BG113484A - Three-phase step voltage regulator with stacked phases - Google Patents

Abstract

The three-phase step voltage regulator has an oil pan consisting of a bearing head (1) with a flange (2) and cover (3), an insulating cylinder (4) and a bottom (5). A removable part is located in the oil pan, carried by a flange (7), to which a metal sleeve (8) with a disc (41) is attached. A column of three fully mounted single-phase power switches (A, B, C) is mounted to it, interconnected by insulating cylinders (42). On the metal bushing (8) is a bearing of rolling bearings even profiled bushing with a gear ring (16) connected to an even arm (48) carrying an insulating column (50) with contact bridges (54) which successively contact with even fixed contact elements (55). At the lower end of the profile bushing (16) is a rolling bearing odd profile bushing with a gear ring (17) connected to an odd arm (49) carrying an insulating column (53) with odd contact bridges (58) which are connected in series with odd fixed contact elements (59). A spring energy accumulator (9) is installed on the supporting flange (7), directly connected by a shaft (37) to the shafts of the power switches (A, B, C). A worm gear with mechanisms (14) is mounted on the cover (3), which drives a small gear (12) and a large gear (11), which through the rod (10) charges the spring energy accumulator (9) and with its shaft rotates a double a translation (22) which alternately rotates an even block (18) and an odd block (21), each integrally engaged with the toothed rings of the bushings (16, 17). The shaft (29) driving preselector is connected by rods (34), shaft (26) and two-position Maltese sector (27) to a drive disk (30) with a roller mounted on the odd profile sleeve (17). The preselector is composed of an insulating half-cylinder (63) with an insulating column (67) and contact bridges (66) contacting fixed contact elements (64, 65).

Description

THREE-PHASE STEP-BY-STEP VOLTAGE REGULATOR WITH STACKED PHASES

FIELD OF ENGINEERING

The invention relates to a three-phase step voltage regulator, which is built into power transformers with the task of regulating their voltage under load. One type of tap-changer consists of a power switch located in an oil pan, under which a selector with a pre-selector is mounted. Another type is the column step regulators, where the three phases are arranged in a tier in an oil pan. Column step regulators are divided into two design concepts. The first is the load-selected, where the selection and switching are performed by the same contact system. In the second case, three single-phase power switches are arranged in a row in the middle of an oil tank, and around them are located the contact systems of the selected one. The invention relates to this group of step voltage regulators.

PRIOR ART

A step voltage regulator (1) containing a bearing head, an insulating cylinder and a bottom is known. A spring energy accumulator, a toothed differential mechanism and a Maltese gear are established in the bearing head. In the center of the isolation cylinder is a smaller isolation cylinder in which three single-phase power switches are arranged. Each power switch has one even movable and radially directed current carrying contact element with contact roller at the end, one odd contact element with contact roller and one current carrying contact element with contact roller. On the inner surface of the bearing insulating cylinder, five even arc-shaped fixed contacts, five odd fixed contacts and a current-carrying ring are mounted on each floor. The inner insulating cylinder with the power switches is rotated periodically at an angle of 36° from

The 1/11 Maltese gear and contact rollers contact in a certain sequence with the fixed contact elements and the contact ring. Actuation of the Maltese gear and spring energy accumulator is accomplished by a known worm gear. The job of the gear differential is to synchronize the selection and power shifting.

A disadvantage of this step voltage regulator is that due to the front contact of the contact rolls with the fixed contact elements, the permissible nominal current is limited, due to the reduced thermodynamic resistance and increased overheating. Another disadvantage is that the mechanisms located in the bearing head are of great complexity. A disadvantage is that it is difficult to insert the column with the power switches and remove it. Contact rollers are arc-shaped and mounted on vertical axes. To ensure contact failure, the radius of the face of the contact rollers is several millimeters larger than that of the faces of the contact arcs. During assembly and disassembly of the removable part, repeated impacts occur between the rollers and the arches, which injures them. This can aggravate contact with possible unpleasant consequences during operation.

