FI88084B - Circuit-breaker - Google Patents

Description

! 88084

power switch

The invention relates to a current switch having a plurality of movable contact members and a corresponding plurality of fixed contact members, wherein the at least one contact member comprises a spring-loaded group of contact rollers, the plurality of rollers arranged to contact the flat side surfaces of the two contact rails between the rollers, and the rollers can slide or rotate on the side surfaces when closing or opening the power switch.

Several power switches with contact rollers are known. Power Current Switches are typically equipped with a plurality of rollers mounted in pairs for each phase to distribute a large current to a plurality of parallel currents through four, six, or more rollers. However, one consequence of such a division into several rollers is that the distance traveled by the movable contact member when opening and closing it increases as the number of rollers used increases. Thus, the power switch housing and the mechanical parts inside it become correspondingly larger. The group of rollers closest to the fixed contact in the open position is subject to high consumption because: A: this group of rollers alone transfers the entire current just when the switch is opened or just after it is closed, i.e. both the rated current of the circuit breaker and its rated cut-off. ; the current is actually limited by the characteristics of this single group of rollers.

It is an object of the invention to provide a current switch arrangement for high currents, e.g. 63 A or 125 A, whereby the system. The size of the current switches and their housings can be reduced at these currents compared to known * 'switches, by shortening the travel of the contact rollers between the open and closed positions.

2 88084

According to the invention, it is proposed that the contact roller group and the contact rails cooperating with it are arranged to form a stepped connection. Such a stepped connection provides for almost simultaneous opening or closing of the different contact rollers, i.e. if one roller is in the open position, all the rollers are in the open position so that the travel of the moving contacts is reduced. Although the contact group comprises three groups of rollers, the distance can be limited to the distance required to open one pair of rollers 10. The short distance results in a small space requirement per phase, so that the overall dimensions of the power switch are significantly reduced, even if it has, for example, four or more parallel rollers. Another advantageous consequence of the short distance is the immediate distribution of current to the parallel rollers, and thus an increase in the rated current of the current switch and a decrease in resistive forces when the contacts are closed (resistive forces are electromagnetic forces generated when a large current is generated between two contacts). with).

The power switch is preferably provided with an even number of contacts, in pairs, to form pairs having one or more stepwise increasing dimensions.

·· Typically, four rollers are used, two large and · '. 25 two small ones whose absolute dimensions depend on it. : of the current at which the power switch is rated.

It is known to mount the movable contacts of a multi-pole power switch on a transversely displaceable contact bridge. According to the invention, the transfer distance is almost 30 times the distance between the center lines of two successive contact strips, the transfer length being necessary to move the contact bridge from the open position where the contact strips and the contact rails are sufficiently far apart to ensure power failure and avoid breakdowns. to position i 3 88084 ί - where all the contact rollers touch the touches.

Since the distance that the contact pin has to travel is shorter than previously known, the power switch and its housing size can be reduced. The mechanism that converts the hand-5 position to the translational displacement of the contact edge of the bending motion also becomes simpler.

According to the present invention, it is proposed to provide a power switch with contact rollers so that all contact rollers of the contact roller group have the same diameter, but that each pair is of different lengths, and that the two shortest rollers are placed closest to the contact rails and the longest rollers are located furthest from the contact rails. that the contact rails of the edges against the rollers 1 are stepped so that the progress of each step 15 corresponds to the length difference of the contact rollers, and that the distances between the opposite steps are so much longer than the corresponding contact rollers that there is a gap between the contact rollers and the contact rails. With the contact rollers 1a and 20 contact rails of the above type, the group of contact rollers moves a distance corresponding to the distance between the center line of the two rollers between each pair of rollers. However, care must be taken to ensure that the above-mentioned air gap is large enough to prevent punctures in the power switch.

In another embodiment, the distance between the individual contact rollers, measured perpendicular to the side surfaces of the contact rails, decreases stepwise so that the two rollers closest to the contact rails cooperating with themselves. are the furthest from each other, while the two rollers den which are furthest are closest to each other, and that the contact rail 1a has a correspondingly thin rail part along the edge facing the contact roller 1, the thickness of the rail part corresponding to the furthest - *. the distance between its pair of contact rollers and as it increases I .. '35 thereafter in steps corresponding to the distance between the contact rollers 4 88084. In this embodiment, all the contact strips are the same length. The contact surfaces provided between the contact rollers and the contact rails are larger than with the above-mentioned solution. The main object of the invention, 5 short travel, is also achieved. However, means must be provided to prevent the normally loaded spring rollers from coming into contact with the rails in the open position of the power switch. In this embodiment, it is also important that the array of contact rollers and contact rails 10 be formed so as to co-operate in direct contact in the closed position, but there must be an air gap between the rollers and rails in the open position at each point to avoid breakthroughs.

