RU2468460C1 - Vacuum circuit breaker - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: vacuum circuit breaker contains housing divided by high-voltage insulator forming arc-extinguishing chamber with axial movable and fixed electrodes. Movable electrode is attached to housing by current lead and metal corrugation separating chamber vacuum environment from ambient environment, fixed electrode is attached by its current lead to housing of arc-extinguishing chamber via separating insulator. Electrodes are provided with annular contacts. Electrodes are designed as disks made from nonmagnetic material with slots in the form of Archimedean spiral, at that angles of spiral radius rotation have reverse direction, fixed electrode has spiral radius rotation φ>0 and movable electrode has spiral radius rotation φ<0.3.

EFFECT: increasing concentration of magnetic field in intercontact interval, reducing electroerosive wear of contacts and improving commutating characteristics.

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Description

The invention relates to electrical engineering, namely to power switching equipment, and is intended for use in vacuum circuit breakers and contactors of direct and alternating current.

A vacuum current switch is known, comprising an arcing chamber with axial movable and fixed electrodes with end contacts fixed to the camera body, and a magnetic system forming a field transverse to the axis between the contacts. The magnetic system is located along the axis from the side of one of the contacts and is made forming a transverse radial field [RF Patent No. 2230385, IPC Н01Н 33/664 (2006.01), publ. 2004.06.10].

The disadvantage of this vacuum circuit breaker is the design of the central part of the camera housing located inside the fixed electrode with an annular contact. This part of the housing is electrically connected to a fixed contact, and the magnetic field near it is perpendicular to it, since it is axial in nature. The arc arising between the contacts when they open is pushed out of the working gap and can stably burn between the central part of the movable electrode and the central part of the housing located inside the stationary contact, since the electric and magnetic fields are parallel to the axis. Thus, the switching characteristics of the circuit breaker deteriorate: the value of the switching current decreases and the time of interruption of the arc increases.

The closest adopted for the prototype is a vacuum current switch [RF Patent No. 2400855, IPC Н01Н 33/664 (2006.01), publ. 2010.09.27], containing an arcing chamber with axial movable and fixed electrodes equipped with ring contacts. The electrodes are attached to the camera body, and the movable electrode is attached using current lead and corrugation. Coaxial to the ring contacts on the side of the stationary electrode is a magnetic system containing a permanent magnet and forming a transverse radial axis between the contacts. In a stationary ring contact from the side of its attachment to the electrode, radial grooves are made uniformly spaced around the circumference, in which U-shaped permanent magnets are located, isolated from the fixed electrode and the stationary ring contact. The contact surface of the ring contacts along the axis of the electrodes is located at the level of the plane of the poles of the magnets.

The disadvantage of this vacuum circuit breaker is the low magnetic field strength in the contact gap.

The objective of the invention is: to increase the concentration of the magnetic field in the contact gap, reduce electrical discharge erosion of the contacts and improve the switching characteristics.

The problem is solved due to the fact that the vacuum current switch contains, as in the prototype, an arcing chamber with axial movable and fixed electrodes, the electrodes are equipped with ring contacts. The electrodes are attached to the camera body, and the movable electrode is attached using a current lead and a metal corrugation.

According to the invention, the fixed electrode through the isolation insulator is attached by its current lead to the body of the arcing chamber, and the electrodes are made in the form of disks of non-magnetic material with slots in the form of an Archimedes spiral, and the angles of rotation of the radius of the spiral have the opposite direction, the angle of rotation of the fixed electrode is φ> 0, and the movable electrode has φ <0.

In the proposed vacuum current switch, due to the fact that the electrodes are made in the form of disks of non-magnetic material with slots in the form of an Archimedes spiral, the angles of rotation of the radius of the spiral have the opposite direction, the angle of rotation of the radius of the fixed electrode is φ> 0, and that of the movable electrode is φ <0, the magnetic field concentration between the ring contacts increases. The electrodynamic effect on the electric arc is increasing, which increases its speed of movement between the ring contacts, and consequently, the erosion of the contacts is reduced and the switching characteristics are improved: the circuit breaker service life is extended and the arc interruption time is reduced.

Figure 1 schematically depicts a vacuum current switch and a magnetic system located on a movable and stationary electrode. Figure 2 is a section aa. Figure 3 is a section bb.

The vacuum current switch (figure 1) contains a housing 1, separated by a high-voltage insulator 2, forming an arcing chamber with axial movable 3 and fixed 4 electrodes. On the one hand, the movable electrode 3 is attached to the housing using a current lead 5 and a metal corrugation 6, which separates the vacuum medium of the chamber from the environment. The fixed electrode 4 through the isolating insulator 9 is riveted by the current lead 10 to the body of the arcing chamber. The electrodes 3 and 4 are provided with ring contacts 7 and 8. The electrodes 3 and 4 are made in the form of disks of non-magnetic material, for example, of copper, molybdenum, etc., with slots in the form of an Archimedes spiral, and the angles of rotation of the radius of the spiral have the opposite direction, for a stationary electrode rotation angle φ> 0, and the moving electrode φ <0.

The vacuum circuit breaker operates as follows. With closed ring contacts 7, 8, through the electrodes 3, 4 with slots in the form of a Archimedes spiral, an electric current flows from current leads 5 and 10, which forms a magnetic field radial relative to the axis of the ring contacts in the plane of the connection of the movable 7 and the stationary 8 ring contacts. When the ring contacts 7, 8 are opened between them, an electric arc lights up, while the corrugation 6 is compressed and the tightness of the arcing chamber is ensured. Mechanical efforts on the arc arising from the interaction of the electric current of the arc and the magnetic field directed perpendicular to the arc move it along the contact surface of the ring contacts 7 and 8, pushing it out of the contact gap. Thus, the arc does not locally overheat the contacting surface of the ring contacts 7, 8, which ensures their uniform and minimal wear. Moving, the arc quickly cools and goes out.

Claims (1)

A vacuum current switch containing an arcing chamber with axial movable and fixed electrodes equipped with ring contacts, the electrodes are attached to the chamber body, the movable electrode being attached using a current lead and a metal corrugation, characterized in that the fixed electrode is connected through an isolating insulator with its current lead to the arcing body chambers, electrodes are made in the form of disks of non-magnetic material with slots in the form of an Archimedes spiral, and the angles of rotation of the radius of the spiral have the opposite direction, the angle of rotation of the radius of the spiral is φ> 0 for the fixed electrode, and φ <0 for the movable electrode.

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