Another stepped voltage regulator (2) is known, in which the column with the three tiered single-phase power switches is mounted in a fixed oil pan by means of plug contacts. For each of the three phases, an even conductor ring, an odd conductor ring, and a terminal conductor ring are stacked on the outside of the insulating cylinder of the oil pan. The rings are contacted by T-shaped movable contact plates, which with their outer arc are periodically connected to fixed contact elements mounted in layers on segments cut from an insulating cylinder. The T-shaped contact elements are attached to an insulating segment connected in its upper part with a large gear wheel bearing on the insulating cylinder, and in its lower part - to a bearing ring. The large pinion is actuated by a block of small pinion and worm gear connected to a double translation. It is rotated 180° in one shift by a gear meshed with a smaller gear making one revolution per shift connected to a worm gear. A spring-energy accumulator is actuated by the gear wheel performing half a revolution of switching through the rod.

A disadvantage of this step voltage regulator is that it has a complicated design with increased overall dimensions, weight and cost. A disadvantage is that the large gear and the bearing

2/11 rings are located at the upper and lower ends of the isolation cylinder by sliding bearings, which is a prerequisite for crossing and possible jamming. Another disadvantage is that the power switches contact the inner surface of the oil pan through plug contacts, which limits the rated current, although the external contact plates have greater capabilities.

Another known step voltage regulator (3) has a single-shaft version and a two-shaft version. In the single-shaft version, one Maltese wheel with double translation is used, and in the double-shaft version, two Maltese wheels with double translation are used. The Maltese wheels are supported by sliding bearings on the outer surface of a bearing sleeve connecting a bearing flange and the column of three single-phase power switches arranged in a row. On the bearing flange are located a known spring energy accumulator and a gear wheel performing a half revolution of switching, which through the rod actuates the spring energy accumulator. A corresponding double translation is mounted on the shaft of this gear. The three single-phase power switches are mounted in a common bisected insulating cylinder. Attached around it for each switch are an even current carrying ring, an odd current carrying ring and a current draining ring. They are alternately connected to fixed contact elements arranged on the inner surface of the insulating cylinder of the oil pan, by current-carrying lamellae attached to insulating columns driven by the corresponding Maltese wheels. In the single-shaft version, the fixed contact elements are formed as arcs, as in (1), and in the two-shaft version, they are separate contact elements. There is also a side-mounted pre-selector formed by individual carriers for each phase and an isolation column actuated by a Maltese wheel-connected two-position Maltese sector and rod.

A disadvantage of this step regulator is that the movable contact bridges cannot be installed where contact plates are used. The location is not available. Therefore, the removable part cannot be removed and inserted into the oil pan. It has been suggested that this can be done if the isolation columns supporting the movable bridges are rotated 90°, but it is not shown how this is done. The analysis shows that this is possible, but it requires a larger oil pan diameter, complicates the design and makes it more unstable.

Another disadvantage is that the arrangement of the column of power switches in a cut insulating cylinder makes installation difficult and

3/11 makes it unstable because after cutting the cylinder halves are deformed.

A disadvantage is that the Maltese wheels are on sliding bearings, which do not ensure stable guidance of the insulation column. It can be crossed and seizing of the bearing surfaces can occur.

TECHNICAL ESSENCE OF THE INVENTION

The object of the invention is to create a step voltage regulator having mechanisms for actuating the power switches and the selector which provide maximum unification for different numbers of contact rows. Their hinged joints should be based on rolling bearings. The selector drive system is simplified and combined with the selector mechanisms. Single-phase power switches to be independent products and to be connected in a storey-arranged column by means of unified insulating elements. To provide a way for easy installation of the lamella movable contacts of the selector, ensuring unhindered installation and disassembly of the removable part in the oil pan.

