MXPA99004243A - High current electrical switch with interlaced poles and unit modules for interference adjustment of union blocks in trimmed hands in molded boxes - Google Patents

Abstract

The present invention relates to molded case electrical switches such as circuit breakers, network protectors, disconnect switches and transfer switches, are secured together side by side by linking blocks having tongues that extend along their lengths. side walls that link cutout grooves that trim the irregular surfaces of the facing side walls of the molded interruption boxes with an interference fit. Separate connecting blocks for the front and rear sections of the molded case are pushed into place and retained by means of bolts that link flanges to the molded case. The poles are arranged in parallel by means of external conductors in any desired configuration so that standard switches can be used without modification to the meter.

Description

HIGH CURRENT ELECTRICAL SWITCH WITH ENTRELAZADOS POLES AND MODULES UNITED BY ADJUSTMENT BY INTERFERENCE OF UNION BLOCKS IN HIDES TRIMMED IN MOLDED BOXES Background of the Invention Field of the Invention This invention relates to electrical switching apparatus for electric power distribution systems. More particularly, it relates to the joining of multiple interrupting units together side by side and electrically connecting them to share the current load. Background Information Electrical switching devices for electric power distribution systems include circuit breakers and network protectors that provide protection, and electrical switches to isolate parts of the distribution system and to transfer between alternative sources. Although families of such switches are produced having a range of nominal current capacities, some applications require higher current ratings than those available from standard units. It is not practical to make a dedicated switch for such applications in view of the limited demand. It is therefore common to mount a pair of such switches side by side and connect the poles to share the current. This construction technique in parallel is of particular value with molded case switches where the investment required in the molded case is quite large and can be avoided by joining two smaller cases. Typically, the boxes have been bolted together. U.S. Patent No. 4,884,047 suggests joining the molded boxes together by bolting a separator to the two boxes and then filling the remaining space with a hardening cold setting resin and attaching reliefs on the side walls facing each other of the boxes molded. When joining two multi-pole switches side by side, it is standard practice to connect adjacent pole units, either internal to the switch or immediately outside. This produces an AABBCC phase identity. This method of connecting adjacent poles in parallel is quite simple; however, it has several disadvantages. Not only is the switch dedicated to a simple three-pole construction, but the parts used to carry out the parallel connection function are used exclusively in that larger frame size and thus are of limited production volumes. More importantly, it has been found that the amperage of the individual pole units is not additive when the adjacent poles are connected in parallel. In fact, in larger sizes, such as pole units of 2,000 or 3,000 amps, the double pole construction must be disqualified by as much as 20% compared to the combined reading of the two individual pole units. There is, therefore, a need for an improved electric switch apparatus that combines two smaller, multiple pole interrupter units to produce a unit with a higher current capacity. There is a more particular need for a simple, reliable arrangement for joining multiple pole interrupting units, especially that do not require cold setting a resin. There is also a need for such a multi-pole switch apparatus that combines two smaller units, which does not result in a substantial disqualification of the unit over the combined readings of the individual units. SUMMARY OF THE INVENTION These and other needs are met by means of the invention, which is directed to electrical switching apparatuses that include a pair of multiple pole interrupting units, side by side, having molded boxes with side walls that are confronted with irregular surfaces. Irregular surfaces include at least one cutout groove that trims the uneven surface. A joint block for joining the two molded boxes has side walls with tongues that extend generally along the side wall and dimensioned to form an interference fit with the cutout groove in a molded case side wall, of confrontation, when driving the union block between the two boxes. A stop member secured to the molded cases of the two interruption units prevents the joint block from being pushed back from the slits in the molded cases. The cut-out grooves in the molded boxes form a finger with an internal surface inclined inwards. The tongues have inner surfaces inclined inwards that link the internal surface in the fingers to effect the adjustment by interference. Preferably, the junction block has an external bonding surface adjacent to the tongue projecting towards and engages the side wall of the molded box to provide clearance for the tongue to bend outwardly from the bond block upon bonding with finger. Also preferably, the junction block has a recess that faces the inclined inner surface