Fig. 3 but showing the contact structure within the arc-extinguishing unit in the open circuit position;

Fig. 5 is a view similar to Fig. 3 but showing the interrupter in the fully open circuit position with the contact structure closed within the unit;

Fig. 6 is a sectional view taken along the line VI-VI of Fig. 3;

Fig. '7 isa side elevational view of a circuit interrupter embodying my invention but utilizing an improved power multiplying operating mechanism; and

Fig. 8 is a side elevational view of the interrupter shown in Fig. 7 taken at right angles thereto.

Referring to the drawings, and more particularly to Fig. 1 thereof, the reference numeral l designates a tank in which a suitable arc-extinguishing fluid 2, in this instance circuit breaker oil, is filled to the level 3. Depending from the cover 4 of the tank I are two terminal bushings 5, 6 at the lower ends of which are respectively secured disconnect means i and an arc-extinguishing unit 8. A conducting mechanism 9 electrically interconnects the disconnect means 1 and the unit 8.

An insulating operating rod 10 is employed to actuate the mechanism 8. Preferably the operating rod I0 is pivotally secured at H to a bell crank l2, the latter stationarily pivoted at iii. A link It is pivoted at l5 to the bell crank 12 and has its other end pivoted at Hi to a bell crank l'l stationarily mounted at I8. A link i9 is pivotally connected at 20 to the bell crank II. The lower end of the link is is actuated by suitable operating mechanism which may be of any conventional type and which forms no part of my present invention.

Referring more particularly to Fig. 3 which shows more clearly than Fig. 1 my improved operating mechanism, it will be noticed that the disconnect means 1 comprises a stationary disconnect contact 2! secured to the lower end of the terminal bushing 5 and cooperable with a contacting portion 22 of a disconnect lever 23. The disconnect lever 23 is actuated by the insulating operating rod I0 which is connected intermediate the ends of the disconnect lever 23, bein pivotally connected thereto by two links 24 which a,477,7ea I are connected by a pin 25 which passes through the lower endof the operating 'rod I8. The two links 24 have their lower ends mounted upon a pin 28 which extends through the opposed legs 21 of the disconnect lever 23. Preferably a washer-shaped spacer 28 spaces the links 24 on the pin 28.

The right-hand end of the disconnect lever 23 is pivoted at 29 to the left-hand ends of two actuating members 38, the right-hand ends of which are stationarily pivoted on a pin 3|, the

ends of which are supported by the legs 32 of a I U-shaped bracket 33, the latter being secured in any suitable manner to the lower end of the arcextinguishing unit 8.

A metallic plate 34 is secured by any suitable means, such as by welding, between the righthand ends of the actuating members 38 having an adjustable stop screw 35 threadedly secured thereinto. The adjustable stop screw 35 makes abutting engagement in the open circuit position of the interrupter, as shown in Fig. 5, with a web portion 36 of the U-shaped bracket 33.

A pair of compression springs 31 serve as biasing means to bias the actuating levers 38 in a counterclockwise direction about the pin 3i. The upper ends of the compression springs 31 seat against the lower plate 38 of the arc-extinguishing unit 8. The lower ends of the compression springs 31 seat upon right angle brackets 39 secured as by welding to the sides of the actuating levers 38.

To each of the two actuating levers 38 is pivotally mounted a latch 48, the latter being pivoted at 4| to the side of the actuating lever 38 and biased in a clockwise direction thereabout by a compression spring 42. The right-hand end of the compression spring 42 seats in a cup preferably made an integral portion ofthe actuating lever 38. The left-hand end of the compression spring 42 seats against the lower end of the latch 48. The two latches 40 serve to latch a pin 44 which passes through the sides of a pair of operating levers 45, the latter being pivotally mounted adjacent their left-hand ends to a pin 46 which is supported by a, U-shaped bracket 41 secured to the lower end of the unit 8.

Two links 48 have their lower ends pivotally mounted on the pin 44 and have their upper ends supported by a pin 49 which extends through the lower end of a rod 58 having a piston integrally formed therewith and movable within a piston chamber 52. The piston chamber has an inlet port 53 and an exhaust port 54. Associated with the piston chamber 52 is a movable valve 55 which is slidable within the upper end of the piston chamber 52.