The task is solved with a three-phase stepped voltage regulator with tiered single-phase power switches, containing an oil vessel composed of a bearing head, an insulating cylinder and a bottom. In the oil pan there is a removable part supported by a flange attached to the bearing head, on which are mounted a spring energy accumulator, a gear with interrupted action and a gear for their operation. A column of three tiered single-phase power switches is secured by means of a metal bearing sleeve mounted to the flange. Around the column is located the contact system of the selector, which is two-shaft.

According to the invention, the metal bushing attached to the supporting flange is an even-profile bushing with a toothed ring mounted on rolling bearings, at the lower end of which an odd-profile bushing with a toothed ring with the same number of teeth is mounted on rolling bearings. The two ring gears are meshed with an even block and an odd block respectively, each block consisting of a small gear and a worm gear. The two Maltese wheels ss rotate by means of a double translation mounted on a shaft which is connected by a freewheel clutch to the shaft of a pinion gear making a half revolution of switching. A flange is mounted on the lower face of the metal sleeve, to which the column is clamped

4/11 formed by three single-phase fully mounted in whole insulating cylinders power step switches connected to each other through identical insulating cylinders. An even arm connected to an even insulating column is mounted to the even profile bushing with a gear ring, and an odd arm connected to an odd insulating column is mounted to the odd profile bushing with a toothed ring. The two insulating columns carry correspondingly even, odd and output movable contact bridges with horizontally located contact plates, which cover fixed contact elements on both sides. An easy way of mounting and dismounting the removable part is provided when using this type of contact bridges.

The spring energy accumulator is directly connected, without an intermediate gear, to the drive shafts of the three single-phase h power switches, since the angle of rotation during switching is the same.

The two Maltese wheels have six spokes and rotate in two steps of the double translation of an angle of 120°. At the same center distance, the transmission ratio expressed by the number of teeth of the small gear to the number of teeth of the large gear for the contact rows of the selector K10, K12, K14 and K18 with 0.6, 0.5, 0.428 and 0.33, respectively.

The shaft of the double translation and the shaft carrying the even block and the odd block are supported between the bearing flange and the plate connected to it by several columns. At the lower end of the second shaft is caught a two-position Maltese sector, which interacts with a disc is a roller attached to £ the lower face of the odd profile sleeve with a ring gear. The upper end of the second shaft protrudes above the flange and has an arm connected by a rod to an arm engaged to a shaft actuating the selector when switching from K9 to K1 and back.

An easy way to mount and dismount the removable part carried by the flange is provided. It has a working position and a mounting position. In the working position, the contact bridges are connected to the stationary contact elements and the step regulator can perform its functions. In the mounting position, the removable part carried by the flange is rotated by an angle β, which is half of an angle a between two adjacent fixed contact elements of the selector. For the different contact rows K10, K12, K14 and K18, angle β is 18°, 15°, 12.5° and 10°, respectively. The removable part in the installation position can be unhindered

5/11 in and out in the oil pan. Thus, the removable part can be mounted outside the oil pan and then lowered into it in the mounting position and rotated into the operating position. If revision is necessary during operation, the removable part is rotated from the working to the installation position and pulled up.

In order for the removable part in the installation position to be inserted and removed into the oil pan without hindrance, the design of the current-carrying rings mounted on the inner surface of the insulating cylinder of the oil pan must be changed. Two options are available. Given that the assembly and disassembly of the removable part can be done only at one location of the contact bridges, for example, on K1 and K10, the current-carrying ring is divided into two half-rings with channels between them, through which the contact bridges pass. The two half-rings are electrically connected by short outer arcs. This option avoids possible errors from displacing the removable part relative to the oil pan.

The second option offers assembly and disassembly in all situations. In this case, the current-carrying rings are replaced by single fixed contact elements that are electrically connected to external connections. With this option, one should be very careful during assembly and disassembly.

