US 3526735 A
Description (OCR text may contain errors)
Sept. 1, 1970 K. H. DATE.
REPEATING CIRCUIT INTERRUPTER 2 Sheets-Sheet 1 Filed June 15, 1966 INVENTOR. Kazuo H. Date Sept. 1, 1970 K. H. DATE REPEATING CIRCUIT INTERRUPTER 2 Sheets-Sheet 2 Filed June 15, 1966 A R. 8 @J 0 1C N A rum, 1 a r N 0 J M a 1-- I r W Llwlx mw w N w Z mfi m 0 mm H mm K V r B QM, 3 L M QM, mN k Dm w I uh M w w %Q\ Q wk 0 R v N0 u o 3 ms 0 m in l my H @mm $0 an QQ m MN 0 \h as 0 Nu WW 9 k% MIN m m.
United States Patent O 3,526,735 REPEATIN G CIRCUIT INTERRUPTER Kazuo Henry Date, South Milwaukee, Wis., assignor to McGraw-Edison Company, Milwaukee, Wis., a corporation of Delaware Filed June 15, 1966, Ser. No. 557,660 Int. Cl. H01h 3/00 US. Cl. 200-153 7 Claims ABSTRACT OF THE DISCLOSURE An operating mechanism for a vacuum circuit interrupter is provided in which an operating means moves between first and second positions in which the electrodes of the vacuum interrupter are respectively closed and open. The operating means is held in its second position by the operating mechanism to prevent reclosing of the electrodes until the operating mechanism releases the holding means. The operating mechanism and a closing means cooperate to reclose the electrodes and charge a resilient opening means through a toggle linkage means. The linkage means is connected to the resilient means and the operating means so that the mechanical lever advantage of the linkage means is utilized in charging the resilient means to thereby reduce the amount of force that must be applied to charge the resilient means.
This invention relates to repeating circuit interrupters and, more particularly, to an operating mechanism for repeating circuit interrupters having vacuum current interrupting devices.
Because of the many characteristic differences. between interrupters of the vacuum type and those employing a dielectric medium, conventional operating mechanisms are not satisfactory in circuit breakers employing vacuum interrupters. For example, one such difference is the relatively short opening stroke characteristic of vacuum devices which introduces problems of rapid deceleration and contact bounce. In addition, there is a greater tendency for the contacts in vacuum interrupters to weld shut, wherein means are required for impacting the contacts during an opening operation. Further, vacuum interrupters are generally provided with butt type contacts requiring greater contact pressure than circuit breakers having contacts with multiple points of engagement.
A primary object of the invention is to provide a circuit breaker operating mechanism having specific application to vacuum type circuit interrupters.
Another object of the invention is to provide means for decelerating the moving contact in vacuum circuit interrupters.
Yet another object of the invention is to provide means for preventing contact bounce in vacuum type circuit interrupters.
A further object of the invention is to provide means for breaking welds in the contact of a vacuum type circuit interrupter.
Yet another object of the invention is to provide a circuit breaker operating mechanism capable of supplying relatively high contact pressure to the butt contacts of a vacuum circuit interrupter.
Still another object of the invention is to provide a vacuum circuit interrupter having movable contact impacting means for weld breaking with means for supporting the vacuum envelope and terminal bushings independently of the movable contact.
These and other objects and advantages of the instant invention will become more apparent from the detailed description thereof, taken with the accompanying drawings in which:
FIG. 1 is a side elevational view, with parts broken away, of a circuit breaker incorporating the instant invention;
FIG. 2 is a fragmentary view of the circuit breaker illustrated in FIG. 1; and
FIGS. 3, 4 and 5 show the circuit breaker operating mechanism according to the instant invention in its various operative positions.
Referring now to the drawings in greater detail, FIG. 1 shows a polyphase repeating circuit breaker having current interrupters 11 of the vacuum type. The circuit breaker 10 is provided with a metallic enclosure 12 having a cover 13 which supports porcelain terminal bushings 14 for connection to conductors (not shown). In addition conductors (also not shown) extend from the lower ends of bushings 14 to connect with the movable and stationary electrodes or contacts 15 and 16, respectively, of the vacuum circuit interrupters 11.
The details of the vacuum circuit interrupter 11 form no part of the instant invention and, accordingly, will v not be discussed in detail for the sake of brevity. For a more complete description of the vacuum circuit interrupter, reference is made to co-pending application US. Pat. No. 3,280,286, issued to I ohn W. Ranheim on Oct. 18, 1966, and assigned to the assignee of the instant invention.
