High-voltage vacuum switch

FIELD: high-voltage vacuum switches for electromagnet control gear.

SUBSTANCE: proposed high-voltage vacuum switch incorporating electromagnetic control system with polarizing permanent magnet for holding movable contact in two extreme positions upon deenergizing electromagnet control windings has corrugation on each of lateral parts of additional flexible contact in center or closer to contacting point, top of this corrugation being brought to pin contact up to stop. When released, distance between tops of corrugations on lateral parts of additional contact is at least shorter than diameter of pin contact and corrugation bending line is disposed at same level and perpendicular to longitudinal axis of movable pin contact. Proposed switch may be found useful for heavy-power stationary mobile and airborne electrical and radio equipment where low power requirement and easy control of components are essential.

EFFECT: enhanced cyclic strength of membrane, reduced high-frequency power loss, enhanced inherent mechanical-resonance frequency.

1 cl, 2 dwg

The invention relates to high-voltage vacuum switches that use electromagnetic control system with polarizing permanent magnet retention of the rolling contact of two extreme positions after removing the supply voltage from the control windings of the electromagnet.

The proposed switch is designed for switching high-voltage electrical and electronic circuits and can be used in powerful stationary, mobile and on-Board electrical and electronic equipment, one of the most important requirements which is a small consumption of electric energy elements in their management.

The switch in the instrument can be used for switching power sources and loads, antenna circuits, outlets coil high-frequency circuit, high-voltage capacitors high-frequency circuits in the antenna tuning devices, etc.

Known vacuum switches, switches and relays with polarizing permanent magnet used for this purpose have a number of disadvantages.

For example, in the vacuum switch described in [1], polarizing permanent magnets fixed directly on the high-voltage pins, and the control winding is located on the shell of glass, i.e. polarize the third magnetic flux in the switch is closed through long air gaps. The presence of large air gaps leads to a large magnetic resistance and a large flow of energy dissipation of the magnetic field. Large energy loss of the magnetic field substantially reduce the force holding movable contact in its two extreme positions, which dramatically reduces the resistance of the switch to mechanical loadings. In addition, the reduction in contact pressing leads to increased contact resistance and, consequently, to higher losses and increased heating of the switch.

Another significant disadvantage of this switch is its low bandwidth current at a high frequency, because of the small cross-section and great length of the movable contact. In addition, the location of the permanent magnets on the findings, the conclusions of Kovar, and the armature of the electromagnetic control system of magnetic metal (permendur) exclude the possibility of transmission through the switch even small currents of high frequency.

In the construction of the vacuum relay switch [2] adopted measures to reduce the flow of the dispersion of the magnetic field of the permanent magnet and the provision of transmission through the closed contacts of the high frequency current.

However, this vacuum relay switch has a significant drawback consisting in the fact that the sun is bedstvie small working section movable contact at a high frequency and especially its flexible membrane, due to the "skin effect", in comparison with the cross section of the conclusions of the relay has a low bandwidth current at a high frequency. Due to the small working section of the membrane, especially at its junction with a movable contact, there is a great resistance of the high-frequency current, which eventually leads to a significant loss of high frequency energy for heating the membrane at its junction with a movable contact (up to temperatures of the order of 250-350°). In conjunction with the mechanical load on her from atmospheric pressure and cyclic bending at the time of switching the movable contact this leads to a sharp decrease in cyclic durability of the membrane, and consequently a reduction in the reliability of operation of this relay.

The closest technical solution is to design the vacuum switch proposed in [3]. The elimination of the above-noted drawbacks in its design achieved by the fact that fastened it on a flexible diaphragm movable contact rod type provided with an additional elastic tape contact P - or Λ-shaped, the sides of which are located on both sides of the rolling contact is formed between the movable and each of the stationary contacts gap and secured the lower ends directly at the output of the rolling contact. In addition, additional tape contact done what h can move its upper part along the movable contact when the deflection of the side parts, after the circuit, to generate the contact pressure. Moreover, the sides of the auxiliary contact mounted relative to the movable contact with the gap, the magnitude of which is determined by the required contact by pressing and is equal to or greater than the deflection of the lateral parts of the additional contact. Thanks observed provided a substantial increase in noise through the closed contacts of the high frequency voltage and cyclic strength of the membrane.