The rotation from the working to the installation position and vice versa can be realized by having a tangential channel on the periphery of the bearing flange, which is fixed in two end positions by a pin mounted on the bearing head. Thus, the rotation of the bearing flange is limited to the corresponding angle β. On the periphery of the support flange are fitted two lugs, preferably with two holes, to which lever pins can be coupled. By means of one or two such levers, the rotation of the bearing flange can be done manually. Rotation can also be done by means of a tensioner consisting of two hooks with left and right threads and the corresponding nuts mounted in the housing.

On the supporting flange and on the bottom there are ribs and holes through which the correct operation of the contact systems can be observed during installation. After the assembly is completed, the bottom is closed oil-tight by a cover.

An advantage of the three-phase stepped voltage regulator with staggered phases according to the invention is that the mechanisms that drive the contact systems for the individual contact rows of the selected one are highly unified. Only the dental gums are changed, and for cutting the

6/11 gears are available on specialized machines. Another advantage is that all parts are bearing and rolling bearings. It is also an advantage that the mechanical system for driving the pre-selector is simplified, as it is combined with that of the mechanisms driving the contact systems. An advantage is also the use of fully mounted single-phase power switches, which are stable and provide quick installation at different rated voltages. A significant advantage is that an easy way of mounting and dismounting the removable part is provided, by which contacts with a high electrical load are used.

EXPLANATION OF THE ATTACHED FIGURES

An exemplary implementation of the three-phase stepped voltage regulator is a staggered phases, according to the invention, is shown in the attached figures, of which:

Figure 1 is a longitudinal section of the step voltage regulator.

Figure 2 - top view of the spring energy accumulator with the cover removed.

Figure 3 - cross-section through the intermittent selector mechanisms. A coarse step preselector variant is also shown.

Figure 4 - cross-section through the mechanisms actuating the pre-selector.

Figure 5 - longitudinal section through the mechanisms of fig. 4.

Figure 6 - cross-section through the oil pan at the selector level with ten contacts per phase and pre-selector reverser.

Figure 7 - working position of the selector when contacts K1 and K10 are switched on.

Figure 8 - mounting position of the selected.

Figure 9 - top view with cover removed showing mechanisms for turning from working to mounting position.

Figure 10 - lever for turning from working to installation position and vice versa.

Figure 11 - screw mechanism for rotation from working to installation position and vice versa.

7/11

Figure 12 - cross-section above a cut contact ring providing assembly of the removable part.

Figure 13 - ribbed bottom flange of the oil pan providing position control.

EXAMPLES OF IMPLEMENTATION OF THE INVENTION

The oil tank of the step regulator is composed of a bearing head 1 with a flange 2 and a cover 3, an insulating cylinder 4 and a ribbed bottom flange 5, through the holes of which the operation of the selector can be observed. At the end of the installation, it closes oil-tight with a bottom cover 6. A removable part carried by a metal flange 7 and a metal sleeve 8 attached to it is installed in the oil pan. A known spring energy accumulator 9 is located on the flange 7 and is charged through the rod 10 of a gear wheel. 11 performing half a switching revolution. It is rotated by a smaller gear 12 making one revolution of switching, which is connected by a shaft 13 to a known worm gear with mechanisms 14. Its input shaft 15 is coupled to a motor drive, not shown.

An even profile bushing with a gear ring 16 is mounted on the metal bushing 8 by means of rolling bearings, at the lower end of which an odd profile bushing with a toothed ring 17 is supported by means of rolling bearings. The toothed ring 16 is connected to an even block 18 consisting of a small gear wheel 19 and a Maltese wheel 20. A ring gear 17 is connected to an odd block 21 of the same construction. The even block 18 and the odd block 21 are rotated alternately by a double translation 22 mounted on a shaft 23, which is connected by a freewheel clutch 24 to a gear 11, the shaft of which is supported in a sleeve 25 fixed to the flange 7. The two blocks 18 and 21 are mounted by rolling bearings on a shaft 26. Shafts 23 and 26 are supported at their lower ends to a plate 27 connected to the flange 7 by four columns 28.