A suspension assembly 17 rigidly supports each of the vacuum interrupter assemblies 11 below the cover 13, and each assembly 17 includes an open-ended rectangular bracket 18 which is suitably affixed at its top to the cover 13. A pair of insulating support rods 19 are secured to the lower surface of bracket 18 and extend downwardly therefrom. In addition a first support plate 20 is secured to the lower end of the insulating rods 19 and in turn supports a second plurality of insulating rods 22 which carry a second support plate 23 at their lower ends. The upper and lower ends of the vacuum interrupter 11 are rigidly affixed to the support plates 20 and 23, respectively. Because of the rigid manner in which the interrupters 1 1 are supported, it is possible during an opening operation, as will be discussed in greater detail hereinafter, to impact the movable electrodes 15 with a great deal of force to break any welding that may exist with the stationary electrodes 16. This is in contrast to certain prior art circuit breakers where the vacuum interrupters are part of or suspended from the porcelain insulators wherein such impacting of the stationary contacts or electrodes is not possible.
An operating rod 25 extends lengthwise of the housing 12 and beneath the cover 13 and is connected by pins 26 to the knee of a toggle linkage 27 associated with each phase, and each of which comprises a first link 28 and a second link 30. Each of the first links 28 is pivotally connected at their other ends to fixed pins 31 and the other ends of the second links 30- are pivotally connected to the upper end of an insulating contact rod 33 which extends downwardly into the interrupting assembly 11 of each phase to engage the movable electrodes 15 so that said contacts in each phase may be simultaneously opened.
FIG. 2 shows in greater detail the connection between each toggle link 30 and its contact rod 33 to include a stem 34 afiixed by a pin 35 in a telescoping relation to the upper end of the rod 33. Each stem 34 extends upwardly from its rod 33 and into a sleeve 36 to which it is connected by a pin 37 which extends through the stem 34 and into slots 38 formed in the opposite side of sleeve 36. In addition, the upper end of each sleeve 36 is pivotally connected to its associated toggle link 30 by a pin 39. A contact pressure spring 40 surrounds each stem 34 and extends between a cup-shaped member 42 mounted in an inverted relation at the upper end of the rod 33 and a washer 43 mounted at the lower end of the sleeve 36.
Switch opening energy for each of the movable electrodes is provided by an opening spring 45 affixed at one end by a pin 46 to the operating rod and at its other end to a pin 47 fixed to the casing 12. It will be appreciated that movement of the rod 25 towards the right, as viewed in FIG. 1, would charge the opening spring and straighten the toggle linkages 27 to thereby move the contact rods 33 downwardly to close the movable electrodes 15. On the other hand, when the rod 25 is released for movement toward the left in FIG. 1 and under the in fiuence of spring 45, the toggle linkages 27 will collapse to raise the rods 33 and thereby open the movable electrodes 15.
An operating mechanism 50, according to the instant invention, is disposed in a metallic housing 51 suitably affixed adjacent one end of the enclosure 12. As seen in FIG. 1, the operating rod 25 extends from the enclosure 12 and into the housing 51 where it is coupled to the operating mechanism 50. A control 53 for initiating the various opening and closing operations of the circuit breaker 10, is disposed within a separate metallic housing and is electrically connected to the mechanism by a cable 54. As will be understood by those skilled in the art, many types of controls which are suitable for use with the circuit breaker 10 are well known, and accordingly, control 53 will not be discussed in detail. For a complete description of a control capable of use with the disclosed circuit breaker, reference is made to U.S. Pat. No. 3,100,854, issued to Richard E. Riebs on Aug. 13, 1963, and assigned to the assignee of the instant invention.
As seen in FIGS. 3-5, the operating mechanism 50 includes a first latch assembly 56 for holding the electrodes 15, 16 in a closed position against the opening spring 45, a second latch assembly 57 for holding the contacts 15, 16 in an open position to prevent contact rebound and a reset assembly 58 for resetting the first latch assembly 56 and for releasing the second latch assembly 57.
A trip solenoid 62 is provided for releasing the first latch assembly 56 so that the operating rod 25 is freed for movement to a switch open position under the influence of opening spring 45. After a switch opening operation, a motor 64 is operative through a gear mechanism 65 and a reclosing lever 66 to actuate the reset assembly 58.
The first latch assembly 56 includes a latch member 68 which is pivotally mounted about a fixed pin 70 and which is urged toward clockwise rotation and against a stop pin 71 by a small spring 72. An integral arm 74 extends outwardly from the latch member 68 and carries a pin 75 at its outer end which normally lies in the path of the trip solenoids plunger 77.
The first latch assembly 56 also includes a latch lever pivotally mounted intermediate its ends about a pin 81 carried by one end of a link 82 which in turn is pivotally mounted intermediate its ends on a fixed shaft 84. A roller 86 is mounted at one end of latch lever 80 and cooperatively engages the latch 68 while the other end of lever 80 is pivotally connected to one end of a link 88. The other end of link 88 is pivotally connected to one arm of a bell crank 89 which is pivotally mounted about a fixed shaft 90 and whose other arm is pivotally connected to the operating rod 25.