15 To further increase the power handling of the power switch, the division into several pairs of rollers can be extended to include a division into a main contact and a spark contact. With such a division, one or two rollers are selected as spark contacts, in which case this spark contact must always be closed first and 20 opened last. This is achieved by adjusting the position of the contact rollers or by adjusting the length and thickness of the step (s) of the contact rail in question. It is to be understood that this embodiment also includes: * the features of the present invention, i.e. that the rollers open contact with their parties simultaneously, as well as the associated advantages, especially a short travel distance. Preferably, the smallest or two smallest rollers are selected for spark contact-1, but You can also choose the largest and thus the strongest rollers, depending on the service options available at the on-site switch.

In a particularly preferred embodiment, a number of standard sizes are predetermined for the contact roller, these standard sizes corresponding to typical standard sizes of power switches. The size of the contact rollers thus given can be used as the largest contact roll with the current given in one power switch 5 88084, and as a "smaller" contact roll in the other power switch for a somewhat higher current. Thus, the number of different sizes of contact rollers to be kept in stock is reduced.

The invention is further explained in the following with reference to the accompanying drawings, in which:

Fig. 1 is a schematic side view of a group of contact rollers and two fixed busbars of the first embodiment in the open position; Fig. 2 shows a section along the line II-II of the contact group of the embodiment of Fig. 1;

Figure 2a shows an exploded view of the contact roller array of Figure 2;

Fig. 3 shows the same embodiment as Fig. 1. but in the closed position;

Fig. 4 schematically shows a view of an embodiment with four pairs of contact rollers; Fig. 5 shows a schematic view of a second embodiment of a group of contacts and contacts in the open position: Fig. 6 is another variation of the embodiment of Fig. 5;

Fig. 7 shows a schematic view of a third embodiment of a contact group with the contact rail in the open position;

Fig. 8 is an embodiment of Fig. 7 in the closed position; Fig. 9 shows an example of a detent in a spring-loaded group of contact rollers; 6 88084

Figure 10 shows an example of an alternative spring arrangement;

Fig. 11 shows an outline of a basic arrangement of a known power switch having a contact strip 11; and Figure 12 shows another example of a similar, known power switch arrangement.

The new circuit breaker has been developed for use in circuit breakers with three or four poles, e.g. in circuit breakers of a known type according to Figures 11 and 12, i.e. 10 circuit breakers with several busbars, in particular three or four busbars R. S, T and 0, having a switching function in three phases, and possibly also an O-connector, as indicated by reference to Figures 11 and 12. The four busbars may be located in planes parallel to each other, as shown in Figure 11, or parallel in the same plane, as shown in Figure 12. via the movable contact rollers 20 of the bridge 60, four busbars R, S, T and 0 are electrically connected to four respective busbars marked R ', S', T1 and 0 'on the other side of the contact bus. The contact bridge 60 can be shaped in many different ways, and in the drawing it is outlined only by a dotted line, and the double arrow 1a indicates the direction of movement. The transfer mechanism is not shown, but may be implemented in a number of ways known to those skilled in the art, and may be manual power switching by rotating or turning the lever, whereby the movement of the switch is transmitted to the translational displacement of the coke cassette 60 by a transfer mechanism. The power switch can also be arranged to open or close automatically.

For the sake of clarity, only two contact rollers are shown in front of each busbar in the drawing, as it is taken for granted that there are, of course, two corresponding rollers behind the power switch 7 88084. Depending on the rated current, different numbers of contact roller pairs can be used. When opening and closing the power switch, the movement of the contact pin must be so long that all 5 contact rollers become detached from the contact rail. As a result, the power switch housing must be large enough to allow the necessary travel. The long travel associated with multiple contact rollers brings with it a complex transfer mechanism and increases the time that elapses between the opening and closing of the opening or closing, respectively.

A new contact roller assembly for the multi-pole power switch described above will be described below, with the following figures showing various examples of embodiments of the contact roller assembly 15 and its rails. It will be appreciated, however, that a new type of contact roller can, of course, also be used in a power switch with one or two poles.

The first embodiment 20 shown in Figures 1-3 uses a contact roller assembly 20 having four rollers 21, 22, 23, 24, the rollers in pairs forming pairs, each with the same diameter but different: · length, L, 1, with two rollers 21 , 22 is closest to the fixed contacts 25 and 26, and these pairs of forming rollers are shorter than the other two rollers.

Correspondingly, the fixed contacts 25 and. 26 is a recess for the smallest pair of contact rollers 21, 22 which fits into the recess without touching the fixed contacts before the large contact rollers contact the fixed contacts. As shown in Figure 1, the recess is made precisely deep enough for both pairs of contacts to contact the fixed contacts to their parties simultaneously. In this case, simultaneity is understood as. about 5 ms interval, i.e. 50 Hz same quarter wave.

