BG63836B1 - Step switch - Google Patents

Abstract

The invention relates to a step switch. Two vacuum switchgear cells (34, 35) are provided as electrical switching means. The fixed selector contacts (n) are arranged alternately in parallel strips and are interconnectedy means of two moveable mechanical contacts (8, 9) existing in a fixed relationship to each other. A mechanical changeover contact (28) is actuated by means of an energy storage mechanism that is triggered after a prior lifting movement and both vacuum switchgear cells (34, 35) for each phase are simultaneously actuated.

Description

Technical field

The invention relates to a step switch for continuous interruption between different deviations of the winding of a step transformer.

BACKGROUND OF THE INVENTION

The step switches are used to adjust the voltage, active power and reactive power of the power grids by changing the transform factor under load. In the case of the single-phase stepper switch known from WO94 / 02955, the fixed stepping contacts, which are always electrically connected to one deflection of the step of the step transformer, are mounted vertically in a single line. In addition, two separate linearly moving selective contacts are provided which surround the fixed selective contacts independently of one another. The actuation of the movable selector contacts at the known step switch is performed by means of a drive mechanism consisting essentially of a pull-out carriage, with the possibility of continuous drive, and of a drive section which can be lifted by a spring energy accumulator. After actuation of the spring energy accumulator, the actuated part follows in a jumble the previous continuous movement of the pull-out sled. One of the movable selector contacts is rigidly mounted on the removable carriage and the other movable selector contact is located on the actuated part. At least two, usually three, vacuum switching chambers which together with at least one switchable resistor are provided with this known single-stage switch. are fixed to the actuated part and thus perform its jumble movement after actuation.

DE 4216034 C1 discloses another step switch which also has fixed selector contacts mounted in a guide and movable contacts that are mounted in a housing and need only one actuator. This step switch is a single-phase construction, i.e. The corpus bar encloses all the structural parts that are required to switch one phase and form the so-called single-phase step-switch module. For three-phase construction, three such step-switch modules and then three separate enclosures must be used.

The known step switches are suitable in themselves for the realization of large power switches and find application in large batches of products. For simpler applications, only at low system voltages and power switches, they are too complex. First of all, it should be borne in mind that the known step switch is a single-phase module. For ordinary three-phase use, three such complete step switches must work together, and also three complete actuators, energy accumulators and three actuators are required. The driving part of the known stepped switch, which performs a steep vertical movement at each switch, due to the many structural details that are attached to it, has considerable mass. As a consequence, expensive means of damping the movement as well as balancing the forces of gravity are required. Synchronous actuation of the individual vacuum switching chambers during the switching sequence also requires relatively sophisticated high precision actuators.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a switch of the type indicated, which has a simple and reliable construction and, when using only two vacuum chambers as electrical switching means, enables secure power switching in the lower and middle switching capacities up to step voltages in the order of about 500 V.

The problem is solved by a step switch with the features of the first patent claim. The dependent claims relate to particularly advantageous embodiments of the invention.

Useful in the step switch according to the invention is a simple and reliable construction. The mechanical as well as the electronic switching means for all the switched phases are assembled into a single housing. Thus, only one actuator is required for all phases. There is only one energy accumulator and all vacuum chambers of all phases, as well as all mechanical switching contacts are mounted on a single base plate. The foot switch according to the invention has only small movable masses, which is why it is made clear that conventional structural parts are fixed and the motions need not be made with movable selective contacts. An additional advantage of the step switch according to the invention is that the two movable selector contacts are no longer actuated independently, but are fixed together and invariably in their relative position relative to each other. This simplifies the overall mechanical construction further and also makes it possible to save space on site.

According to a particularly advantageous embodiment of the invention, actuation of these movable contacts is accomplished in a particularly simple manner by a linear Maltese segment or by two such Maltese segments. From US-PS 3673364 and 3824355 it is known to move movable contacts along a guide rail through a rack. However, the known solutions do not refer to a load-operated step switch, but to a load-switched deflection switch (deenergized deflection switch). Another difference in this embodiment of the step switch according to the invention is that the known gears are actuated by a permanently glued gear wheel. The Maltese segment of the described embodiment of the step switch according to the invention is driven by a Maltese actuator which, in a certain position, engages. The solution with the Maltese segment allows for a particularly simple rotational motion of the drive motor, respectively. of the drive shaft to be temporarily transformed into displaced longitudinal idling, thus known solutions with their rigid connection between the drive and drive parts are generally not appropriate. According to another particularly advantageous embodiment, the two movable selector contacts of each phase are mounted together motionlessly on a support frame in such a way that the support frame of the Maltese segment described can move.