The exhaust port 54 leads into the interior of the arc-extinguishing unit 8 in which are interruption occurs. In this particular instance, the arc-extinguishing unit 8 is of the type which establishes both a pressure-generating arc and an interrupting arc. The contact structure within the unit 8 consists of a pivotally mounted pressure-generating contact 56 cooperable with an intermediate contact 51 to establish a pressuregenerating are 58, as shown in Fig. 4. Cooperable with the lower end of the intermediate contact 51 is a lower movable contact 59 having its lower end formed in the shape of a block 60 and pivotally mounted on a pin 6| which passes through slots 62 formed at the right-hand ends of the operating levers 45. A flexible conductor 63 electrically interconnects the block 68 with the disconnect lever 23 by means of bolts 64 which pass into a metallic block 85 fixedly secured, as by welding, between the right-hand ends 68 of the legs 21 of the disconnect lever 23.

The intermediate contact 81 is biased downwardly by a compression spring 61. The passage structure within the' unit 8 is formed by the placing of suitably shaped insulating plates in abutting engagement. Preferably the passage structure is of the type set forth in United States patent application filed November 11, 1942, Serial No. 465,244, now United States Patent 2,406,469, issued August 2'1, 1946, by Leon R.

Ludwig, Winthrop M. Leeds and Benjamin P- Baker and assigned to the assignee of the instant application. The contact structure within the unit 8 forms the pressure-generating arc 58 before the establishing of the interrupting are 68. Fluid under pressure is forced from the pressure-generating are 58 downwardly through vertical flow passages 69 and through inlet passages 18 toward the interrupting arc 68 through orifices 1| and out through exhaust passages 12. Reference may be had to the aforesaid Patent 2,406,469 for the plate configuration.

Preferably the piston 51 has the upper end thereof extended into an insulating rod 13 which is biased upwardly by a compression spring 14, the upper end of which seats upon a cap 15 secured to the upper end of the rod 13.

In the closed circuit position of the inter- 1 rupter, as shown in Figs. 1 and 3, the electrical circuit thereunto includes line terminal 16, terminal bushing 5, stationary disconnect contact 21, contacting portion 22, movable disconnect lever 23, flexible conductor 63, block 60, lower movable contact 59, intermediate contact 51, pressure-generating contact 56, top dome casting 11, contact foot 18 (Fig. 1), terminal bushing 6 to line terminal 18. During the opening operation the operating mechanism 88 causes upward movement of the link I8 which through the two bell cranks l2, l1 causes downward movement of the insulating operating rod ID.

The downward movement of the rod l8 permits the compression springs 31, which are relatively strong, to force the actuating member 38 downwardly, the left-hand end 22 of the disconnect lever 23 pivoting about the lower end of the stationary disconnect contact 2| in a manner, as more clearly shown in Fig. 4. The latch 48 is effective during this time to cause clockwise rotation of the operating levers 45 about the stationary pivot 46 to simultaneously cause downward movement of the lower movable contact 53 and charging operation of the flushing means 8!. The downward movement of the lower movable contact 59 sequentially causes establishing of the pressure-generating arc 58 and the interrupting are 68 to thus cause fluid flow in the manner described in Patent 2,406,469 to result in extinction of the interrupting are 68.

The counterclockwise rotation of the actuating levers 38 continues until the adjustable stop screw 35 strikes the Web 36, at which time the counterclockwise rotation of the actuating levers 38 ceases.

At this time the disconnect lever 23 which has been heeling about the stationary disconnect contact 21 now rotates in a counterclockwise direction about the pin 29 by virtue of continued downward movement of the operating rod l8. This motion continues until the right-hand ends 86 of the legs 21 of the disconnect lever 23 strike the trip portions 82 of the latches 48 to thereby effect release of the releasable connection 83 between the operating levers ll and the actuating levers ll. when this occurs'the compression spring I4 is eilective to cause upward movement of the rod 13 and hence upward movement of piston SI, operating levers ll and also upward movement otlower movable contact 58. Fig. 5 shows the position 01' the contact structure and the piston means II in the retracted position while the disconnect lever 23 is in its fully open circuit position.

