WO2004072992A1

WO2004072992A1 - Varistor protective insertion

Info

Publication number: WO2004072992A1
Application number: PCT/SI2004/000006
Authority: WO
Inventors: Janez Alic
Original assignee: Alfa & Omega D.O.O.
Priority date: 2003-02-12
Filing date: 2004-02-10
Publication date: 2004-08-26
Also published as: SI21153A

Abstract

The object of the invention is the varistor protective insertion, composed of a varistor, a current and a thermal fuse, being used in an electric device protection system against excess voltage strokes (lightning) and increased currents. The varistor protective insertion under the invention comprises of two electrodes (2, 3) of the varistor provided on the inner and outer part of the isolative body (1), and set inside the isolative body (1) a current protection (4) and a thermal protection (5), both enclosed in extinguishing material (6).

Description

VARISTOR PROTECTIVE INSERTION

The object of the invention is the varistor protective insertion, composed of a varistor, a current and a thermal fuse, being used in an electric device protection system against excess voltage strokes (lightning) and increased currents. The invention is classified to class H 01 C 07/10 of the international patent classification.

The technical problem, which the hereby proposed construction of the varistor protective insertion successfully resolves, presents the construction of such an element, that will swiftly react to electrically harmful strokes and could be built in already existing electrical installation casings.

The known solutions of protective elements for electric devices and electronic circuits against excess voltage strokes, increased electric currents or overheating, resolve the individual protection partially. Thus, there exists a variety of differently designed varistors, which protect on the first position of the electric device against excess voltage, different versions of protections against an increased current through the circuit on the second position and protective elements, that cut out the charging at increased temperature on the third position. All these elements are constructed only for protection of an abnormal condition on their respective position. The weakness of protective elements provided in such a manner lies in the slow reaction of mutually dependent parameters. In this way it can come to certain breakdowns of the elements alone, as well as the protected devices.

The varistor protective insertion under the invention comprises of two electrodes of the varistor provided on the inner and outer part of the isolative body, and set inside the isolative body a current and a thermal protection, both enclosed in extinguishing material.

The invention is explained in detail on the basis of the realized example and the belonging images, from which:

Figure 1 exhibits an electric scheme of the varistor protective insertion under the invention;

Figure 2 exhibits a schematic representation of the varistor protective insertion under the invention in crosscut;

In Figure 2 a varistor protective insertion under the invention is schematically represented. It consists of an isolative body 1 , which is provided with two electrodes 2 and 3 of the varistor on the inner and outer part, and the isolative body 1 comprises of a current protection 4 and a thermal protection 5, both enclosed in extinguishing material 6, while both sides of the isolative body 1 are provided with incoming contacts 7 and outgoing contacts 8 and when necessary also with intermediary contacts 9.

On a part of the outer and inner surface of the body 1 , electrodes 2 and 3 of the varistor are provided in a well-known manner. The incoming contact 7 and the outgoing contact 8 are represented by metal parts, which are placed on both sides of the body 1. When necessary, an intermediary contact 9 is provided on one side. Connected between the incoming contact 7 and the outgoing contact 8 there are the current protection 7, e.g. with a thinner form of a conducting wire, and the thermal protection 8, e.g. a joined wire with the material, that enables an interruption in the connection at increased temperature.

The form of the body 1 may be adapted in such a way, that makes the usage of the varistor protective insertion under the invention feasible in all standard casings of protective elements. In this way, practically using a single protective insertion, the protection on all three positions is achieved, which on the one side enables swift reaction to electrically harmful strokes, and on the other hand a rationalisation in dimensioning and the number of casings of protective elements is achieved.

Claims

PATENT CLAIM

1. Varistor protective insertion, characterized in that, two electrodes (2, 3) of the varistor are provided on the inner and outer part of the isolative body (1 ), and the isolative body (1 ) comprises of a current protection (4) and a thermal protection (5), both enclosed in extinguishing material (6), meanwhile incoming contacts (7) are provided on one side of the isolative body (1 ), outgoing contacts (8) on the other side of the isolative body (1 ), and when necessary an intermediary contact (9) is also provided.