An explanation of the attached figures

The invention is further explained by the following figures:

Figure 1 shows a step switch according to the invention in a schematic view, front view;

Figure 2 is a partial view of the base plate of the foot switch, rear view;

Figure 2a is also an image in which, for clarity of assembly, the additional roller guidance clarified is omitted;

Figure 3 is a partial view of the base plate of this foot switch in front view;

Figure 4 is a schematic representation of the interaction of fixed electoral contacts and mobile contacts;

Figure 5 is a detailed wiring diagram on which the step switch according to the invention is based;

Figure 6 shows the switching sequence when switching from the deviation of the coil n-2 to the deviation of the coil n-1.

Examples of carrying out the invention

In the beginning, the basic construction of the step switch according to the invention should be clarified by means of Figure 1. The whole apparatus is housed in a housing having a rear, electrically insulated housing plate 2. In the rear housing plate 2, three contact pins are attached in parallel 3 of insulating material carrying fixed selective contacts 4. In this case, one contact carrier 3 is provided for a single phase. The individual contact supports 3 are mounted parallel to each other and the separate stationary selector contacts 4 for each of the three phases are mounted in the same way. As can be seen from the figure, the individual fixed selector contacts 4 are always arranged alternately spaced relative to each other on the left and right side of the contact carrier 3. The switching of the fixed selector contacts 4 is further explained below. The side walls of the housing 1 are provided with longitudinal guides 5 in which the Maltese segment 6 is guided, with the possibility of vertical displacement. A support frame of insulating material 7 is attached between the two side Maltese segments 6, which for each phase carries two movable contacts 8,9. The movable contacts 8, 9 of each phase always correspond to the fixed contacts 4 of the respective phase. By longitudinal displacement of the Maltese segments, the bisector of the supporting frame 7 internally of the longitudinal guides 5, the movable contacts 8, 9 may switch various fixed selective contacts 4. The movable contacts 8, 9 are so dimensioned in their longitudinal extension that in their entire motion at each switching step always reaches a new stationary contact without the other one leaving the previous stationary selective contact. This is illustrated one more time in Figure 4: a) the position before moving the support frame Ί is shown, and thus the movable contacts 8.9 c) the position is shown after one fully completed switching step. To the figure 1 laterally in the housing 1 is provided a drive motor 10 in the attachment 11 and connected to the gear 12. From this gear 12 comes the first drive shaft 13 of insulating material, which penetrates the housing horizontally and is camped at the other end in bearing 15. In the two ends of the drive shaft 13 have respectively a Maltese drive element 16 corresponding to the corresponding Maltese segment 6. The gear 12 is mounted such that, at each switch, whereby the motor 10 is driven, the first drive shaft 13 performs a 360 ° rotation. The two Maltese actuators 16 are engaged in the respective Maltese segments 6 and are displaced by the carrier frame 7, which is fixed between them, in a definite upward movement, respectively. down, depending on the direction of rotation and therefore on the direction of switching of the foot switch. By shifting the support frame 7 upwards, respectively. down, the two movable contacts 8.9 are driven in each phase together upwards or respectively. down. In this case, one of these movable contacts, as has already been explained, leaves the former stationary selective contact to which it belongs and contacts another fixed selective contact 4, while the corresponding other movable contact is also displaced by its longitudinal dimension, but does not remain still in contact with the current stationary selective contact 4. With their free ends, the movable contacts 8, 9 slide respectively on parallel to each other electrically conductive contact guides 17, 18 of each phase, which m turn are respectively electrically connected to a first fixed contact 25, respectively. one second fixed contact 26. This will be explained below. The individual contact guides 17,18 are fixed spatially in the housing 1 by means of the traverse 52. In addition to the first drive shaft 13 already described, the second drive shaft 14 also extends and extends vertically upwards in the housing. This second drive shaft 14 performs a 180 ° rotation at each switch and is connected to a drawable carriage 19 of an energy accumulator. The energy accumulator possesses as essential structural parts precisely that pull-out carriage 19, which by the second drive shaft 14 is tensioned against the force of the spring of the energy accumulator 20, as well as an additional drive-piece 21, which, after actuation, follows the longitudinal movement of the carriageway 19. Such accumulators in which one pullable sled moves by rotating a shaft in a longitudinal direction, thereby tensioning, and in which the actuated part, after actuation, also extends but movement is in principle already known, so more details will not be described here. Energy accumulators of this type are extensively described in DE-PS 2806282 or also in DE-PS 3919596. The actuated part 21 is connected to a driven link 22, which transmits the longitudinal horizontal longitudinal motion after acting on an actuating carriage 23 of an insulating material. The function of the actuating carriage 23 is further clarified below. Attention should be paid once again to the base plate 24 of the electrically insulated material mounted in the housing 1, for which, for each phase, one first fixed contact 25 and one second fixed contact 26 and one fixed main contact 27 are provided. this, in the bearing element 29, is mounted a movable switch contact 28 having a contact member 31 through which one of the two fixed contacts 25, 26 can always be electrically connected to the main contact 27. This lever structure has the function of electric Eski switch. The movable switch contact 28 has in its upper part an actuating groove 32 which can be actuated by an actuating part 30 with a actuating spike 33 secured in the actuating carriage 23. In horizontal motion of the actuating carriage 23, after actuation of the actuated part 21 of the energy accumulator , the actuating spike 33 engages in the actuating groove 32 and rotates the entire movable switch contact 28 around its bearing member 29, thereby switching between the electrical connection of one of the two fixed contacts 25, 26, as well as the main contact 27. In the rear, facing to the back plate of the housing 2 side of the base plate 24, two structural elements are attached, which now need to be clarified with the help of Figures 2, 2a and 3. Two vacuum switching chambers 34, 35 are attached to the main plate 24, first of all, for each phase via fastening brackets 36. In addition, a switching resistor 49 is mounted in the lower portion of the main plate 24. sliders 50,51 of the two vacuum switching chambers 34, 35 are provided respectively with one swinging actuating arm 38, 39. Each actuating arm 38, 39 has at its free end respectively one roller 40, 41. With respect to sacred geometry, the actuating arms 38, 39 are formed such that the two rollers 40, 41 of each phase are arranged one on top of the other in one vertical line. The two rollers 40, 41 roll accordingly into one contour