It will be appreciated from the description thus far that when the electrodes 15, 16 are in their closed position, as shown in FIG. 3, the opening spring 45 will be extended and will urge the operating rod 25 toward the left to rotate the bell crank 89 and the latch lever 80 counterclockwise. Such movement is prevented, however, by the latch 68 which lies in the path of roller 86 to prevent rotation of the latch lever 80.
The second latch assembly 57 includes a latch crank 94 pivotally mounted on a fixed shaft 95 and having a latch surface 97 for cooperatively engaging a pin 98 carried by the operating rod 25. A long link 100 is provided for interconnecting the other arm of the latch crank 94 with the other end of the link 82.
The reset assembly 58 includes a reset latch pivotally mounted about fixed shaft 106 and having a latch tip 108 engageable with a latch arm 109 pivotally mounted on a second fixed shaft 110. In addition, the assembly 58 includes a reset lever 112 carried on a fixed shaft 113 and a first link 115 which couples the lever 112 to the free end of the latch arm 109 and a second link 116 which couples the arm 109 and the link 115 to the pin 81 carried by the latch lever 80.
When the operating assembly 50 is in its position shown in FIG. 3 the electrodes 15, 16 are in their closed position and the opening spring 45 is extended. Should the control assembly 53 sense the necessity for a switch opening operation, it will cause the energization of the trip coil 62 in a manner well known in the art. This causes the solenoid plunger 77 to move upwardly and impact the pin 75 carried by the latch 68 and thereby to rotate the latch counterclockwise from its position shown in FIG. 3 to its position shown in FIG. 4. This frees the latch lever 80 and the bell crank 89 for counterclockwise rotation about the pin 81 and shaft 90, respectively, as the opening spring 45 moves the operating rod 25 toward the left, as viewed in FIGS. 3 and 4. In addition, this movement collapses the toggle links 27 associated with each phase to move the sleeves 36 upwardly.
It will be recalled that when the electrodes 15, 16 are in their closed position and the opening spring is extended, as seen in FIG. 3, the pin 37 in the stem 34 is initially intermediate the ends of the slot 38 formed in the sleeve 36. As a result, therefore, when the sleeve 36 initially begins moving upwardly during a switch opening operation, the contact rod 33 will remain in its switch closed position. After the sleeve 36 has moved upwardly a short distance, however, the slots 38 will impact the pins 37 at a relatively high speed so that the impact force will be sutficient to break any welding which may exist in the electrodes 15, 16. It will be appreciated, too, that this initial opening movement of the sleeve 36 under the influence of opening spring 45 will be aided by the contact pressure springs 40.
The operating mechanism 50 is able to impact the movable electrodes 15 with a high opening force because each of the interrupters 11 is relatively rigidly mounted between the plates 20 and 23 and by the insulating support rods 19 and 22. This rigid mounting insures that the refractory portions of the interrupter 11 will not be unduly stressed by the impacting force. Also because the movable electrodes 15 are mounted independently of the terminal bushings 14, the latter will not be subjected to the impacting force.
As seen in FIGS. 3 and 4, the engagement between the latch arm 109 and the reset latch 105 will hold the lever 82 inactive during the initial rotational movement of the latch lever 80 and the bell crank 89. As a result, the latch crank 94 will also remain inactive so that the pin 98 will engage the latch surface 97 when the operating rod 25 reaches its full switch-open position shown in FIG. 4. As a result, return movement of the operating rod 25 is prevented so that the movable electrodes 15 are prevented from rebounding toward their closed positions.
After the operating rod 25 reaches its fully open position to rotate the bell crank 89 and the latch lever 80 counterclockwise, the left end of the latch lever 80 will engage the reset latch 105 to rotate the latter counterclockwise against a small reset spring 120 as seen in FIG. 4. This releases the latch arm 109 so that the levers 82 and 112 are free to pivot clockwise about their respective shafts 84 and 113 from their positions shown in FIG. 4 to their positions shown in FIG. 5. This rotational movement of the levers 82 and 112 may be brought about either as a result of their own weight or a small spring (not shown) may be provided for this purpose.
As the lever 82 pivots, the pin 81, which rotatably supports the latch lever 80, will move the lever 80 downwardly and against a stop 121, whereupon the roller 86 will again be positioned below the latch 68. In addition,
clockwise pivotal movement of the lever 82 Will elevate the link 100 to rotate the latch crank 94 counterclockwise to move the latch surface away from the pin 98. This places the mechanism 50 in a reset position in preparation for a reclosing operation.