To close the interrupter it is merely necessary to cause upward movement of the operating rod I. which first closes the disconnect gap between the stationary and movable disconnect contacts II, 22. when the movable disconnect contact It strikes the stationary disconnect contact 2i, further upward movement of the operating rod ll causes the disconnect lever 18 to heel about the stationary disconnect contact 2| to thereby force the right-hand ends SI of the legs 21 of the disconnect lever upwardly to effect relatching of the releasable connection ll. Fig. 3 shows the position of the several parts in the closed circuit position.

It'will be observed that during the opening stroke the downward movement the piston II within the piston chamber 52 draws the movable valve l5 downwardly to thereby close the exhaust port It and open the inlet port 53. Thus the pressure generated within the unit I has no effect upon the recharging of the flushing means ll inasmuch as the valve I! strikes the sleeve 84. Thus downward movement of the piston ii by suction action draws fresh oil through the inlet port 53 and into the piston chamber 52, this occurring during the initial portion of the opening operation when are interruption is occurring within the unit I.

Following are interruption and consequent circuit interruption within the unit 8, the continued downward movement of operating rod l0 after actuating levers II have stopped their rotation, causes release of the releasable connection 83 to permit the compression spring H to be effective to cause upward movement of the piston- II to thereby force the valve 55 upwardly to the position shown in Figs. 3 and 5. This movement of the valve 55 closes the inlet port 53 and opens the exhaust port 54 to thereby permit the piston to force fresh oil of high dielectric strength into the vertical flow passages I! of the unit 8 to flush out the interior of the unit 8.

From the foregoing description, it will be apparent that I have provided an improved mechanism for a circuit interrupter oi. the rapid reclosing type, in which the contact structure is reclosed within the unit 8 and the circuit is closed at the disconnect contacts 2| 22. Thus prestriking is eliminated and the operation of the flushing means BI is effective to condition the interior oi the unit 8 so that should a reopening operation be desired, arc interruption may be readily eftected.

The mechanism and the unit design is effective to eliminate the necessity for multiplying levers in the pole unit. The fact that the lower end of the disconnect lever is hinged around a controlled !ulcrum eliminates the necessity for insulated guides and straight line motion mechanism. A torque drive from the operating mechanism to the contacts is now possible with this contact element. If necessary, a toggle bell crank arrangement could be added for additional power, as shown in Fig. 7 and 8, where the operating mechanism is weak but a mechanism of 6 suillcient power to do the work under one to one ratio conditions could be used.' This method 01' grid break and disconnect furthermore allows a large overtravel in the breaker litt rod. This overtravel can be used very conveniently for a simple air exhaust arrangement where air operated mechanisms are used. The overtravel can mechanically operate a valve after the breaker.

is latched, simplifying the dumping problem in air mechanisms.

In the power multiplying mechanism of Figs. 7 and 8, the link It is pivotally connected at II to the bell crank 88, the latter being stationarily pivoted at 81. A link ll mechanically interconnects the bell crank 88 with the bell crank ll which is of the construction previously described in connection with Fig. 2. This power multiplying arrangement of Figs. 7 and 8 may be used where desired.

The mechanism 8 provided is very high speed in operation and is effective to bring about the desired sequence in operation. Also the interrupter is especially adaptable for rapid reclosing operations where contamination of the liquid in the interior of the unit due to prestriking of the arc during the closing stroke should be be avoided. The addition of the flushing means rapidly conditions the unit 8 for closing followed by an immediate reopening operation if the electrical conditions of the circuit dictate such a reopening operation.

Although I have shown and described a speciiic structure, it is to be clearly understood that the same was merely for the purpose of illustration and that changes and modifications may readily be made therein by those skilled in the art without departing from the spirit and scope of the appended claims.

