BG66949B1 - A power switch of a step voltage regulator - Google Patents

Abstract

The power switch has a round shield (1) with a hinged to the centre drive shaft (3). On top of the shield (1) is designed an isolation cylinder with mounted on its internal surface primary and secondary immovable contacts (7). The shaft (3) has a channel (12), in which slides a U-shaped bracket (17). It is lead on two radially located axes (13), coaxially to which are placed contact springs (15), working under pressure. On the vertical axis (16), attached on P-shaped bracket (17) are hinged brackets (18), carrying movable primary and secondary contact elements (20). Above them is placed a contact ring (31), mounted to the shield (1) by vertical columns (35). Contact plates (32) connect the ring (31) to tails (36) on the main immovable contact elements (7). There is also a variant of the power switch with isolated phases for coils, connected in a triangle. The construction is identical to the described variant for connecting in a star center.

Description

Field of technology

The invention relates to a power switch for a step voltage regulator under load of power transformers. These power switches are three-phase and have designs for adjustment in a star center or for adjusting the windings connected in a triangle.

BACKGROUND OF THE INVENTION

A three-phase power switch of a step voltage regulator / 1 / is known, containing a contact system, a spring-energy accumulator and resistors. The contact system consists of a bearing round shield, an insulating cylinder and a drive star mounted in the middle of the shield. Fixed main and auxiliary contact elements are mounted on the inner surface of the insulating cylinder. Support brackets with axles are attached to the drive star, on which contact brackets with movable contact elements are located. These contact elements are guided in a radial direction by rollers in channels of the round shield. In order to reduce the vibrations of the movable contact elements, there are U-shaped contact tips with support springs. When the material of the nozzles is metal-ceramic, parallel copper contact plates are also used to conduct the current permanently.

The disadvantage of this power switch is that the drive star has a complex construction, and the mounting of the support bracket to it is one-sided. This leads to a difference in the switching process in both directions. Another disadvantage is that the U-shaped contact tips complicate the construction without protecting the permanently conducting copper contact plates from the effects of electric arcs. This can lead to overheating of their contact surfaces and a possible accident.

A three-phase power switch of a step regulator / 2 / is also known, which has a similar construction as the first one, but with three phases spaced in a radial direction, isolated from each other. The disadvantages are the same, but there is another significant disadvantage. The transverse diameter is larger, so this power switch cannot fit in an oil pan of the same diameter.

Technical essence of the invention

The object of the invention is to provide a step voltage regulator comprising a contact system consisting of a round shield, an insulating cylinder and a drive shaft. Fixed main and auxiliary contact elements are mounted on the inner surface of the insulating cylinder. Contact clamps are attached to the drive shaft, bearing movable contact elements with U-shaped metal-ceramic contact tips and parallel copper tips. The contact pressure is exerted by contact springs.

According to the invention, the drive central shaft has a radial channel and two radial guide axes for each phase. On them is mounted a U-shaped bracket with an axis, on which are mounted brackets bearing the movable main and auxiliary contact elements. Above these contact elements there is a current-carrying ring connected to the tails of the main fixed contact elements by contact plates with contact springs. These plates are driven by a star caught on the drive shaft. The conductive ring is mounted on vertical conductive columns mounted on the support shield. Coaxially on the radial axes are located contact springs, working on pressure. They push the U-brackets in a radial direction relative to the drive shaft.

Alternatively, the fixed auxiliary contact elements are mounted on supports attached to the insulating cylinder. The brackets have contact springs and a cylindrical channel in which a bolt connected to the contact moves.

In the case of a power switch with isolated phases, the contact system is the same, but the fixed contact elements are mounted on insulating pipe sectors. The drive shaft is mounted on a bearing metal sector and is connected by an insulator with a satellite gear engaged with a central gear. This gear is driven by a lever and a pulley of a spring-energy accumulator.

Descriptions of issued patents for inventions № 09.2 / 30.09.2019

An advantage of the power switch of a step voltage regulator is that the guidance of the movable contact system is symmetrical and there is no difference in the switching in both directions. Another advantage is that with metal-ceramic contact elements there is a parallel permanently conducting contact system and no electrical wear of copper contact surfaces occurs, which can lead to possible overheating and accidents. Another advantage is that vibrations can be reduced with a simpler design. Also with power switches for star and triangle the transverse gauge is the same.

Explanation of the attached figures

An exemplary embodiment of the power switch of a step voltage regulator according to the invention is shown in the attached figures, of which:

Figure 1 is a longitudinal section through the contact system of a star center power switch;

Figure 2 is a top view with partial cross-sections of the contact system;

Figure 3 is a partial section of a fixed auxiliary contact element with a support spring; Figure 4 is a longitudinal section through the contact system of a power switch with isolated phases for adjusting the windings connected in a triangle;

FIG. 5 is a top view with partial cross-sections of the contact system of FIG. 4.

Examples of the invention

The supporting structure of the contact system consists of a round supporting shield 1 and an insulating cylinder 2 connected to it (Fig. 1, Fig. 2). In the center of the support shield 1 is a bearing drive shaft 3 with a buffer system 4. The shaft 3 is rotated in a known manner by an undisclosed spring-energy accumulator by means of a drive lever 5 with a roller 6.