The drive of the shaft 29 of the pre-selector is made by a disc 30 with a roller 31, caught on the lower face of the profile sleeve with a gear ring 17. When passing through the middle position of the selector, the roller 31 turns the two-position sector 32 mounted on the shaft 26, which protrudes above the supporting flange 7, with an arm 33 at its end. This arm is connected by a rod 34 to an arm 35 clamped to a shaft 29. The shaft 29 is supported in a sleeve 36 fixed to the bearing head 1.

The spring-energy accumulator 9 is connected to a drive shaft 37 bearing in a metal sleeve 8. Shaft 37 switches the three floor-arranged

8/11 single-phase power switches A, B, C. The power switch is a self-contained assembly unit housed in an uncut insulating cylinder. This makes it stable while simplifying the overall installation at different rated voltages. An even contact ring 38, an odd contact ring 39, and a terminal contact ring 40 are fastened to the outside of the insulating cylinder of the single-phase power switch.

A flange 41 is mounted on the lower face of the metal sleeve 8, to which an insulating cylinder 42 connecting the flange 41 to the switch A is attached. Analogous insulating cylinders connect phases A to B and B to C. Thus a stable column is formed. The front metal rings of the insulating cylinders 42 are also shaped as screen rings. A bottom 43 with an axis 44 is attached to the lower face of the switch C, which in the working position is inserted into a hole 45 of the bottom flange 5. The transmission of the rotation from the spring energy accumulator 9 to the switches Λ, B and C is done in a known way by ribbed insulating shafts 46. With 47 is marked the entire insulating cylinder of the power switch.

An even arm 48 is attached to the even profile sleeve with a gear ring 16, and an odd arm 49 is attached to the odd profile sleeve with a gear ring 17. The upper end of an even vertical insulating column 50 is attached to the even arm 48, the lower end of which is connected to arm 51. Respectively, an odd insulating column 53 is mounted between arm 49 and arm 52. Even contact bridges 54 formed by contact plates are attached to the even insulating column 50. They alternately connect the even contact rings 38 with fixed even contact elements 55 mounted on the insulating cylinder 4. On the column 50, under contact bridges 54, output even contact bridges 56 are also caught, which connect rings 40 with an external current collector ring 57 mounted on the inner surface of the insulating cylinder 4. In a similar way, odd contact bridges 58 are attached to the insulating column 53, which connect rings 39 with odd fixed contact elements 59. On the column 53, under bridges 58, odd output contact bridges 60 connected to a ring 57 are attached.

Selectors with different numbers of fixed contacts per phase are known to be used, namely K10, K12, K14 and K18. At the same distance between centers, the ratio of the teeth of gear wheel 19 to the teeth of ring 16, respectively 17, is 0.6, 0.5, 0.428 and 0.33, respectively. Only the tooth rims, for which there are specialized machines for cutting, are changed, and all other details are preserved.

9/11

A known preselector is used, comprising upper and lower bearing sectors 61 and 62, a segment 63 cut from an insulating cylinder, fixed contact elements 64 and 65 and contact bridges 66 carried by an insulating column 67 attached to an upper arm 68 and a lower arm 69 bearing on an axis 70 .

In fig. 6 shows a cross-section of the 10-contact stepper regulator and preselector-inverter. Next to the fixed contact elements, their number from K1 to K10 is also given. K9™ and K10™ contacts are included. With pos. 71 the output from contact K10 is indicated. In fig. 3 shows a coarse step preselector with the same mechanical drive system. It can also be used as a pick-turner, but the construction of fig. 6 is simpler.