However, this vacuum switch [3] has significant drawbacks, which include the following. Providing movement of the upper part of the additional tape contact along the rod movable contact in said switch causes the need for a guaranteed gap between its side surface and lateral parts more belt contact, and between the side surfaces and the surface of the hole in the top for more belt contact. In conjunction with the manufacturing tolerances this gap (backlash) is the cause of the increase of the deflection of the membrane and thus reduce its cyclic strength. In addition, the presence of this gap reduces contact pressure, because of the displacement of the rolling contact with the bending of the membrane, which was to be sent n the contact pressure, in fact, is to overcome the parasitic gap. The decrease in the contact pressing causes an increase in resistance when the contacts are closed, and therefore, power loss, high-frequency heating of contacts and increasing the likelihood of breaking the circuit when the contacts are closed when exposed to vibration and shock loads. The consequence is a reduction in the reliability and durability of the switches. It should also be noted that because of the long side part of the additional elastic tape contact have a relatively low natural frequency of mechanical resonance. This significantly limits the operating frequency range of vibration loads this type of radio buttons.

The aim of the present invention is to increase the cyclic strength of the membrane, reduction of power losses high frequency and increase the natural frequencies of mechanical resonance.

This goal is achieved by the fact that unlike known in the proposed vacuum switch each of the lateral parts of the additional elastic contact in the middle or closer to the point of contact provided with a Flexi hose, the top of which is directed to the rod contact to another to him, and in a free state, the distance between the peaks of the corrugation of the side parts of the auxiliary contact of the selected RA is th at least smaller than the diameter of rod rolling contact on the value of 1-2 tolerance of its manufacture, and the bend line of the corrugation is on one level and is made perpendicular to the longitudinal axis of the movable rod contact.

The supply of each of the lateral parts of the additional elastic contact Flexi hose, the top of which is directed to the rod contact until it stops on it, and run the distance between the peaks of the corrugation in the free state at least smaller than the diameter of rod rolling contact on the value of 1-2 tolerance of its manufacturing ensures the installation of the movable rod contact between the tops of the corrugation additional tape contact with the guaranteed tightness. This setup eliminates the possibility of the presence of parasitic gap between adjacent contact when switching surfaces rod movable contact and the tops of the corrugation of the additional contact. In turn, the exception of "parasitic" backlash reduces required to switch the stroke of movable contact by an amount which previously required to move the movable contact to "liquidate" parasitic gap (dead stroke) between the side surface of the movable contact and the surface of the holes in the additional contact. Reducing the stroke of the rolling contact reduces the deflection of the membrane and increases its cyclic strength.

In addition, the exclusion of "parasitic" Luv is and by planting sliding contact with the "tension" between the corrugations additional tape contact increases contact pressure, as part of moving the movable contact, which earlier in the presence of the backlash was going to overcome it, in the proposed vacuum switch is to increase the contact pressure. This leads to a decrease of the transition of the contact resistance, which in turn leads to lower power losses, high frequency by passing high frequency current through the closed contacts of the switch.

Execution of bumps on the sides of the additional tape contact in the middle or closer to the point of contact, with the support of the corrugation on the rod movable contact, reduces twice neopentyl part of the lateral parts of the additional elastic tape contact without changing their total length. As a result, this more than doubles the natural frequency of mechanical resonance, as evidenced by the following. The natural frequency of the mechanical resonance of the elastic flat plate of length 1 is defined by the equation:

When reducing the length of the plate 2 times the natural frequency of a mechanical resonance will vary and will equal:

Moreover, the increase in natural frequency of a mechanical resonance of the additional elastic tape in contact 2.82 times achieved without changing its overall length.

The location of the line SG is BA bumps at the same level relative to each other and perpendicular to the longitudinal axis of the rod sliding contact provides the same experience each part of the additional elastic contact and the same their resistance to vibration and shock loads.

However, due to occur between the peaks of the corrugation and the rod surface contact friction, with the closure of the circuit significantly reduces "bounce" contacts, which reduces the reaction time for the formation of a reliable contact.

1 shows a General view of the design of our vacuum switch figure 2 - cross section along a-a in figure 1.

Vacuum switch consists of a vacuum switching part and the electromagnetic control system of polarized type with retractable core.