35 As will be apparent to one skilled in the art, the exact 8 88084 concurrency is impossible, and thus in the above embodiment it is impossible to immediately determine which contact roller first closes or opens the circuit. In a modification of the embodiment of Figures 1-3, it is therefore proposed that the recess shown be slightly reduced so that the smallest pair of contacts 21, 22 makes contact first and disconnects it last. This pair of contacts thus forms a spark contact, the contact pair 23, 24 forming a so-called main contact. In this embodiment, it is advantageous to make the spark contacts 21, 22, and possibly the part in contact with the spark contact, of a material more resistant to the fixed contact than ordinary copper, and / or to apply a special surface treatment to it to withstand the sparks applied to the spark contact. The recess described in the alternative embodiment is slightly deeper in that the pair of contacts 23, 24 form a spark contact. It should be emphasized in this connection that in the proposed embodiment the difference in the closing moments is very small, but in principle it is nevertheless true that the described contact rollers close approximately simultaneously. Figure 3 shows the position of the contacts in the closed position. A comparison of Figures 1 and 3 it is apparent that the path length of the contact assembly in the open position to the closed: January 25 position corresponds to the length of the arrow in Figure 1. The travel distance mainly corresponds to the distance required to close one: the contact of the roller, and this applies regardless of the number of rollers.

The contact rollers shown can be mounted in a number of known ways, e.g. as shown in Danish patent 142,254, or, as illustrated in Figures 5. 6 and 7, in a stop 50 with one or more springs F. which press the contact rollers into a suitable contact to ensure pressure when the contact rollers slide into place on either side of the corresponding fixed contact rail. Selecting suitably strong springs ensures · 9 88084 sufficient contact pressure. It may be advantageous to adjust the force of the spring according to the dimensions of the contact roller in question.

An example of a possible embodiment of the contact roller assembly is shown in Figures 2 and 2a. This group of contact rollers comprises on its sides a T-shaped iron body 27, a spring washer 28a having a corresponding mating piece 28b, and four contact rollers 21, 22, 23, 24 which partially rest on the spring washers 28a and 29b and are partially held together by the locking pieces 29a and 29b. There is a spacer 19 between the rollers 21, 24 and 22, 23 and their locking pieces 29a and 29b, the thickness of which corresponds to the thickness of the contact rail. All portions 28a, 29a, 19, 29b and 28b have an elongate slot through which the foot of the T-shaped iron piece 27 can pass. Above the last spring washer 28b there is a coil spring and the whole arrangement is held together by a locking plate 17 which is arranged to be pressed down on the T-shaped leg and then turned by about 90 °. The central spacer 19 is further provided with extensions 19a which co-operate with means of a movable contact bridge arranged for this purpose to lock the contact roller group on the contact bridge means provided for this purpose (prior art). You touch an inrul lien group. : can be adapted in many different ways, and the above is. · .. just one example of the embodiment.

Figure 4 shows a contact group arranged the same. . according to the principle, but with four pairs of tangential rollers and four steps. As can be seen from the figure, ‘this type of contact can be equipped according to needs: a different number of contact rollers. Also in the case of four contact rollers, the necessary travel of the contact bridge from the closed position to the open position corresponds to only one, by one; or the travel of a contact group with two rollers. In this embodiment, it is also possible to select one of the rollers to act as a spark contact.

10 88084

In another embodiment, the rollers have different diameters, as illustrated in Figure 5. In this embodiment, the lengths of the rollers may be equal or staggered. The diameters of the rollers 31 and 32 are small d, while the diameters of the rollers 33 and 34 are larger D. Correspondingly, the fixed contact is relatively thin along the outer edge near the movable contact member, so that the small contact rollers 31 and 32 slide in the close thin portion 35 of the fixed contact. across without touching 10, after which the small contact rollers 31 and 32 contact the thick part 37 approximately simultaneously as the two large rollers 33, 34 contact the thin part 35. In this embodiment it is also possible to select one contact pair to act as a spark pair and adjust the dimensions 15 so that this contact pair switches on first and switches off last. In this case, however, only small dimensional changes are involved, so that it still applies that the contacts touch their parties simultaneously.

In the example of Figure 6, the smallest contact rollers 31 ', 32' 20 are arranged to contact the thin part of the rails 35, while the large contact rollers 33 ', 34' contact the thick part 37 of the rails. Since in one pair of contacts, e.g. 31 and *: 32, parallel rollers - the electromagnetic forces are proportional to the length of the contact rollers and inversely proportional to their mutual distance (corresponding to the length and / or width of the air gap), it may be advantageous to use separate spring loads for each pair of rollers, as proposed in Figure 6, or for each roll, as is suggested in Fig. 30 5. In the embodiment of Fig. 6, the thick portions of the rails 37 may be coated with a more durable material, thereby making the rails spark resistant. In this case, the rollers 33 'and 34' are likewise made of a spark-resistant material.