The operation of the step regulator is as follows. The motor drive, not shown, rotates the input shaft 15 and the worm gear 14. It reduces the movement to one revolution per shift of the shaft 13 of the gear wheel 12, which rotates the gear wheel 11 for half a revolution per shift. Through the rod 10, the spring-energy accumulator 9 is charged and at the same time the double translation 22 rotates one of the blocks 18 or 21 and the corresponding profile sleeve with a gear ring 16 or 17 switches the movable contact bridges 54 or 58 and they are moved to the adjacent selected position. While, for example, the even contact bridges 54 are switched, the current flows through the odd contact bridges 58. At the next switching, the roles are reversed. After the selection is completed at the end of switching, the spring energy accumulator 9 is released and the three single-phase power switches A, B and C are step-switched. When switching from contact K9 to contact K1, the pre-selector is switched.

The step regulator according to the invention must be able to provide installation of the removable part in the oil pan. This will allow revisions to be made during operation. Here is a simple way how this can be done. It is illustrated by figures 7 to 13. The removable part carried by the metal flange 7 has two working positions, in which the contact systems are included (fig. 7), and installation, in which the flange 7 is rotated through an angle |i (fig. 8 ). In this position, the even contact system 54 and the odd contact system 58 are located between the fixed contacts 55 and 59, and the removable part can be inserted and removed without hindrance. Angle β is half of angle a. Its values for rows K10, K12, K14 and K18 are 18°, 15°, 12.5° and 10°, respectively. In fig. 7 and fig. 8, the movable contacts 54 and 58 are located on the fixed contacts K10 and K1. In this position, the terminal contact ring 57 is divided into two parts 72 with terminals 73 and channels 74

10/11 between them (Fig. 12). The connection between the two half-rings 72 is made by means of external current-carrying arcs 75. In this variant, the assembly of the removable part takes place only in the arrangements of figures 7 and 8. Thus, no mistake can be made when connecting to the drive mechanical system. Another option is when the insertion and removal of the removable part can be done at any arrangement of the contact system. In this case, the ring 57 is replaced by fixed contacts similar to the contacts 57 and 59, and they are connected externally to the insulating cylinder 4.

How the rotation of the metal flange 7 can be done is illustrated by figures 9, 10 and 11. In the working position, the removable part is centered above with the bearing flange 7 entering the round hole of the bearing head 1, and below through the axis 44 entering the hole 45 of the bottom 5. A fixing pin 76 is mounted on the bearing head 1, and on the periphery of the flange 7 there is a channel 77, matched in length with an angle β. Two plates 78 with larger and smaller holes are mounted on the flange 7 (Fig. 10). After removing the bolts that fix the flange 7 to the bearing head 1 and removing the rod 34, the bearing flange can be rotated counterclockwise by the required angle β. This can be done by one or two levers with the configuration shown in fig. 10. Another option is through the tensioner shown in fig. 11. It has two hooks with right and left thread and body with nuts and hex. It is connected with a bolt 79 on the flange 2 and the small hole on the plate 78. Located along axis I provides rotation from working to installation position, and along axis II the opposite. On the flange 7 and on the bottom 5 there are ribs 80 and openings 81, through which the correct installation can be controlled and the operation of the contact systems can be monitored.

Claims (9)