I claim as my invention:

1, In a circuit interrupter, a tank filled with liquid, a terminal bushing extending into the tank, a stationary disconnect contact secured to the interior end of the bushing, a second terminal bushing extending into the tank, an arc-extinguishing unit secured to the interior end oi the second bushing, an actuating lever, means secured to the unit and pivotally mounting the actuating lever adjacent one end thereof, a movable disconnect lever having a movable disconnect contact portion adjacent one end thereof, means pivotal-1y mounting the other end of the actuating lever to the other end of the disconnect lever, separable contact structure disposed within the unit, a releasable connection between the contact structure and the actuating lever, and means for releasing the connection in the open position of the actuating lever.

2. In a circuit interrupter, a tank filled with liquid, a terminal bushing extending into the tank, a stationary disconnect contact secured to the interior end of the bushing, a second terminal bushing extending into the tank, an arc-extinguishing unit secured to the interior end of the second bushing, an actuating lever, means secured to the unit and pivotally mounting the actuating lever adjacent one end thereof, a movable disconnect lever having a movable disconnect contact portion adjacent one end thereof, means pivotally mounting the other end of the actuating lever to the other end of the disconnect lever, means biasing the actuating lever aboutits pivotal mounting, separable contact structure disposed within the unit, means electrically connecting the contact structure in series with the disconnect lever, a releasable connection between the-contact structure and the actuating member,

means for releasing the connection in the open position of the actuating lever, and an operating rod connected intermediate the ends of the disconnect -lever to efiect the actuation thereof.

3. In a circuit interrupter, a tank filled with liquid, a terminal bushing extending into the tank, a stationary disconnect contact secured to the interior end of the bushing, a second terminal bushing extending into the tank, an arc-extinguishing unit secured to the interior end 01' the second bushing, an actuating lever, means secured to the unit and pivotally mounting the actuating lever adjacent one end thereof, a movable disconnect lever, means pivotally mounting the other end of the actuating lever to one end of the disconnect lever. contact structure disposed within the unit, means connecting the contact structure in series with the disconnect lever, means biasing the contact structure to the closed position, releasable means connecting the contact structure with the actuating lever during the opening movement of the latter, and means releasing the releasable means in the open position of the actuating lever to permit reclosure of the contact structure.

4. In a circuit interrupter, stationary disconnect means, movable disconnect means including a disconnect lever, an arc-extinguishing unit, a movable contact, an operating lever, means connecting the movable contact to the operating lever, means pivotally mounting the operating lever adjacent one end, an actuating lever, means pivotally mounting the actuating lever adjacent one end, means connecting the other end of the actuating lever to one end of the disconnect lever, means providing a releasable connection between the operating lever and the actuating lever, and means responsive to the fully open position of the disconnect lever to cause release of the releasable connection.

5. In a circuit interrupter, stationary disconnect means, movable disconnect means including a disconnect lever, an arc-extinguishing unit, a movable contact, an operating lever, means con.- necting the movable contact to the operating lever, means pivotally mounting the operating lever adjacent one end, an actuating lever, means pivotally mounting the actuating lever adjacent one end, means connecting the other end of the actuating lever to one end of the disconnect lever, means providing a releasable connection between the operating lever and the actuating lever, a piston for moving fluid within the unit, and means connecting the piston to the operating lever.

6. In a circuit interrupter, stationary disconnect means, movable disconnect means including a disconnect lever, an arc-extinguishing unit, a movable contact, an operating lever, means connecting the movable contact to the operating lever, means pivotally mounting the operating lever adjacent one end, an actuating lever, means pivotally mounting the actuating lever adjacent one end, means connecting the other end of the actuating lever to one end of the disconnect lever, means providing a releasable connection between the operating lever and the actuating lever, means biasing the actuating lever about its pivoted mounting, an operating rod connected intermediate the ends of the disconnect lever, flushing means for the unit including a piston, and means connecting the piston to the operating lever.

7. In a circuit interrupter, stationary disconnect means, movable disconnect means including a disconnect lever, an arc-extinguishing unit, a

movable contact, an operating lever, means connecting the movable contact to the operating lever, means pivotally mounting the operating lever adjacent one end, an actuating lever, means pivotally mounting the actuating lever adjacent one end, means connecting the other end of the actuating lever to one end oi the disconnect lever, means providing a releasable connection between the operating lever and the actuating lever, means responsive to the fully open position of the disconnect lever to cause release of the releasable connection, flushing means for the unit including a piston, and means connecting the piston to the operating lever.