of the tongue to provide free space for the finger in the molded case to fold out of the box upon bonding with the tongue. With the cut-out grooves formed by the fingers placed adjacent one end of the side walls in the molded boxes, the stop member is provided at the other end for balancing the load in the joint block. Most preferred is that means be provided to prevent the tongue of the joint block from disengaging from the cutout groove by lateral displacement during the operation of the switch. This can be achieved where the finger in the molded case only extends laterally over a portion of the side wall. A projection on the joint block laterally links the finger, the tongue linking the cutout groove to prevent lateral displacement of the joint block. Typically, the molded boxes have a cutout slit in the side walls that forms handles for raising the switch, and lower cutout grooves that link a cassette to mount the interrupter unit in a cabinet. In this way, it is preferred that the joint block have tongues to link each of these cut-outs with an interference fit. In interrupting units having a molded case with a front case and a case back, each of which has one or more cut-out grooves in facing side walls, the joint block comprises a front joining block with tongues that they form interference fittings with the cut-out grooves in the side walls of the front box and a rear tie block with tongues forming an interference fit with the corresponding cut-out grooves in the side walls of the back box. The connecting block or blocks have a width dimensioned to maintain the spacing established between the adjacent poles of the interrupted units of interruption. The stop member is preferably an elongated member that links openings in flanges in two molded boxes and which also links the joint block, preferably adjacent its driven end. According to another aspect of the invention, the poles of the two interruption units side by side are joined by means of external conductors to connect corresponding poles in an interlaced manner, for example ABCABC or ABCCBA. The connections are made external to the switches, so that custom parts are not required and the flexibility for any desired type of connection is retained. BRIEF DESCRIPTION OF THE DRAWINGS Full understanding of the invention can be gained from the following description of the preferred embodiments, when read in conjunction with the accompanying drawings, in which: Figure 1 is a front view, isometric, exploded , of the electric switch apparatus according to the invention. Figure 2 is a rear view in elevation of the apparatus of Figure 1 assembled. Figure 3 is an isometric rear view of a joint front block according to the invention. Figure 4 is an isometric view similar to Figure 3 of a rear joining block. Figure 5 is an enlarged scale diagram illustrating an interference fit produced by the joint blocks of Figures 3 and 4. Figure 6 is a schematic view illustrating the pole connection of the breakdown units side by side state of the art. Figure 7 is a schematic circuit diagram illustrating the connection of the side-by-side interrupter units according to an embodiment of the invention. Figure 8 is a schematic circuit diagram illustrating the connection of the side-by-side interrupter units according to another embodiment of the invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention is directed to electrical switching apparatuses in which two interruption units are joined together side by side to form an interrupting unit with a greater ent capacity. It is applicable to electrical switching devices such as, for example, circuit breakers, network protectors, disconnect switches and transfer switches, and will be illustrated as applied to power circuit breakers. In this manner, as shown in Figures 1 and 2, the electrical switch apparatus 1 includes a pair of molded case circuit breakers 3a and 3b. For convenience, the description is aimed at joining a pair of circuit breakers; however, it will be evident that the principles apply to joining any number of such units together side by side. Likewise, the circuit breakers 3a and 3b are shown as three-pole circuit breakers. It will also be apparent that the invention is applicable to units with other pole numbers, such as for example four poles. Each of the circuit breakers 3a and 3b includes a molded case 5a and 5b. As is well known, such housings can be molded from an insulating resin such as a polyester filled with glass. In the circuit breakers shown, each of the molded cases 5a and 5b includes a front case 5af and 5bf and a rear case 5ar and 5br, which are joined together by bolts (not shown). The molded boxes 5a and 5b house the circuit breaker poles 7ax-7a3 and 7b1-7b3, respectively. The molded boxes 5 and 5b have side walls 9a and 9b with irregular surfaces Ia and llb. The irregularities in the surfaces 9a and 9b include cut-out grooves 13a and 13b that cut away the surfaces Ia and IIb. These upper cutting grooves 13a and 13b form downwardly projecting fingers 15a and 15b which serve as handles for raising the circuit breakers. Further down on the side walls 9a and 9b are the upwardly directed cutout slots 17a and 17b forming fingers projecting downwards 19a and 19b. These lower fingers or ridges 19a and 19b link a cassette (not shown) to mount the circuit breakers in an interrupter equipment cabinet (not shown).