Vacuum switching part consists of three identical coaxially arranged cylinders 1, 2 and 3. Between the ceramic cylinders are thin-walled copper findings 4 and 5 fixed and the output 6 of the rolling contacts, vacuumpack soldered to the end surfaces of the ceramic cylinder. Conclusions 4 and 5 are made in one piece with the fixed contacts 7 and 8 to reduce the resistance of ecoprojection and thus reduce heat. In the gap between the fixed contacts 7 and 8 is the movable contact 9 is in the form of a round rod of molybdenum or other non-magnetic highly conductive, mechanically strong and heat-resistant material. The movable contact 9 and the upper end enters the opening in the upper part to anitelea elastic tape contact 10 of the U-shape of molybdenum or other non-magnetic highly conductive elastic and heat-resistant metal. The lower end of the movable contact 9 vacuumpack span with mebrana 11 of molybdenum or non-magnetic highly conductive alloy having a high cyclic durability bending, vacuum density and thermal resistance. It protruding from the membrane 11 part movable contact 9 is mechanically firmly attached, for example, by soldering the insulating rod 12 made of ceramics, which serves to isolate the movable contact 9 from the electromagnetic control system. At the end of the ceramic rod (insulator) 12 mechanically secured additional sleeve 13, which serves to eliminate abrasive wear of the leash on the ceramic insulator 12. The sleeve 13 may be made of dielectric, for example, made of hard plastic filled with glass, or metal, for example, of brass or other metal or alloy with a low coefficient of sliding friction in tandem with the material of the lead 21. The sleeve 13 may be made and combined, i.e. of the dielectric and metal, while the metal tube is pressed in a reduced state on the external surface of the additional sleeve 13. Additional movable tape pin 10 of the lower ends of the side pieces rigidly mechanical and electrical firmly attached (by soldering, riveting, welding, and others) directly to the output 6 of the movable contact 9. On each of the side parts on the auxiliary contact 10 in the middle or closer to the point contact is made with corrugations vertices in the direction to the rolling pin 9 to focus on him with tension. At the same time to ensure the landing movable contact 9 between the peaks of the corrugation auxiliary contact 10 with the tightness of the distance between the peaks of the corrugation is selected smaller than the diameter of the rolling contact 9 for at least 1-2 of admission on its diameter. The shape of the corrugation is not so essential for, and their location relative to each other and movable contact can have a significant impact on the operation of the switch. So, for example, at the location of the peaks of the corrugation at different levels relative to each other, the effort to switch movable contact will be different on each of the stationary contacts. This will take place at the location of the bend line of the tops of the corrugation is not perpendicular to the axis of the movable contact 9. In principle, landing rolling contact with tightness in the middle of the lateral parts of the auxiliary contact 10 may be provided by the program in this location on the movable contact 9 of the projections in the direction to the side auxiliary contact 10 without bumps on his side. However, this option is technologically exercise more difficult. To the lower end of the ceramic cylinder 3 is mechanically firmly by soldering attached to the adapter ring 14, which serves for fastening the vacuum switching part with electromagnetic control system of rolling contact. To the free end of pin 4 is soldered aquaplate W is JBA 15 of non-magnetic metal, soldering which to reduce thermomechanical stresses in the zone of junction is made with the use of the wear ring 16 made of molybdenum or Kovar with a highly conductive coating. To maintain the volume switch operating pressure (vacuum better than 10^-5mm Hg) within a specified period of service is nerability getpagetitle 17 fixed via Nickel plate 18 on the output movable contact 6. The above variant of the construction of the vacuum switching of the switch provides messagelog degassing and sealing. In the case of changelogo method of pumping in the center of the washer 15 soldered vacuumpack tube Stengel 37, which after vacuum of ATPA from udachnogo post is protected by a cap 38.

Electromagnetic control system is enclosed in a housing 19 and includes the body of the electromagnet 20 of magnetic metal in the upper part of the base of the ledge that serves as a support place of a lead 21 of the elastic metal. The lead 21 is fixed on the housing of the electromagnet by means of spring plates 22 are rigidly by welding is attached to the housing of the electromagnet 20. The lead 21 is movably connected to the plate 23 fastened rigidly to the rod 24 of non-magnetic metal, which is in turn rigidly fixed to the core 25 from m nicomaco metal. The bottom stroke of the core 25 is limited by the base 26 of magnetic metal. To ensure movement of the core 25 in the axial direction it is placed in the guide sleeve 27 of a nonmagnetic metal such as brass. On the outer surface of the sleeve 27, strictly in the middle and diametrically opposed, fixed two permanent magnet 28 and 29, made in the form of sectors and having a radial direction of magnetic field lines (with radial magnetization). On both sides of the permanent magnets 28 and 29 are control winding 30 and 31 are wound on the bobbins 32 and 33. The system of the windings and the permanent magnets are closed with a protective cylinder 34 of insulating material. The soldering of the wires of the windings is made to the conclusions 35 of the insulator 36.

