JPH05190064A - Electric contactor - Google Patents

Abstract

PURPOSE: To obtain higher pressure in a spraying volume part to surely break a low current in breaking a low current, by providing a metallic tube to which the protruded part of an insulating material is fixed to the tip. CONSTITUTION: A metallic tube 8 has an end having a spread for retaining a contact tube 9 for constituting an movable arc contact, and a finger piece of a contact 10 for forming a movable permanent contact; and a portion 9A, made of material having resistance to the action of an arc, is provided on the end in the tube 9. A tip part 12 made of insulating material is provided in the end part of the tube 9, and is fixed to the tube 9 by a spring stopper, etc. In separating the arc contact arcing is made, gas in a spray volume part 6 is heated, and pressure in the inside is increased; but the volume part 6 remains as it was actually closed even if the portion 9A is extracted from the bottle neck part of a nozzle 5. Consequently, pressure in the volume part 6 is successively increased to surely breake a low current (e.g. a rated current as a low current opposite to a high current such as a short circuit).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to electrical contacts that can be used to construct arc contacts for medium or high voltage circuit breakers.

[0002]

2. Description of the Prior Art In an automatic blow-type circuit breaker, the heat generated by the arc that appears when the arc contacts are separated is used to heat a volume of gas called a blow volume or expander. It has been known. This volume is delimited at one end by a spray nozzle, and when the interrupted current flow passes through zero, the gas in the spray volume expands as it traverses the constriction of the nozzle and blows into the arc. Attach.

The effect of spraying is that, especially for spraying on an arc which occurs at the interruption of a low current (for example the current corresponding to the rated value of the current at the point where the breaker is inserted), the spray volume It was confirmed that the pressure increase in the section was insufficient and was not sufficient.

[0004]

SUMMARY OF THE INVENTION It is an object of the invention to improve the contacts so as to obtain a greater pressure in the spray volume, especially for low current interruptions.

[0005]

This object is achieved by the contact according to the invention, which can be used as a moving arc contact in an automatic blast circuit breaker including a blast volume and a blast nozzle. This contactor is characterized by being constituted by a metal tube having a tip of an insulating material fixed to the tip.

[0006] The tip of the present invention is described in French Patent Application No. 2
Not to be confused with the insulating parts described in 389 219. In this document, the insulating component is placed inside the fixed arc contact of the circuit breaker to allow arc switching on the annular electrode connected to the fixed arc contact.

In the present patent application, the breaker does not include any annular electrodes, with the tip located at the tip of the moving arc contact.

[0008]

The invention will be better understood by describing the embodiments with reference to the accompanying drawings.

The shut-off chamber, which is partially shown in FIG. 1 in axial section, consists of an airtight envelope 1 (made of porcelain in classical circuit breakers, made of metal in circuit breakers called grounded metal casings) of several bars. A gas having good dielectric properties such as sulfur hexafluoride is filled under pressure.

An assembling device is fixed inside the shut-off chamber, which is electrically connected to a first outlet (not shown) and holds a first metal pipe 3 forming a fixed main contactor. 2, a second metal tube 4 coaxial with the first tube and forming a fixed arc contact, and for example polytetrafluoroethylene (eg known as Teflon®).
And an insulating spray nozzle 5 made of metal. The tube 4 comprises at its end a portion 4A made of a material resistant to the action of an arc, for example tungsten carbide.

Volume 6 defined by tube 2 and nozzle 5.
Constitutes the blast volume of the circuit breaker.

The tube 4 can be closed (single spray) or open (double spray) at its internal end.

The circuit breaker mover includes a metal tube 8 electrically connected to the second outlet by a sliding contact, not shown. The tube is connected to an insulated operating rod (not shown).

The tube 8 has a flared end for holding the contact tube 9 which constitutes the movable arc contact and the finger piece of the contact 10 which forms the movable permanent contact. The tube 9 is provided at its end with a portion 9A made of a material resistant to the action of an arc.

The tube 9 has a tip end made of an insulating material at its end.
This tip, which comprises 12 and extends beyond the portion 9A, is fixed to the tube 9 by screwing or snapping.

The tip material is advantageously polytetrafluoroethylene. This choice of material is advantageous because it produces a fluorine-containing vapor that facilitates arc interruption when it is heated by the arc. The material can be filled, for example with glass fibers or resin.

When the circuit breaker is in the engaged position, current flows through the tube 2, the contact 3, the finger strip 10 and the tube 8.

When the breaker is removed, the main contacts 3 and 10
Are separated and current is carried by the arc contacts 4 and 9.

In the case of arc contact separation (FIG. 2), the arc 15 flies between the arc contacts and the gas in the volume 6 is heated, thereby increasing the pressure inside the volume.
Due to the tip 12, the volume 6 remains substantially closed even if the distal end 9A of the movable arc contact 9 comes out of the constriction of the nozzle. In this way, the pressure in the volume 6 continues to pass because the gas in this volume is almost unable to escape through the narrow annular passage existing between the tip 12 and the constriction of the nozzle. To increase.

The volume 6 is open and the blown gas escapes across the constriction of the nozzle only when the tip 12 has passed the constriction of the nozzle (FIG. 3). In the volume 6, it is possible to calculate the length of the tip 12 taking into account the speed of displacement of the contact so as to obtain an overpressure which can obtain a cut-off at the time of zero passage of the current flow. is there.

Since the present invention maximizes the effect of spraying, it ensures the interruption of low currents (for example, rated currents as opposed to strong currents such as short circuits).

By implementing a fixed arc contact in the form of a tube, a double spray is obtained in the open circuit of the circuit breaker, as indicated by the arrow in FIG.

The present invention finds application in medium or high voltage circuit breakers of conventional or grounded metal casing.

[Brief description of drawings]

FIG. 1 is a partial axial cross-sectional view of a shutoff chamber of an automatic circuit breaker of the present invention, showing a state of engagement.

FIG. 2 is a vertical cross-sectional view similar to FIG. 1, showing a state after the arc contactor has been separated but before spraying on the arc.

FIG. 3 is a vertical sectional view similar to FIG. 1, showing a state at the time of arc blowing.

[Explanation of symbols]

 1 Outer Cylinder 2 Metal Tube 3 Metal Tube (Fixed Main Contact) 4 Metal Tube (Fixed Arc Contact) 5 Nozzle 6 Spray Volume 8 Metal Tube 9 Metal Tube (Movable Contact) 10 Movable Permanent Contact 12 Tip

Claims (5)

[Claims] 1. A blast volume and a blast nozzle, characterized in that the electrical contact is constituted by a metal tube which penetrates the nozzle and has a tip made of an insulating material fixed to its end. An electric contact that can be used as a movable arc contact of an automatic blow-type circuit breaker. 2. The electrical contactor according to claim 1, wherein the material of the tip portion and the nozzle is polytetrafluoroethylene. 3. The electric contactor according to claim 1, wherein the projecting end portion is fixed to the pipe by screwing. 4. The electric contactor according to claim 1 or 2, wherein the projecting end portion is fixed to the pipe by fitting. 5. The electric contactor according to claim 2, which is filled with polytetrafluoroethylene.