These trimming grooves 13a and 13b and 17a and 17b in the side walls of the molded boxes 5a and 5b are used according to the invention to hold together the two circuit breakers 3a and 3b. For this purpose, the front and rear link blocks 21f and 21r are provided (see figures 3 and 4). As can be seen from figures 1 and 2, the connecting blocks 21f and 21r have side walls 23f and 23r with irregular surfaces 25f and 25r which are generally complementary to the irregular confronting surfaces 9a and 9b in the circuit breakers side with side 3a and 3b. Returning to FIGS. 3 and 4, the connecting blocks 21f and 21r have first upward extending tongues 27f and 27r extending generally along the side walls 23f and 23r. They also have upwardly extending lower tongues 29f and 29r that also extend along the side walls 23f and 23r below the tongues 27f and 27r. As can be seen from figure 2, the tongues 27f and 27r link the cut-out grooves 13a and 13b while the tongues 29f and 29r link the lower cut-out grooves 17a and 17b. The tongues 27 and 29 link the slits 13 and 17 with an interference fit which is better explained by reference to Fig. 5. As shown therein, the tongue 27 has an internal surface facing inward 31 that links an inclined inner surface inward 33 on the finger 15. The spacing of the tongue 27 from the surface 25 is such that an interference represented by the overlapping area 35 in Figure 5 is created between the inclined surfaces 31 and 33. In the exemplary apparatus 1, this interference is around 0.005. "The joint block 21 has an external bonding surface 35 that projects toward and links the box side wall at 37 to provide clearance 39 for the tongue 27. In addition, a small recess 41 is provided in a joining block 21 facing the inclined surface 31 on the tongue 27 to provide a clearance for the finger 15. The connecting blocks 21 are also made of insulating material, such as a polyester resin filled with glass, used for molded boxes. In this manner, the tongues 27 and the fingers 15 are deformable and bend outwards, respectively, in response to the interference 35. The free space and the recess 43 provide space for this deflection of the tongue 27 and the finger 15. Although not shown in detail, the lower tongues 29 and the lower trimming slits 17 have similar interference and free space that allow them to deviate. The fingers and tongues are formed with a small appendage along the front / back axis for removal of the respective molds. The interference fit extends along appended surfaces. By joining the two circuit breakers 3a and 3b, the molded boxes are reversed and the joining blocks 27f and 27r are inserted with the tongues 27f and 27r linking the cut-out grooves 13a and 13b and with the tongues 29f and 29r linking the grooves of cutout 17a and 17b. The connecting blocks are then urged parallel to the side walls 9a and 9b of the molded boxes such as by means of a mallet for effecting the interference adjustments described above. This carries the molded boxes 5a and 5b together and grasps them firmly. The connecting blocks 29f and 29r are prevented from being pushed back by stop members in the form of bolts 45 which extend laterally through openings 47 in the flanges 49a and 49b of the molded housings. These bolts 45 also link openings formed by the slots 51f and 51r in the connecting blocks 21f and 21r to prevent them from being thrown back. A single long bolt (not shown) extending between the flanges 49a and 49b can be used in place of the two shorter bolts. It has been noted that the forces generated by opening and closing the circuit breaker have a tendency to cause the connecting blocks 21f and 21r to rotate around the bolts 45. In order to prevent this lateral detachment of the tongues in the cutout grooves., projections 53 are provided in the front connecting block 21f to laterally link the lower fingers 19a and 19b that only extend laterally by a portion of the side walls 9a and 9b. Returning to Figure 1, a single operating mechanism 55 is provided in only one of the circuit breakers side by side, which in the exemplary apparatus is the circuit breaker 3a. A common pole arrow (not shown) is coupled to the poles of each of the circuit breakers and rotated by the operation mechanism 55 for synchronized opening and closing of all poles simultaneously. The electrical switch apparatus 1 further includes a standard front cover 57a for the circuit breaker 3a, with the operating mechanism and a modified cover 57b which houses the front circuit breaker 3b and extends over the joint block 21f. As can be seen from Figure 2, the lateral side terminal conductors 59a1-59b3 and the lateral load side conductors 61a1-61b3 project backwards from the housings 5a and 5b. According to the invention, the parallel arrangement of the poles of the circuit breakers side by side 3a and 3b is performed outside the circuit breakers by separate conductors, so