43,44 of roller guide 42, which for each phase is secured in the actuating carriage 23. The roller guide 42 has a second additional loop 53 in which an additional roller 54 is guided. The additional roller 54 is attached directly to the base plate 24 and guides the actuator. carriage 23 in its horizontal motion after actuation of the energy accumulator. In addition, a locking plate 23 of a sheet 47 is fitted to the actuating carriage 23 with one common longitudinal guide 48 for each phase in which both the rollers 40, 41 are also guided. This actuating arm 47 is provided with the actuating arms 38, 39 actually move vertically when the actuating carriage 23 is displaced and thus the roller guide 24 with its contours 43, 44, thus actuating the actuating sliders 50,51 of the vacuum switching chambers 34,35, but cannot be divert laterally. This retaining plate 47 is mounted between the roller guide 42 and the actuating sleeve 23. In the image of Figure 2, this is concealed by the roller guide 42, in figure 2a the roller guide 42 is omitted. The two rollers 40,41 are in each case so sized that they simultaneously roll in one of the contours 43, 44 and additionally in the longitudinal guide 48. In a known manner, for the alignment of the contact slopes, springs 50,51 are still provided in the drive sliders 50,51. 45, 46.

Further, the function of the structural details described should be clarified once more as they switch into their interaction. To initiate a power switch from respectively one stationary selector contact 4 to one adjacent other selector contact, the electric drive motor 10 is actuated which, through the gear unit, makes two motions of the two drive shafts 13.14 independently of one another. The rotation of each of the two drive shafts 13.14 thus depends on the direction of the power switching, i.e. whether a switch is executed in the high direction or the low direction. The first drive shaft 13 performs a 360 ° rotation at each power switch, after a certain rotation angle engages the two Maltese drive elements 16 in the respective Maltese segments 6 and displaces the supporting frame 7 and thus the movable contacts 8, 9 such that one from the two movable contacts the new fixed selective contact is reached. In addition, the gear 12 provides for a known, non-represented, free-running, freewheel of the first drive shaft 13, which ensures that when the direction of change is reversed, and thus the direction of rotation of the drive shafts, the first drive shaft 13 is turned. , and thus the Maltese drive element 16 is rotated not by a full 360 ° but by a small angle in such a way that the Maltese drive element 16 is not engaged in the Maltese segment 6 and is thus not realized movement of movable co pins 8,9. This common principle for step-switches can also be clarified by means of Figures 4 and 6. When first turning the direction of switching, the movable contacts 8, 9 remain on the respective selective contacts which they just contact, while through the second drive shaft 14, performs tensioning of the energy accumulator and after its activation the movable switching contacts 28 and of the vacuum switching chambers 34,35 are actuated. In the case of multiple switching in the same direction, the described freewheel does not work and the initially movable contacts 8, 9 are brought to their new position before the mechanical and electrical switching means are activated again after the release of the energy accumulator. At the same time, the second drive shaft 14 rotates 180 ° and pulls the pull-out carriage 19. After full tension, the driven part 21 is released in a horizontal direction with the thumb not shown in detail. The movement is always performed alternately, once to the right and to the next switching □ to the left, etc., which is due to the fact that the actuated part always moves to the left after the release, respectively. right end position. The corresponding horizontal movement of the drive portion 21 through the drive link 22 is transmitted to the drive carriage 23, which also alternately bounces once to the right and to the next switch once to the left. This actuates both the mechanical switching elements on the front of the base plate 24 and the vacuum switching chambers 34, 35 on the reverse side of the base plate 24. On the front of the base plate 24, the corresponding actuating spike 33 is engaged in the actuating groove 32 and rotates the movable switching contact 28, which thus interrupts the electrical connection from the first fixed contact 25 to the main contact 27 and more precisely connects the second fixed contact 26 to the main contact instead. 