Reclosing of the electrodes 15, 16 may be initiated in any manner well known in the art, such as, for example, by means of a limit switch 122 positioned below the reset lever 112. When the mechanism 50 reaches its reset position, shown in FIG. 5, the reset lever 112 will engage the limit switch 122, thereby completing an energizing circuit to the reclosing motor 64 which, in turn, rotates the reclosing lever 66 counterclockwise. As the reset lever 66 rotates, a roller 123 on its free end will engage the underside of the reset lever 112 to rotate the latter counterclockwise, thereby producing clockwise rotation in the latch arm 109 to move it into engagement with the latch 105. Also, because the roller 86 carried by the latch lever 80 is disposed below the latch member 68, the lever 80 will rotate clockwise about its point of engagement with latch 68 to rotate the bell crank 89 clockwise thereby to extend the opening spring 45 and to reclose the movable electrodes 15. In addition, as the latch lever 80 rotates, it will move the pin 81 in a generally upward direction to produce counterclockwise rotation in lever 82 to thereby return the latch crank 94 to its initial position shown in FIG. 3. In this manner the mechanism 50 is reset in preparation for subsequent switch opening operation.
Should a tripping operation become necessary while the main electrodes 15, 16 are being reclosed, solenoid coil 62 may be energized to rotate the latch 68 and release the latch lever 80 for counterclockwise rotation to allow a switch opening operation even though the reclosing lever '66 is in its reclosing position.
Those skilled in the art will appreciate that the force necessary to extend the opening spring 45 and to compress the contact pressure spring 40 will increase as the charging of these springs proceeds. In order to eliminate the necessity for providing an inordinately large motor 64, the springs 40 and 45 are coupled to the operating rod through the toggle linkage mechanism 27. Since the leverage expected by the toggle links 28 and increases as they approach their straight line position, a greater spring charging force will be available at the time when the springs and require a greater force for charging. In this manner, a relatively smaller reclosing motor 64 may be employed than would normally be necessary.
While only a single embodiment of the invention has been shown and described, it is not intended to be limited thereby.
1. In a circuit interrupter having a vacuum envelope and switch means including a pair of electrodes having adjacent ends enclosed within said envelope, one of said electrodes being movable between open and closed positions with the other electrodes, the combination comprising:
resilient switch opening means coupled to said movable electrode;
an operating mechanism including,
an operating means connected to said movable electrode and said resilient switch opening means and having a first position wherein said movable electrode is in its closed position and said resilient switch opening means is charged and being movable to a second position by said resilient means wherein said movable electrode is in its open position,
first means engaging said operating means for holding the operating means in its first position, release means operable to free said operating means for movement from its first to its second position,
second means maintained in a normal position when said operating means is in its first and second positions for engaging and holding the operating means when the latter is in its second position,
third means coupled to said second means for moving the second means out of its normal position after the operating means and movable electrodes have respectively moved to their second and open posi tions; and
switch closing means engaging said operating mechanism for returning said operating means and movable electrode to their respective first and closed positions and returning said second means to its normal position.
2. The circuit interrupter set forth in claim 1 wherein said second means is disengaged from said operating means when said operating means is in its first position and engaged with said operating means when it is in its second position and the second means is in its normal position.
3. The circuit interrupter set forth in claim 1 wherein said second means comprises second latch means having a position in latched engagement with said operating means when said operating means is in its second position and said second means is in its normal position.
4. The circuit interrupter set forth in claim 1 wherein:
said third means includes linkage means having a rigid condition and being connected to said second means for holding the second means in its normal position and for moving said second means out of its normal position upon release of the linkage means from said rigid condition; and
fourth means having a position in engagement with said linkage means to hold the linkage means in its rigid condition and being disengageable from said linkage means by said operating mechanism to release said linkage means from its rigid condition after said movable electrode moves to its open position.
5. The circuit interrupter set forth in claim 4 wherein said first means is movable to a position in engagement with said fourth means to disengage the fourth means from said linkage means.
6. The circuit interru ter set forth in claim 1 wherein:
said third means includes linkage means connected to said second means for moving said second means out of its normal position; and
said second means comprises second latch means connected to said linkage means and being in latched engagement with said operating means when said operating means is in its second position and said second means is in its normal position, said second latch means being movable out of latched engagement with said operating means when said second means is moved out of its normal position by said linkage means.
7. The circuit interrupter set forth in claim 6 wherein:
said switch closing means has a position in engagement with said linkage means; said operating mechanism includes fourth means having engaged and disengaged positions with the linkage means for releasably holding said linkage means; and
said linkage means is movable to a rigid condition in engagement with the fourth means by said switch closing means, said linkage means holding the second means in said normal position when in said rigid condition, said linkage means being movable to a collapsed condition when disengaged with the fourth means to move said second means out of its normal position, said linkage means remaining in said collapsed condition until returned to said rigid condition by the switch closing means.
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