BG65525B1 - Contact body - Google Patents

Abstract

The invention relates to a contact body with two separate zones û a high durability zone (1) in the periphery of the contact body made of a material of the following composition: wolfram W from 55 to90 percent; silver AG from 10 to 45 percent; nickel Ni from 0 to 10 percent; cobalt Co from 0 to 10 percent; carbon C from 0 to 8 percent, and a high conductivity zone (2) in the central part of the contact body made of a material of the following composition: wolfram W from 0 to 45 percent; silver AG from 55 to 98 percent; nickel Ni from 0 to 25 percent; cobalt Co from 0 to 25 percent; carbon C from 0 to 10 percent, and molybdenum Mo from 0 to 35 percent, in a pair with a counter-body containing wolfram W, silver AG and nickel Ni.

Description

(54) CONTACT BODY

Technical field

The invention will find application in low-voltage power switches.

BACKGROUND OF THE INVENTION

Specialized contacts are known which are used in circuit breakers for currents of 500 or more amps - working, in tungsten contact pairs - silver 50 / tungsten - silver 50 or tungsten - silver 50 / silver - graphite 5 and tungsten arc dampers - silver 25 / tungsten - silver 25.

These contacts have larger sizes and relatively high material consumption for the contact system.

Universal contacts are known which are used in circuit breakers for currents up to 250 amps, which carry out and interrupt current loads.

The universal contacts are composed of: tungsten - silver 50 / tungsten - silver 50 or tungsten - silver 50 / silver - graphite 5.

The downside of the first universal contacts is the increase in contact resistance over time.

The disadvantage of the second universal contacts is the rapid wear of the contact body in the silver - graphite part 5.

In both types of solutions, the working layer of each individual contact body is made of composite material with the same composition in its entire volume [1, 2, 3, 4].

SUMMARY OF THE INVENTION

The invention relates to a contact body with two distinct zones - an area with increased arc resistance in the periphery of the contact body, made of a material of composition: tungsten W from 55 to 90%; silver Ag from 10 to 45%; Nickel Ni from 0 to 10%; cobalt Co from 0 to 10%; carbon C from 0 to 8% and an area with high conductivity in the central part of the contact body, made up of material of composition: ox fram W from 0 to 45%; silver Ag from 55 to 98%; Nickel Ni from 0 to 25%; cobalt Co from 0 to 25%; carbon C from 0 to 10% and molybdenum Mo from 0 to 35%, in a pair with a counterpart comprising tungsten W, silver Ag and nickel Ni.

Explanation of the annexed figures

Figure 1 is a top view contact body in longitudinal section A-A and in cross-section B-B;

Figure 2 - On / off contact unit. The joint of contacts is at the head of the zone with increased durability 1;

Figure 3 is a contact node with a contact connection in the area with high conductivity.

Embodiments of the invention

An exemplary embodiment of a contact body with two zones for a 250A rated current breaker is shown in FIG. 1. The composition of the material in the durability zone 1 is: tungsten W 63%, silver Ag 35%; Nickel Ni 2%; and the composition of the high conductivity zone 2 is: tungsten W 5%, silver Ag 80%; nickel Ni 15%. The contact body with the two zones is in pair with the counter 3 (Fig. 2), filled in its entire volume with the same composition. Contrail material 3 contains: silver Ag 50%, tungsten W 48% and nickel Ni 2%.

The choice of the optimum material composition of the contact body zones and their dimensioning are determined by the design characteristics of the breaker and its contact system (Figs. 1, 2, 3).

The principle of operation in which the beneficial effect is manifested; is illustrated in FIG. 2 and 3 with the working positions of the contact unit consisting of a contact body with two zones - zone with increased durability 1 and zone with increased electrical conductivity 2, counter 3 and current carriers 4 (Figs. 1,2, 3).

When switched on, the coupling of the contact pair is made in the forehead of the zone of increased resistance 1 of the contact body. Immediately thereafter, the contact joint moves to the high conductivity zone 2, where

65525 Bl release of rated currents. When switched off, the contact joint is moved again to the front of the zone with increased arc resistance 1. There the contacts are separated and the arc ignites and burns (Figs. 2, 3).

Claims (2)

Claims A contact body comprising tungsten W and Ag silver, characterized in that it consists of two separate zones with increased arc resistance (1) and zone with increased electrical conductivity (2), the zone with increased arc resistance (1) is located in the periphery of the contact body and is made up of material of composition: tungsten W, silver Ag, nickel Ni, cobalt Co and carbon C, the area with high conductivity (2) is located in the central part of the contact body and is made of material with composition: tungsten W, silver Ag, nickel Ni, cobalt Co, carbon C and molybdenum Mo. Contact body according to claim 1, characterized in that the zone of high resistance (1) is made of a material having the composition: tungsten W from 55 to 90%; silver Ag from 10 to 45%; Nickel Ni from 0 to 10%; cobalt Co from 0 to 10%; carbon C from 0 to 8%; the area with high conductivity (2) is made of material of composition: tungsten W from 0 to 45%, silver Ag from 55 to 98%, nickel Ni from 0 to 25%; cobalt Co from 0 to 25%, carbon C from 0 to 10% and molybdenum Mo from 0 to 35%.