11 88084

Figures 7 and 8 show a variant in which the contact rollers 11a used have the same diameter, but in which they are mounted at different distances from each other. Thus, in principle, the same effect is achieved as with the arrangement of Figures 5 and 6. The rollers 41 and 42 are farther apart than the rollers 43 and 44, respectively, and the fixed contact 46 is provided with a group of steps so that the four contact rollers open simultaneously as they are pulled out of the fixed contact. Also in this case, it is possible to define one or two rollers as a spark contact and to make them, and possibly the corresponding part of the rail, of a special spark-resistant material. It will be appreciated that the arrangement shown may be extended to include six, eight or more rolls.

In the embodiments of Figures 5, 6 and 7, it is important that the retainer 50 be shaped to maintain a predetermined minimum distance between the contact rollers in each pair of contact rollers in the open position. It will be apparent to one skilled in the art that this will be accomplished in a number of different ways. An example of a possible embodiment 20 is shown in Fig. 9, which shows a section of a stop in which the guide rollers are arranged in the form of an elongate hole 51 as well as support surfaces and possibly guides for compression springs pressing the rollers against each other.

It should be emphasized that within the scope of the invention it is also possible to provide a detent with tension springs, as e.g. suggested in Figure 10, in which two springs 53 and 56 pull the roller 21 downwards and two other tension springs 54 and 55 pull the roller 22 up. 57 and 58 are 30 partition walls provided with an elongate guide for the contact roller, as shown in Fig. 9.

• · i2 88084 The present invention can be modified in many ways. Thus, within the scope of the invention, it is possible to vary one or more parameters, roller length, diameter, distance and spring pressure in the same group of contact rollers.

Claims (8)

13 88084 A power switch having a plurality of movable contact members (20) and a corresponding plurality of fixed contact members (25, 26), wherein the at least one contact member comprises a spring-loaded array of contact rollers (20), the plurality of rollers (21, 22, 23, 24 ) is adapted to contact the flat side surfaces of the two contact rails (25, 26) between the rollers, and whereby the rollers can slide or rotate on said side surfaces when closing or opening the power switch, 10 characterized in that the group of contact rollers (20) and the contact rails (25) cooperating therewith 26) arranged to form a stepped connection. A power switch according to claim 1 and of the type in which the movable contacts are mounted on a translationally movable contact (60), characterized in that the length of the transfer is almost equal to the distance between the center lines of two successive contact rollers, the transfer the length is necessary to move the contact bridge from the open position - where the contact rollers 20 and the contact rails are located at a sufficient distance from each other to ensure power failure and to avoid breakdowns - to the closed position - where all: the contact rollers contact the contact rails. » Power switch according to Claim 1 or 2, characterized in that all the contact rollers 11a (21, 22, 23, 24) of the group of contact rollers (20) have the same diameter, but in that each pair has a different length (L, 1). , and that the two shortest rollers are placed closest to the contact rails (25, 26), that the longest rollers are placed away from the contact rails (25, 26), that the contact rails of the edges opposite the contact rollers are staggered so that the progress of each step corresponds to the length of the contact rollers and that the distances between the opposite steps: are so much longer than the corresponding contact rollers, that there is a gap of 1 «88084 everywhere in the open position. Power switch according to Claim 1 or 2, characterized in that the distance 5 between the individual contact rollers, measured perpendicular to the side surfaces of the contact rails, decreases stepwise so that the two rollers (31, 32 and 41, 42) which are closest to the co-operating ones the contact rails (37, 46) are furthest apart, while the two rollers 10 furthest are closest to each other, and that the contact rails have a correspondingly thin rail portion (35, 45) along the edge facing the contact rollers , the thickness of the rail part corresponding to the distance between the farthest pair of contact rollers (33, 34, 43, 44) and increasing thereafter 15 steps corresponding to the distance of the contact rollers. Power switch according to Claim 4, characterized in that the diameters of the contact rollers decrease in pairs in steps. 20 Power switch according to Claim 5, characterized in that all the contact rollers are of equal length. Y 25 current switch according to one or more of Claims 1 to 6, characterized in that the stepped contact is supported separately or in pairs by a stepped spring load for each roll or pair of rollers. Power switch according to one or more of the preceding claims, characterized in that the contact group ... is divided into at least one main contact and at least one spark contact, and in that the spark contact and / or the corresponding contact rail part is either made of a highly spark-resistant material or surface-treated lasts-35 intervals with coating. i 15 88084