that the circuit breakers themselves are standardized and do not require specialization for a particular arrangement in parallel. This is contrary to the standard practice illustrated in Figure 6. In this conventional array, the adjacent poles (eg, 7a2 and 7a2) are arranged in parallel, including the adjacent poles (7a3 and lb1) in the two circuit breakers. circuit that form phase B. As mentioned, such an arrangement requires disqualifying the resulting circuit breaker in as much as 20% over the rated capacities of the individual circuit breakers. The connections between the adjacent phases are made internally to the circuit breaker before disconnections 63. This requires modification of the units used in the combination side by side on the standard three-pole circuit breaker. Figure 7 illustrates that, according to the invention, the circuit breakers remain in standard form, including their disconnections 63. The parallel arrangement of the poles is achieved by separate conductors, such as conductors 65 on the line side and on the loading side. In the particular arrangement of Figure 7, the poles are interleaved in an ABCABC sequence. Figure 8 illustrates another arrangement according to the invention, in which the poles of the circuit breakers side by side 3a and 3b are arranged in parallel by separate conductors 65 'on the line side and 67' on the load side . In this configuration, the poles are arranged in parallel in an ABCCBA sequence. It will be apparent that according to the invention, the poles can be arranged in parallel in any desired configuration using the external conductors, including AABBCC. With this approach, the circuit breakers 3a and 3b remain in standard form. It is not required to specialize the circuit breakers for a particular arrangement in parallel.

Although specific embodiments of the invention have been described in detail, those skilled in the art will appreciate that various modifications and alternatives to those details may be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are intended to be illustrative only and not limitative of the scope of the invention, to which the full scope of the appended claims and any and all equivalents thereof must be given.

Claims (22)

1. CLAIMS 1. Electric switch apparatus, comprising: a pair of multiple pole interrupting units, side by side, each including a molded case with a confronting box side wall having an irregular surface, including at least one slit of cut that trims the irregular surface; a joint block having block side walls with irregular surfaces generally complementary to said irregular surfaces in said confronting box side walls, and each including at least one tongue spaced from and generally extending along said side wall of block and dimensioned to form an interference fit with said at least one cutout groove in a confronting side wall of said multiple pole breakout units, side by side, as said joint block is driven between and along said walls confronting sides to jointly hold said molded boxes; and a stop member secured to said molded cases of said pair of multiple pole interrupting units, preventing said joint block from dissociating from said molded cases. The electric switch apparatus of claim 1, wherein said cutout groove in each of said box side walls forms a finger that extends generally along said box side wall and having an inner surface inclined inwardly, said tongue having an inner surface inclined inwards that links said internal surface inclined in said finger to effect said adjustment by interference. The electrical switch apparatus of claim 2, wherein said joint block has an external engaging surface adjacent said tongue projecting toward and engages said box side wall to provide clearance for said tongue to be bent outwardly of said tongue. Union block when linking occurs with said finger. The electric switch apparatus of claim 3, wherein said joint block has a recess facing said internal surface inclined inwardly in said tongue to provide free space for said finger to bend outwardly of said box side wall upon occurrence linkage with said language. The electric switch apparatus of claim 4, wherein said molded boxes of said interrupter units include a front case with a side wall facing said at least one cutout groove forming said finger and a removable back case of said case front and having a side wall facing said at least one cutout groove forming said finger, and said joint block comprises a front joining block having side walls, each with said at least one tongue for linking said fingers in said front boxes, and a rear tie block having side walls with said at least one tongue for linking said fingers in said back boxes, and said stop member comprises a front stop member secured to said front case preventing said member from of frontal union dissociates from said frontal boxes and a rear member of stop secured to said back boxes preventing and said rear connecting block disengages from said rear boxes. The electric switch apparatus of claim 5, wherein said side walls of said molded boxes have two cutout grooves forming two fingers, and wherein said joint block has, on each side wall, two tongues that connect said two grooves to each other. trimming on side walls of box. The electric switch apparatus of claim 2, wherein said joint block has a recess facing said internal surface inclined inwardly in said tongue to provide clearance for said finger to bend outwardly from said box side wall upon occurrence linkage with said language. 