JPS6314432Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a safety device that utilizes deformation of a metal case to interrupt an electric circuit.

Configuration of the conventional example and its problems Figures 1 and 2 show the conventional example.
is a conductive member that constitutes the cut-off part of the safety device, and copper foil or copper plate is used. Reference numeral 2 denotes an insulating plate mounting bracket; 3 an insulating plate installed oppositely on the inner surface of the metal case 4 by the insulating plate mounting bracket 2, supporting the conductive member 1; Reference numeral 6 indicates a fixing pin for fixing the insulating plate 3 to the mounting bracket 2, and 7 indicates lead wires connected to both ends of the conductive member 1.

The operation of this safety device is as follows. That is, when the capacitor is destroyed, the metal case 4 bulges and deforms due to the gas pressure caused by the generation of decomposed gas, the two insulating members 3 are relatively separated, and the conductive member 1 is moved to its weak point 1a (center section),
The current flow between both lead wires 7, 7 is cut off, and power supply to the capacitor is stopped.

However, although such safety devices do not cause much of a problem when used at low voltages, when used at high voltages, conductive impurities, metal powder, etc. can cause dielectric breakdown between the mounting bracket 2 and the conductive member 1. The problem was that it caused

Purpose of the invention The purpose of the invention is to provide a safety device that can reduce dielectric breakdown when used under high voltage.

Structure of the Invention The safety device of this invention prevents dielectric breakdown between the insulating plate fitting and the conductive member by coating the surface of the insulating plate fitting with a resin-impregnated glass woven fabric.

DESCRIPTION OF EMBODIMENTS An embodiment of this invention is shown in FIGS. 3 and 4. In the figure, reference numeral 5 denotes a glass woven cloth impregnated with epoxy resin, which is coated on the surface of the insulating plate mounting fitting 2. The method for attaching the woven glass fabric 5 is to attach a woven glass fabric impregnated with an epoxy resin onto the mounting fitting 2, and then heat-cure and bond the fabric. The thickness of this glass woven fabric 5 is desirably set to 0.5 mm or more.
The rest of the configuration is the same as that of the conventional example, so the same parts are given the same reference numerals and the explanation thereof will be omitted.

As a result of covering the surface of the mounting bracket 2 with the epoxy resin-impregnated glass fabric 5 serving as an insulating member, dielectric breakdown between the conductive member 1 and the mounting bracket 2 can be prevented even under high voltage.

FIG. 5 shows a metal case 4 and a conductive member 1 in capacitors incorporating a conventional safety device and a safety device of the present invention.
1000VAC per minute from 10000VAC applied voltage during
The dielectric breakdown voltage is displayed as a blot when the voltage is increased. In the same figure, the left side shows the glass woven fabric with a thickness of 0.5 mm or more, the center shows the conventional example, and the right side shows the glass woven fabric with a thickness of 0.5 mm or more.
Indicates the case of 0.5mm or less. As can be seen from this experimental example, when the mounting bracket 2 is covered with the glass woven cloth 5, the breakdown voltage is improved compared to the conventional example, and especially when the glass woven cloth is set to a thickness of 0.5 mm or more, the breakdown voltage was increased to over 40,000V, and the performance was significantly improved. In addition, in the above experiment, the glass woven fabric 0.5 mm
The reason why variations in breakdown voltage are observed in the following cases is thought to be due to the formation of pinholes in the glass woven fabric 5. When the diameter is 0.5 mm or more, variations in breakdown voltage no longer occur because the pinholes disappear. This is thought to be due to the

In addition, as a method of preventing dielectric breakdown between the conductive member 1 and the mounting bracket 2, a method of covering the mounting bracket 2 with a polypropylene sheet or a polyethylene sheet may be considered, but in such a method, the gap between the sheet and the mounting bracket 2 Electrically conductive particles, metal powder, etc. pass through the holes and pinholes, causing dielectric breakdown at the mounting bracket 2 due to creeping discharge.

Effects of the invention This invention has the effect of reducing dielectric breakdown when used under high voltage.

[Brief explanation of drawings]

Fig. 1 is a vertical sectional view of the conventional example, Fig. 2 is a horizontal sectional view thereof, Fig. 3 is a vertical sectional view of an embodiment of this invention, Fig. 4 is a horizontal sectional view thereof, and Fig. 5 is a breakdown voltage. It is a characteristic diagram. DESCRIPTION OF SYMBOLS 1... Conductive member, 2... Mounting bracket, 3... Insulating plate, 4... Metal case, 5... Glass woven fabric, 7...
…Lead.

Claims (1)

[Claims for Utility Model Registration] (1) A metal case, a pair of insulating plates facing each other on the inner surface of the metal case, one end fixed to the insulating plate and the other end fixed to the inner surface of the metal case. a pair of insulating plate mounting brackets; a conductive member that is fixed between the two insulating plates while being separated from the mounting bracket and is cut at the center due to the bulging deformation of the metal case to cut off electricity; and both of the mounting brackets. A security device comprising a resin-impregnated glass woven fabric coated on top of each other. (2) The security device according to claim (1), wherein the resin is an epoxy resin, and the glass woven fabric has a thickness of 0.5 mm or more.