On the inner surface of the insulating cylinder are mounted for each phase one main odd fixed contact element 7, one main even fixed contact element 8 and between them one auxiliary odd fixed contact element 9 and one auxiliary even fixed contact element 10. The main odd 7 and even 8 fixed contact elements have connecting elements 11, through which they are connected in a known manner to unshoven cantilever contacts of an oil vessel. The drive shaft 3 has three grooves 12 at 120 ° and two per phase radial guide axes 13. They are guided by a U-shaped bracket 14 with contact springs 15 operating under pressure. A vertical axis 16 is mounted on the bracket 14, on which brackets 18 are mounted with bearings 17. At the outer end of the brackets 18 by axles 19 are attached a main odd movable contact element 20, a main even movable contact element 21, an auxiliary odd movable contact element 22 and an auxiliary even movable contact element 23. The movable contact elements 20, 21, 22 and 23 are guided by rollers 24 in radial grooves 25 of the support shield 1. The star center is realized by the terminal 26 connected to the contact element 27 attached to the shield 1. The current to the element 27 of the movable contact elements is done through main flexible connections 28 and auxiliary flexible connections 29.

Contact plates 30 of the movable contact elements can be made of copper for currents up to 300A and cermets - for larger currents. In the second case, a parallel contact system is provided, consisting of a fixed current ring 31 and movable contact plates 32 carried by a drive star 33 mounted on the drive shaft 3. The contact plates 32 have contact springs 34. The current ring 31 is connected by current columns 35. with the shield 1. The contact plates 32 are in contact with tails 36 connected to the fixed main contact elements 7 and 8. Pins 37 are mounted on them, to which an insulating disk 38 is mounted for mounting known resistors 39.

To reduce the vibrations that lead to greater electrical wear, the variant of fig. 3. The fixed auxiliary contact element 10 is supported by a spring 40 entering a channel of the carrier 41 mounted on the insulating cylinder 2. The guiding of the contact element 10 in the carrier 41 is carried out by a bolt 42 and the movement is regulated by the nut 43. . 3, the contact element 10 is pressed by a force P of the springs 15.

Figures 4 and 5 show a variant of a power switch with isolated phases. The elements

Descriptions of issued patents for inventions № 09.2 / 30.09.2019 with the same function are marked with the same numbers, although there are design differences. New are the discharge sector 44 with two columns 45 attached to the support sector 46. The fixed contact elements 7, 8, 9 and 10 are mounted on tubular sectors 47 attached to a common support plate 48. The three phases are driven by a central gear 49 , engaged with three satellite gears 50 connected to the shafts 3 by insulators 51. An insulating column 52 reinforces the sector 46 and a star 53 supports the gear 49. The current from the element 27 is through a cantilever contact 54. There is an insulating distance 55 between the three phases.

The operation of the power switch is as follows.

The spring-energy accumulator rotates the shaft 33 by a jump through the roller 6 and the switching lever 5 (Fig. 1, Fig. 2). The axes 13 move the brackets 14 counterclockwise and the drive brackets 18 move the radially movable contact elements. First, the star 33 turns off the contact system 32. Then, the contact pair 9-22 is turned on and opens the contact pair 7-20. Then close 10-23 and open 9-22 and finally close 9-22 and open 10-23. Last, contact 32 is closed. This is how the well-known "flag" switching scheme is realized. The reverse switching is done in reverse order by turning the shaft 3 clockwise. In a similar way, the switching of the power switch from fig. 4 and FIG. 5.

Claims (4)

Patent claims A power switch of a step voltage regulator, comprising a contact system consisting of a round support shield, an insulating cylinder and a driving central shaft, with fixed main and auxiliary contact elements mounted on the inner surface of the insulating cylinder and a drive shaft mounted on the drive shaft. brackets carrying movable contact elements which are pressed against the fixed contact elements by contact springs, characterized in that the drive shaft (3) has a radial channel (12) and two radial guide axes (13) for each phase, such as they are mounted U-shaped bracket (14) with an axis (16), on which are mounted brackets (18) bearing movable main and auxiliary contact elements (20, 21, 22, 23), and above these contact elements there is a current-carrying ring (31) connected to the tails (36) of the main fixed contact elements (20 and 21) by contact plates (32) with contact springs (34) driven by a star (33) connected to the shaft (3), such as the current-carrying pr a wall (31) is mounted on vertical current-carrying columns (35) mounted on the support shield (1). Power switch according to Claim 1, characterized in that contact springs (15) are arranged coaxially on the radial axes (13), acting on pressure and pushing radially the U-shaped brackets (14) relative to the drive shaft (3). Power switch according to claims 1 and 2, characterized in that the fixed auxiliary contact elements (10) are mounted on brackets (41) attached to the insulating cylinder (2), and the brackets (41) have contact springs (40) and a cylindrical channel in which a bolt (42) connected to the contact (10) moves. Power switch according to claims 1 and 2, characterized in that the fixed contact elements (7, 8, 9, 10) are mounted on insulating pipe sectors (47) and the drive shaft (3) is mounted on a bearing metal sector (46) and is connected by an insulator (51) to a satellite gear (50) engaged with a central gear (49) driven by a lever (5) and a roller (6) of a spring energy accumulator.