8. In a circuit interrupter, stationary disconnect means, movable disconnect means including a disconnect lever, an arc-extinguishing unit, a movable contact, an operating lever, means connecting the movable contact to the operating lever, means pivotally mounting the operating lever adjacent one end, an actuating lever, means pivotally mounting the actuating lever adjacent one end, means connecting the other end of the actuating lever to one end of the disconnect lever, means providing a releasable connection between the operating lever and the actuating lever, means biasing the movable contact to the closed position, flushing means for the unit including a piston, and means connecting the piston to the operating lever.

9. In a circuit interrupter, stationary disconnect means, movable disconnect means including a disconnect lever, an arc-extinguishing unit, a movable contact, an operating lever, means connecting the movable contact to the operating lever, means pivotally mounting the operating lever adjacent one end, an actuating lever, means pivotally mounting the actuating lever adjacent one end, means connecting the other end of the actuating lever to one end of the disconnect lever, means providing a releasable connection between the operating lever and the actuating lever, means biasing the actuating lever about its pivotal mounting, an operating rod connected intermediate the ends of the disconnect lever, a piston for moving fluid within the unit, and means connecting the piston to the operating lever.

10. A circuit interrupter including a metal enclosure, a pair of terminal bushings extending into the enclosure, a disconnect contact secured to the interior end of one terminal bushing, an arc extinguishing structure secured to the interior end of the other terminal bushing, a pair of interrupting contacts separable within the are extinguishing structure, a movable disconnect contact for engaging and disengaging the disconnect contact on the terminal bushing, said disconnect contacts being electrically connected in series with said pair of interrupting contacts between said terminal bushings, an operating rod movable to open and close the circuit, a lever connected adjacent one end to actuatesaid movable disconnect contact and pivoted intermediate its ends to said operating rod, means connected to the other end of said lever to actuate said interrupting contacts, means biasing said lever to pivot about its connection to the operating rod in the direction to keep the disconnect contacts in engagemerit during the initial movement of the operating rod in opening direction while said actuating means causes opening of the interrupting contacts in the arc extinguishing structure and a stop engageable to cause said lever to pivot about its connection to the operating rod in the opposite direction to disengage the disconnect contacts menses after the interrupting contacts have separated enough for are extinction.

11. A circuit interrupter including a metal enclosure, a pair of terminal bushings extending into the enclosure, a disconnect contact secured to the interior end of one terminal bushing, an are ex tinguishing structure secured to the interior end of the other terminal bushing, a pair of interrupting contacts separable within the arc extinguishing structure, a movable disconnect contact for engaging and disengaging the disconnect contact on the terminal bushing, said disconnect contacts being electrically connected in series with said pair of interrupting contacts between said terminal bushings, an operating rod movable to open and close the circuit, a lever connected adjacent one end to actuate said movable disconnect con tact and pivoted intermediate its ends to said op erating rod, means connected to the other end of said lever to actuate said interrupting contacts, means biasing said lever to pivot about its con nection to the operating rod in the direction to keep the disconnect contacts in engagement dur ing the initial movement of the operating rod in opening direction while said actuating means causes opening of the interrupting contacts in the are estlngoishhig ston engaceable to cause said lever to pivot about its connection to the operating rod in the oonosite direction to disengage the disconnect con after the in terruptine contacts have senarated enough for are extinction, and means for causing reens'agement oi said interrupting contacts during the later portion of the movement of the operating rod in opening direction.

JAMES M. CUMMiNG.

REFERENCES EXCEED The following references are of record in the file of this patent:

UNITED STATEE PATENTS Number l iarne Date ZAWLISF 'lhumin Feb. 16, 193? 2,172,225 Elchoiield et el Se t. s, 1939 2,288,027 Prince Apr. s, 1941 2,281,152 Quinn-ling May 5, idea 2,412, 39? Mactleil it, 19%

E OPUEKG- Number Country Date 489,569 as, lit-138

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