DE202007002275U1 - Varistor e.g. voltage dependent resistor, has ceramic crystal with main body provided with electrode layers on both sides, and current conductors with one end linearly welded on exterior of electrode layers of crystal - Google Patents

Abstract

The varistor has a ceramic crystal (2) and current conductors (3), which are made up of copper. The crystal has a main body (21) provided with electrode layers (22) on both sides, where one end of the conductors is linearly welded on the exterior of the electrode layers of the crystal. The main body serves for the assembly of the varistor, and the conductors consist of interweaved wires or wire meshes.

Description

The The present invention relates to a varistor.

Especially This varistor is designed with a current conductor that is linear on the outside of a ceramic crystal is welded. It is advantageous that The varistor is not easily damaged and is more reliable.

There Varistors generally respond quickly, their resistance to overvoltages almost instantaneous is very small and they have a high stability for the line voltage and have a symmetrical current / voltage characteristic, a varistor is usually electrically connected between the power source and an overload. If from the power source is therefore not supplied with additional electrical power, the varistor is switched on and the voltage peak is recorded, so that the varistor is not damaged by the overload current, in order to protect against voltages or other sources of To achieve high voltages.

1 shows a perspective view of a conventional varistor. The varistor 1 is made of a ceramic crystal 11 , two electrode layers 12 and two plate conductors 13 built up. On both sides is the ceramic crystal 11 each with an electrode layer 12 Mistake. On each outer layer of the electrode layer 12 is a plate conductor 13 welded. On the outside, an epoxy resin is applied for the insulation and the vibration seal, whereby in principle the grain boundary property of the ceramic crystal 11 is applied to provide protection against heating on the two terminals in the event of transient overvoltage, which is generated by current voltage spikes. Therefore, the electric current must be passed through the main body of the ceramic crystal to convert these voltage spikes into heat energy.

at However, the following occur when using the above-mentioned varistor Disadvantages: (1) Since the plate current conductors have a certain size, they have a certain internal tension. When welding the Plate conductor on the outside the electrode layer, the varistor inside by the internal Voltage and heat from the heat generated by high voltages is damaged become. This is not from the outside which further increases the risk of fire. (2) In general, the plate conductor is made of a copper material with a good quality produced. When the temperature of the plate conductor and the ceramic crystal is increased because of high voltages, because this is also because the plate conductor has a higher thermal expansion coefficient As the ceramic crystal has, the ceramic crystal can through The expansion of the plate conductor can be easily damaged.

With The development of a new varistor to the disadvantages of conventional embodiment be eliminated.

The The main object of the present invention is to provide a durable and reliable Construction of a varistor.

These Task is with a varistor with the features of claim 1 solved. Advantageous developments of the inventions to the invention varistor are the subject the dependent claims.

One Varistor according to the invention thus consists of a ceramic crystal and of several conductors. The ceramic crystal consists of a main body and an electrode layer both sides of this main body. One end of the conductor is linear on the outside of the electrode layer for the ceramic crystal welded while the other end of this Conductor is connected to a terminal.

With The above technical embodiment can be used with the present invention the disadvantages of conventional embodiment be eliminated, the embodiment of the invention more durable and reliable is.

The Invention will be described below with reference to an embodiment and the drawing described. In the drawing show:

1 a perspective view of a conventional varistor;

2 Top view of a varistor according to the invention;

3 a perspective view of a conductor, which is welded on an electrode layer on the main body;

4 a view of another conductor, which is welded on an electrode layer on the main body; and

5 a sectional view of the epoxy coating and the outer casing of the varistor according to the invention.

As in 2 and 3 is shown, is an inventive structure of a varistor, ie span voltage-dependent resistance, made of a ceramic crystal 2 and from several conductors 3 built up.

The ceramic crystal 2 consists of a main body 21 , wherein this on both sides, each with an electrode layer 22 is provided. The main body 21 used for mounting (folding) of the varistor.

One end of the power line 3 is linear on the outside of the electrode layer 22 for the ceramic crystal 2 welded on while the other end of this conductor 3 with a connection terminal 31 connected is. The conductor 3 can be made of interwoven wires or a wire mesh (as in 4 shown) or from conventional copper wires (as in 3 shown) executed.

5 represents the assembly described above. The outside of the improved construction of the varistor is epoxy resin 4 coated and comes with an outer cover 5 jacketed. As in further 5 is shown, is the terminal 31 for the conductor 3 electrically connected to the protected circuit or to the device (not shown in the drawing). When an abnormal voltage occurs, the varistor is activated and the current can pass through the electrode layer 22 are passed, whereby the heat generated by the energy of the voltage spike is distributed so as to protect the circuit or the device.

Further, with respect to the present invention, it can be emphasized that one end of the current conductor 3 linear to the outside of the electrode layer 22 is welded on. Of course, one end of this conductor 3 in a vortex form (wound) and on the outside of the electrode layer 22 (like in the 4 shown) or welded in a linear beam shape to achieve the same effect. Other modifications that can achieve the same effect are possible.

1

varistor (Voltage-dependent Resistance)

11

ceramic crystal

12

electrode layer

13

Plate conductor

2

ceramic crystal

21

main body

22

electrode layer

3

conductor

31

terminal

4

epoxy resin

5

outer envelope

Claims (5)

Varistor constructed from a ceramic crystal ( 2 ) and several conductors ( 3 ), one end of the conductor ( 3 ) linearly on the outside of this ceramic crystal ( 2 ) is welded. Varistor according to Claim 1, characterized in that the current conductor ( 3 ) is made of copper. Varistor according to Claim 1, characterized in that the current conductor ( 3 ) consists of interwoven wires or a wire mesh. Varistor according to Claim 1, characterized in that one end of the conductor ( 3 ) in a vortex form and on the outside of the electrode layer ( 22 ) is welded. Varistor according to Claim 1, characterized in that one end of the conductor ( 3 ) in a linear beam shape and on the outside of the ceramic crystal ( 2 ) is welded.