8. The electric switch apparatus of claim 2, wherein said joint block includes means that prevent lateral detachment of said tongue from said trimming slit. The electric switch apparatus of claim 8, wherein said fingers extend laterally through a portion of said box side walls and said joint block has projections on said side walls laterally linking said fingers with said tongues linking said slits clipping. The electric switch apparatus of claim 9, wherein said trimming slits are adjacent one end of said box side walls, said tongues being adjacent a corresponding end of said side walls of said attachment block, and said member stop connects said joint block and said molded boxes adjacent to other ends of said molded boxes and said joint block. The electrical switch apparatus of claim 1, wherein said cut-out grooves are adjacent one end of said molded case side walls, said tongues being adjacent a corresponding end of said joint block and said molded boxes adjacent to other ends of said molded box and said joint block. The electrical switch apparatus of claim 11, wherein said joint block includes means preventing lateral detachment of said tongues from said cut-out grooves. 13. The electrical switch apparatus of claim 1, wherein said molded boxes include upper and lower cut-out grooves in said side walls and said joint block has upper and lower tongues in said aligned side walls to link said upper cut-out grooves. and inferiors. The electric switch apparatus of claim 13, wherein said molded boxes of said interrupter units include a front case with a side wall facing said at least one cutout slit forming said finger and a removable back case of said case front and having a side wall facing said at least one cutout groove forming said finger, and said joint block comprises a front joining block having side walls, each with said at least one tongue for linking said fingers in said front boxes, and a rear tie block having side walls with said at least one tongue for linking said fingers in said back boxes, and said stop member comprises a front stop member secured to said front case preventing said member from of frontal union dissociates from said frontal boxes and a rear member of stop secured to said back boxes preventing that said rear connecting block disengages from said rear boxes. The electric switch apparatus of claim 14, wherein said molded boxes include upper and lower cut-out grooves in said side walls and said joint block has upper and lower tongues in said aligned side walls to link said upper and lower cut-out grooves. . The electric switch apparatus of claim 1, wherein said molded boxes have flanges with openings adjacent a driven end of said joint block, and said stop member comprises an elongate member extending through said openings and linking said junction block adjacent said driven end between said flanges. The electric switch apparatus of claim 1, wherein the poles of each of said multiple pole interrupter units have a predetermined spacing and said joint block is dimensioned to establish said predetermined spacing between adjacent poles of said pair of units of interruption of multiple poles. 18. The electric switch apparatus of claim 1, including conductors external to said multiple pole interrupter units that connect corresponding poles of said interrupt units in parallel. 19. High current electrical switchgear, comprising: at least two multiple pole interrupter units mounted side by side; and conductor members electrically connecting corresponding poles in said at least two multiple pole interrupting units in parallel. The high current rated electric switch apparatus of claim 19, wherein each multi pole interrupter unit has a phase pole A, B and C side by side, and said conductor members connect said phase A poles together , said phase B poles together, and said phase C poles together. 21. The high current rated electrical switch apparatus of claim 19, including means rigidly connecting said at least two multiple pole breakers side by side. 22. The high current rated electric switch apparatus of claim 21, wherein said poles of each of said multiple pole interrupter units have a predetermined spacing between them and said means rigidly connecting said at least two units of interruption of multiple poles.