JPS5895933A - Surge absorbing element - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a surge absorption element that can minimize leakage current generated only by a ZnO-based varistor and has surge response characteristics similar to those of the ZnO-based varistor.

The ZnO-based varistor has ZnOt as the main component and Bi! 's
A pair of electrodes is formed on the resulting sintered body by adding trace components such as BaO, mixing them uniformly, and sintering them in the air at a temperature of 800 to 1500°C after pressure molding. Lead III was connected to the main body, and the entire body was coated with resin. ZnO type varistor has voltage to electric R11i
The nonlinearity in l characteristic is extremely large, and when the voltage-current characteristic of a varimeter is expressed as I=kV, α=3 to 7 for a normal varistor, whereas Fiff=25 to 50 for a ZnO-based varistor. It is known that it exhibits excellent nonlinearity, with some having a value of 50 or more, and this property is used for surge absorption, etc.

However, due to the large non-linearity in the voltage-current characteristics mentioned above, ZnO-based varistors leak current when a voltage is applied, and when used for a long time with constant voltage applied, the voltage-current The deterioration of the R'lli properties progresses, leading to vcFi destruction, resulting in a short-circuit state, and there is a risk of thermal runaway.

The present invention eliminates the above-mentioned danger by minimizing the leakage current without impeding the excellent surge response characteristics of the ZnO-based varistor, and provides a surge absorption element that prevents the ZnO-based varistor from deteriorating. The purpose is to

The present invention was developed as a result of various studies to achieve the above object, and consists of a discharge tube having a microgap of 10 to 100 IRn and filled with an inert gas such as Ar + Ne, and a ZnO-based varistor connected in series. This is a surge absorption element configured by connecting the two.

] A gas-filled discharge tube with a microgap of 0 to 100 pm is made by attaching a conductive thin film to the surface of an insulator, forming a microgap of 10 to 100 pm in the chain conductive thin film, and using this microgap to connect the thin film. Divide it into multiple pieces, and connect the electrically conductive thin layers at both ends of the divided pieces to each other. , are fixed to each other, electric wires are electrically connected to each electrode, and the space between the electrodes is covered with an insulating coating material, and an inert gas such as K Ar + Ne is filled in the discharge tube. .

FIG. 1 is an equivalent circuit showing an embodiment of the present invention, in which 1t
flO~100I! The gas-filled discharge tube has a microgap of m, and 2 is a ZnO-based varistor.

Hereinafter, in the example of the surge absorption element shown in Fig. 1, a surge absorption element using a gas discharge tube with a micro gap with a discharge starting voltage of 220V and a ZnO-based varistor with a varistor voltage of 220V will be described. The effects of the present invention will be explained by taking as an example a case where a voltage is applied to both ends A and H of.

Both ends A of the surge absorption element shown in Fig. 1, BKAC100
When a voltage of V is applied, the leakage current value Fi becomes 0.057 μA. On the other hand, when AC 100V is applied only to the ZnO system with a varistor voltage of 220V, the leakage current value is 29
．． It becomes 16μA.

Therefore, by connecting in series a gas-filled discharge tube with a microgap of lθ ~ 1,00 μm and a discharge starting voltage of 220 V to a ZnO-based discharge tube with a varistor voltage of 220 V, it is possible to The leakage current of the varistor can be extremely reduced to about 2/1000.

Next, when a full DC voltage is applied to both ends A and B of the surge absorbing element in FIG. 1 and the DC discharge starting voltage Vst- is measured, V~
The engineering characteristic diagram is shown in Figure 2.

As shown in Figure 2, the apparent DC discharge starting voltage of the surge absorbing element in Figure 1 is 440V.
0v and the DC discharge starting voltage of 220v of a gas-filled discharge tube having a microgap of 10 to 100 μm.

V~ when DC voltage is applied only to ZnO varistor
The engineering characteristics diagram is shown in Figure 3.

Further, the VI characteristic diagram of a gas-filled discharge tube having a microgap of 10 to 100 μm and a DC discharge starting voltage of 220 V is shown in FIG. From FIG. 4, it can be seen that glow discharge occurs at 160V.

Furthermore, when a DC voltage is applied to both ends A and BK of the surge absorbing element shown in Fig. 1, the difference between 220 V (varistor voltage of the ZnO-based varistor) and 380 V (varistor voltage of the ZnO-based varistor and glow discharge voltage of the microgap discharge tube) An oscillation phenomenon as shown in Fig. 5 is observed in the range of
It is approximately the sum of the varistor voltage of the system varistor and the DC discharge starting voltage of a gas-filled discharge tube having a microgap 1 of 10 to 100 μm.

Next, the surge response characteristics will be explained. The characteristic diagram of y- when a surge voltage of 3 KV rising for a time of 0.1 μ3 is applied to the surge absorbing element of the present invention, a gas-filled discharge tube having a microgap of 10 to 100/ffi, and a ZnO-based varistor is shown below. , as shown in FIGS. 6, 7, and 8, respectively.

From the figure, the discharge starting voltage when applying a surge voltage is
It can be seen that the voltage is the same in both cases, 1.2 KV.

Further, from FIGS. 6 and 8, the surge response characteristics when a surge voltage is applied to the surge absorbing element of the present invention are similar to the surge response characteristics when a surge voltage is applied only to the ZnO-based varistor.

As described above, the present invention is designed to minimize leakage current of ZnO type (risk) when a full voltage is always applied to a surge absorption element utilizing ZnO type non-linearity. ) (completely prevents the deterioration of the risk, while ZnO-based) (does not inhibit the surge characteristics of the risk, so it can be used as an excellent surge absorbing element.

[Brief explanation of drawings]

FIG. 1 is an equivalent circuit diagram of an embodiment of the present invention, and FIG. 2 is an equivalent circuit diagram of an embodiment of the present invention. Figures 3 and 4 are A-B, C-B, and A of Figure 1, respectively.
V~I4I characteristic diagram when DC voltage is applied to ~C, 5th
The figures are a characteristic diagram of V- which shows an oscillation lump in the range of 220v to 380VO in Fig. 2, Figs. 6 and 7. Figure 8 shows 0.1. It is a characteristic diagram of V when a rising surge voltage of 3 KV is applied between μ8 and A to B, A to C2C to BK in FIG. 1. 1... Microgap discharge tube 2... ZnO varistor, A, B, C... Each terminal 1st
Figure S Figure 4 Time t (Ps)

Claims (1)

[Claims] 1 Ar with 10-100PTR microgap tube
A surge absorption element formed by connecting a discharge tube filled with an inert gas such as tNe and a ZnO-based varistor in series.