1. 'Three-phase stepped voltage regulator with staggered phases, containing an oil tank consisting of a supporting head, an insulating cylinder and a bottom, in the oil tank there is a removable part carried by a flange attached to the supporting head, on which a spring energy accumulator, a gear are mounted with intermittent action and a gear for their actuation, and by means of a metal bearing sleeve mounted to the flange is fixed a column of three tiered single-phase power switches, and around the column is located the contact system of the selector, which is a two-shaft, characterized in that on the metal sleeve (8) attached to the supporting flange (7) is mounted on rolling bearings with an even profile bushing with a toothed ring (16), at the lower end of which an odd profiled bushing with a toothed ring (17) of the same number is mounted on rolling bearings teeth, the two ring gears are meshed with an even block (18) and an odd block (21) respectively, each block being composed of a small gear (19) and a malt wheel (20), the two malt wheels are rotated alternately by a double translation ( 22) mounted on a shaft (23), which is connected by a freewheel coupling (24) to the gear shaft (11), on the lower face of the metal sleeve (8) a flange (41) is mounted, to which a column is clamped formed by three single-phase fully mounted power switches (A, B, C) connected to intermediate insulating cylinders (42), to the even profile sleeve (16) an even arm (48) connected to an even insulating column (50) is mounted, and to the odd profile sleeve (17) an odd arm (49) is mounted connected to an odd insulating column (53), the two insulating columns (50, 53) carry even (54), odd (58) and output (60) movable contact bridges with horizontal contact plates, providing an easy way to mount and dismount a removable part with this type of contact bridges. 2. Three-phase step voltage regulator according to claim 1, characterized in that the spring energy accumulator (9) is directly connected, without an intermediate gear, to the shaft (37) which switches the power switches (A, B, C) . 3. A three-phase step voltage regulator according to claims 1 and 2, characterized in that the two Maltese wheels (20) have six channels and are rotated in two steps by the double translation (22) of an angle of 120° per switching , in which the transmission ratio from the number of teeth on the gear wheel (19) to the number of teeth on the ring gear (16, 17), 1/3 with the same center distance, for contact rows K10, K12, .K14 and K18 is 0.6, 0.5, 0.428 and 0.33, respectively. 4. A three-phase step voltage regulator according to claims 1, 2 and 3, characterized in that the shaft (23) of the double translation (22) and the shaft (26) on which the even block (18) and the odd block are established (21) are supported between the supporting flange (7) and a plate (27) connected to the flange (7) by means of several columns (28), and on the lower end of the shaft (26) a two-position Maltese sector (32) is caught, which interacts with a disk (30) with a roller (31) and rotates a shaft (26) when switching from K9 to K1, and the upper end of the shaft (26) protrudes above the flange (7) and has an arm (33) connected by a rod (34) with arm (35) clamped to the selector shaft (29) and thus the selector is switched. 5. Three-phase step voltage regulator according to claims 1, 2, 3 and 4, characterized in that the removable part carried by the flange (7) has an operating position in which the contact bridges (54, 56, 58) are connected to the corresponding stationary contact elements (55,57,59) and the mounting position in which the removable part carried by the flange (7) is rotated at an angle β having values of 18°, 15°, 12.5° and 10° for the corresponding contact rows K10, K12 , K14 and K18, in which case the movable contact bridges can freely move up and down. 6. Three-phase step voltage regulator according to claims 1, 2, 3, 4 and 5, characterized in that in a fixed position of assembly and disassembly (contacts K1 and K10) the current-discharge ring (57) is composed of two half-rings ( 72) with channels (74) between them offset at an angle β and connected electrically by external arcs (75). 7. Three-phase step voltage regulator, according to claims 1, 2, 3, 4 and 5, characterized in that if it is necessary to be able to mount and dismount the removable part in any position, the current carrying rings (57) are replaced with contacts analogous to (55 and 59), which are electrically connected to the outside of the insulating cylinder (4). 8. Three-phase step voltage regulator according to claims 1 to 7, characterized in that the switching from the operating position to the installation position and vice versa can be carried out by having a tangential channel (77) fixed at both ends of the supporting flange (7) position of a limit pin (76) mounted on the bearing head (1) allowing a tangential rotation of an angle β, to the periphery of 2/3 of the flange (7) are fitted with two lugs with two holes each allowing special levers to be attached to them, through which the rotation can be realized, as this can also be done by means of a tensioner composed of two hooks and nuts with a right and left thread. 9. Three-phase step voltage regulator according to claims 1 to 8, characterized in that the supporting flange (7) and the bottom (5) have ribs (80) and openings (81) through which, during installation, it is possible to observe the correct operation of the contact systems is selected, and after the installation is completed, the bottom is closed oil-tight by a disc (6).