Siemens Aktiengesellschaft

Wilfried Kuhl

Ruediger Hess

Reiner Mueller

Horst Kippenberg

Joachim Grosse

Heinrich Haessler

Leonhard Klug

Wolfgang Schilling

Wolfgang Schlenk

Ernst-Ludwig Hoene

Edwin Gemmel

Heinz-Helmut Schramm

Peter Trentin

Heribert Weber

Bernd Rost

Contact arrangement for vacuum switches with axial magnetic fields

To check the presence of operating vacuum in vacuum switches, high voltage can be applied between the contacts at a given contact spacing and the dielectric strength can be tested. According to the invention, the procedure for vacuum monitoring is that a contact spacing (h) below the nominal stroke of the vacuum switch is selected and that the X-radiation generated at this contact spacing (h) and high voltage (U) in vacuum due to the field electron emission between the contacts by the contact surfaces acting as anode is acquired and evaluated as proof of the presence of operating vacuum inside the switching tube. This method can preferably be applied to encapsulated vacuum switching tubes, in particular to SF.sub.6 -insulated switching facilities. Associated with the vacuum switching tube (15) in the associated equipment is an X-ray detector, preferably a Geiger-Muller counter, which is connected to the high-voltage unit (25) via an evaluating circuit (30 to 50) which serves for the determination and indication of the operating vacuum and shuts off the high-voltage unit (25) to minimize the X-ray dose. Due to the X-ray emission, which is stopped long before reaching impermissible values, the presence of vacuum can be positively verified.

Method and equipment for vacuum monitoring in vacuum switching tubes

This invention relates to a new use of a fused material of copper and chrome as a contact material for use in vacuum contactors. In addition, the invention relates also to the contact material itself and to the method of its fabrication, as well as for special contact arrangements in the vacuum contactors. The invention shows a whole new, unsuspected range of application for the above fused materials. Up to now, contactors normally used material based on tungsten and copper which were first sintered and then immersed. It has now been experimentally shown that fused materials of copper and chrome, particularly after being reshaped, are very well suited as a contact material for vacuum contactors. Furthermore, in contact pieces of said fused material, methods are provided for additional additives to be precisely inserted by localized alloying, diffusion, or related techniques.

Use of a fusion material of copper and chrome as the contact material

Contact pieces for vacuum switches with axial magnetic field are designed, for example, as pot type contacts with codirectional slotting which contain in each instance a disk-shaped contact body of contact material and have an arrangement for the suppression of eddy currents. Conventional techniques for this purpose typically involves the cutting of radial slots in the contact bodies. In accordance with the invention, each contact piece (10, 110, 210) comprises a plurality of discrete elements (11, 111, 211) which are so arranged on the concrete carrier (2) that their edges (12, 13; 112, 113; 212, 213) form joints (25, 125, 225) and thereby define conductivity jumps for the suppression of the eddy currents. Specifically the discrete segments (111, 211) are produced by reshaping a cylindrical blank (100) of circular cross section into a semi-finished product of circular sectorial cross section.

Contact arrangement for vacuum switches with axial magnetic field, and

A device for measuring the internal pressure of an operationally built-in vacuum switch which comprises a vacuum switching tube having a switching chamber and switch contacts as well as an associated drive for the contacts. For the measurement of the pressure, a cold-cathode discharge (so-called Penning effect) having crossed electric and magnetic fields is used, wherein the electric field is applied, for instance, between at least one of the switch contacts and a metallic wall of the switching chamber or a condensation shield disposed in the chamber and permanent magnets are used for generating the magnetic field. The permanent magnets are realized in the form of rods and have pole pieces formed such that the pole pieces encircle the switching chamber. A magnetic field is formed which is applied directly in the longitudinal direction to a circumferential section of the cylindrical switching chamber. In order to measure the pressure inside the vacuum switching tube built into a switching installation, the voltage drop across a resistor disposed in series with a d-c source and the switch is measured. The voltage drop corresponds to the ionization current, which is dependent on the gas pressure in the chamber. The pole pieces of the permanent magnets extend around the switching chamber and fix the magnets around the switching chamber during the measurement. The sensitivity range of the measurement can be influenced by the number of permanent magnets used.

Device for measuring the internal pressure of an operationally built

A vacuum switch for the low-voltage range, in particular, a low voltage contactor, comprising a vacuum switching tube having a switching chamber and a first contact rigidly arranged therein and a lead-in pin movable relative thereto having a second contact, wherein the vacuum switching tube has an insulating member which is surrounded on the vacuum side at least partially by shielding. The shielding is arranged as a concentric hollow cylinder and the insulating member comprises a ring shaped member, preferably of ceramic. The axial length of the shielding cylinder is at least 1.5 times that of the ring. A vacuum switch having a short insulating path thus can be constructed cost-effectively and which has the capability for a high number of switching cycles.

Vacuum switch for the low-voltage range, especially a low-voltage

Contact arrangement for vacuum switch in which one of two contacts is movable relative to the other in the axial direction of the contacts and is designed as a recessed contact. According to the invention, a condensation plate with a diameter greater than the inside diameter at the rim of the recessed contact is provided between the other contact and its current lead. The sidewall of the recessed contact forms a guide ring for the metal vapor, a substantial part of which condenses on the condensation plate.

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Wendelstein, Germany

Wilfried Kuhl