At the junction of the vacuum switching part with electromagnetic control system additional sleeve 13 is included in the circular hole of the lead 21 with a guaranteed gap, providing the mobility of the joints with minimum parasitic gap. Then the adapter ring 13 and the housing 19 is rigidly fastened to each other, for example, by welding.

The vacuum switch has a remote impulse control, i.e. it consumes electrical energy only in the moment of switching. In the initial state, the movable contact 9 and the auxiliary contact 10 lock is by Uta on one (any) of the stationary contacts for example, on the upper stationary contact 8. In this case, the high-frequency current passes from terminal 5 on the stationary contact 8 and further auxiliary contact 10 and the fixed contact 9. Thus most of the current goes through the side of the additional pin 10 to pin 6, and a smaller part on pin 6 goes through the movable contact 9 and the membrane 11.

In the initial position for the considered case, the magnetic flux of permanent magnets is closed on the following path: permanent magnets 28 and 29, the core part of 25 adjacent to the base 26, the base 26, the cylindrical part of the housing of the electromagnet 20 and further permanent magnets 28 and 29.

To switch movable contact 9 and the auxiliary contact 10 on the lower stationary contact 7, the lower control winding 31 is fed pulse voltage with a polarity that generates the control winding of the magnetic flux control, the opposite polarizing magnetic flux of the permanent magnet in this branch of the magnetic circuit. When reaching in the magnetic circuit of the current branch equality polarizing and control of magnetic flux due to the magnetic flux of the second branch and the instantaneous redistribution of the primary magnetic flux in the second branch, the core 25 is transmitted to the second stable state to the base of the electromagnet 20. P and the forward axial movement of the core 25 by moving the links of the lead 21 is converted into rotational motion of the lead 21 and the associated movable contact 9, which is thrown to the fixed contact 7. Kinematic scheme is chosen in such a way that the closure of the contacts occurred somewhat earlier than the core 25 will reach the base of the housing of the electromagnet 20. Upon further movement of the core 25 on the way to the base of the electromagnet 20, due to the lateral deflection of the additional elastic contact 10 and the lead 21 and the elastic properties of their material, creates the required contact pressure. To return the movable contact 9 to the upper stationary contact 8, the voltage corresponding to the polarity and magnitude is supplied to the coil 30. The switching processes and the creation of the contact is pressed on the fixed contact 8 similar to that described above when the switch movable contact 9 on the stationary contact 7.

To increase the electric strength between the high voltage pins on the outer surface of the entire surface of the ceramic shell can be covered with a layer of high-frequency dielectric 39, for example, sealers or silicone varnish.

In comparison with known offer vacuum switch has a number of advantages, which are:

- excluding the impact of parasitic gap between the core pin and the hole in the upper part of the movable contact;

- increase cyclic of what sostoiali membrane and stabilize the contact pressure level;

- reduction of energy losses high frequency and hot contacts;

- improve the reliability and durability;

- increase the natural frequency of mechanical resonance of the moving system switch;

- reduction of contact bounce at the moment of closing of the contacts.

Sources of information

1. U.S. patent No. 3324430, CL 335-83, 1967.

2. Patent England No. 2996621, CL N 01 N 33/66, 1972.

3. Auth. mon. The USSR №938327, CL N 01 N 33/66, 1982.

High-voltage vacuum switch containing fortified in a vacuum chamber on the conclusions of the two fixed contact located between them more elastic tape contact the U-shaped rod and movable contact attached to the membrane and is connected through the insulator and the lead core, controlled by an electromagnetic control system with a polarizing permanent magnet, characterized in that, in order to increase cyclopropene membrane, reduction of power losses high frequency and increasing their frequency of mechanical resonance of the switch, each of the lateral parts of the additional elastic contact strictly in the middle or closer to the point of contact provided with a Flexi hose, the top of which is directed to the rod to contact it stops him with tension, for which the distance between the peaks of the corrugation of the side parts selected less the diameter rod movable contact, and the fold line bumps are located on one level and is made perpendicular to the longitudinal axis of the rod rolling contact.