27 tact and vice versa. As already explained, the two fixed contacts 25, 26 through the two contact rails 17, 18 are respectively electrically connected to the actual contacting the movable contacts 8, 9 by a fixed selective contact 4 in such a way that by activating the movable switching contacts 28 performs switching from one movable contact 8 to another movable contact 9 and thus from the present contacting stationary selective contact to the new stationary election contact. On the opposite side of the base plate 24, a roller guide 42 is actuated, which also moves further through which the contours 43, 44 are displaced therein, in which the rollers 40, 41 of the actuating arms 38, 39, respectively, are guided. vacuum switching chambers. By the corresponding geometric layout of the contours 43, 44, more precisely by their horizontal displacement, the firing sequences are defined precisely. The additionally explained retaining plate 47 with its longitudinal guidance 48 prevents an unwanted lateral displacement of the rollers 40, 41 and thus of the entire actuating arms 38,39. In the figures, the electrical connections between the individual components described are not shown in each case. Figure 1 shows only the contact guides 17, 18 of each phase, which are electrically connected to the respective movable contact 8, 9 and on their side to one of the two fixed contacts 25, 26, respectively. The electrical connecting wires to the fixed selector contacts 4, to the vacuum switchgear 34, 35, to the fixed contacts 25, 26, the main contact 27 and to the load section are not shown for reasons of transparency.

The electrical connection between the individual components described can be seen in full from Figure 5.

Finally, Figure 6, using the scheme of Figure 5, once again describes an exemplary power switch from n-2 to η-l, in particular the sequence of actuation of the individual components one after the other. The corresponding conductive parts of the circuit are marked with thick lines. As the arrangement of the structural members corresponds exactly to Figure 5, for reasons of transparency in Figure 6, the positions are not indicated. Power switching consists of the following switching steps, one after the other:

a) shows the starting position in which the fixed contact n-2 is switched on. In this position, the movable switching contact 28 connects the first fixed contact 25 with the main contact 27 and through the closed first vacuum switching chamber 34 establishes a connection to the load deflection L. The second vacuum switching chamber 35 is open

c) the movable contacts 8, 9 are actuated together; the movable contact 8 remains on the fixed selector contact n-2, and the movable contact 9 has reached the new fixed selective switch contact η-l. This is shown in Figure 4; a change in the presentation scheme compared to (a) has not yet been established

c) the second vacuum switching chamber 35 is closed, some of the load current is now flowing in addition through the switching resistor 49

d) the first vacuum switching chamber 34 is opened, all the load current flows through the switching resistor 49 and the second vacuum switching chamber 35

e) the movable switching contact 28 rotates and connects the second fixed contact 26 to the main contact 27, the first vacuum switching chamber 34 closes and absorbs the load current, further equalizing current flows

g) the second vacuum switching chamber 35 reopens, now the load current flows from the new fixed selector contact η-l through the first vacuum switching chamber 34 to the load deflection L; The new stationary position has been reached and the load switching is complete.

The invention is explained by a three-stage step switch. Within the scope of the invention, it is also possible to provide for a single-phase stepped switch for which only one of the previously described separate structural assemblies, consisting of fixed selective contacts 4, movable contacts 8, 9, switch 25, 26,27, is provided. , 28 and two vacuum switching chambers 34.35. This does not change the type and manner of actuation of the individual structural elements through the first and second drive shaft 13.14 in the switching and switching sequence.

Claims (10)

1. A stepping switch for continuous switching between different deviations of the winding of a step transformer, wherein fixed selective contacts connected electrically to the individual deviations of the winding are mounted longitudinally in lines, whereby as an electrical switching means for each of the switched phases vacuum switching chambers, which provides propulsion, which is always actuated when the foot switch is actuated, and wherein an energy accumulator is provided pallet, which is actuated by the actuator and is actuated after the actuation of the electrical switching means, characterized in that for all switched phases the fixed selective contacts (4), the movable contacts (8,9), the two vacuum switching chambers (34, 35), all additional switching and actuating means, as well as the separate actuator (10), as well as the separate energy accumulator, are mounted in one common housing (1) that the fixed selector contacts (4) of each phase are alternately mounted in two parallel e.g. claiming that the two movable contacts (8,9) of each phase can be actuated together and invariably in their relative position relative to each other, that each of the two movable contacts (8, 9) of each phase corresponds to mounting respectively in one guide fixed selective contacts (4) that each of the two movable contacts (8,9) of each phase is electrically connected to one mechanical fixed contact (25, 26) of an electrical switch whose main contact (27) is through a first vacuum switching chamber (34) is related to one load tklonenie (L) and that one of the two movable contacts (8) further in a sequential circuit of a switchable resistor (49) and a second vacuum switching chamber (35) is also connected with the load shunt (L). Step switch according to claim 1, characterized in that the separate actuator (10) outputs one first drive shaft (13) and one second drive shaft (14) that all the movable contacts (9,10) of all the switching phases are actuated together continuously by the first drive shaft (13) that the pull-out sleeve of the energy accumulator is actuated by the second drive shaft (14), whose drive part (21) is actuated in a predetermined switching sequence by all switches consisting of two correspondingly ne movable contacts (25, 26), main contact (27) and one movable switch contact (28) and all vacuum switching chambers (34, 35) of each of the switching phases. Step switch according to claim 2, characterized in that all the movable contacts (8,9) are mounted fixedly on a common support frame (7), so that the rigid support frame (7) is arranged to be displaced in such a way that the fixed selector contacts (4) are capable of being re-crawled from the movable contacts (8,9) and that the rigid support frame (7) is connected on both sides to one Maltese segment (6), respectively, and that the first drive the shaft has two Maltese drive elements (16) which always correspond of one of the Maltese segments (6) in such a way that by rotating the first drive shaft (13) the supporting frame (7), and thus the movable contacts (8,9), are capable of moving a particular switching step vertically up or down. Step switch according to claim 2 or 3, characterized in that a housing plate (24) is provided in the housing (1) in which, on its front side, there is for each switch phase a switch consisting of two fixed contacts (25, 26), the main contact (27) and one movable switch contact (28) and which carries on its back side for each phase two vacuum switch chambers (34,35) that the actuated part (21) with its hopping motion after actuation is coupled to the next actuator (23) and, h actuating slide (23) on its front side carries means for actuating the movable switch contacts (28) and on its back side carries means for activating the vacuum switching chambers (34,35). Step switch according to claim 4, characterized in that the means for actuating the movable switch contacts (28) consist of one actuating part (30) with actuating spike (33), the latter always engaging in actuating groove ( 32) of the bearings capable of rotating around the bearing element (29) of the switch contact (28). Step switch according to claim 4 or 5, characterized in that the means for activating the vacuum switching chambers (34,35) consist always of one roller guide (42), that each of these roller guides (42) has two contours (43, 44) in which one roll (40, 41) is always driven and that each roll (40, 41) always acts through one actuating arm (38,39) on one actuating slider (50,51). vacuum switching chamber (34, 35) Step switch according to claim 4 or 5 or 6, characterized in that the two rolls (40, 41) of each phase are additionally always guided in one another by a vertical guide (48) on a sheet of retaining plate (47) secured to the actuating carriage (23) in such a way that they are fixed to one another in their upright position. Step switch according to one of the preceding claims, characterized in that the electrical connection between the respective movable contacts (8,9) and the corresponding fixed contacts (25,26) of the respective switches is always performed by means of electrically conductive contact guides (17, 18) in such a way that the movable contacts (8, 9) always slide with one free end on one of the contact guides (17,18), more precisely connected electrically. Foot switch according to one of the preceding claims, characterized in that the movable contacts (8,9) are so dimensioned in their longitudinal extension in the direction of travel that, when they are moved together, at each switching step, one of them it always reaches one new stationary polling contact (4) without the other one leaving the former stationary polling station (4). 10. A switch according to any one of claims 6 to 9, characterized in that additional means are provided for horizontally directing the actuating carriage (23) in such a way that the roller guide (42) connected to the actuating carriage (23) has an additional horizontal contour (53) in which an additional roll (54) is guided that is firmly connected to the base plate (24).