SI20781A - Universal surge arrestor device - Google Patents

Abstract

Subject of the invention refers to the field of surge protection of varistor elements by universal surge arrestor device, consisting of a supporting cover (8) with built-in electrode (10) and switching electrode (14). By switching the arrestor spring (6) of special shape the electrode disconnects the protected varistor from the network in cases of damage following overheating. It helps to eliminate problems connected to the power supply and can also solve problems of protecting other devices connected to the same circuit, and exposed to overvoltages. Inside the supporting cover (8) there is an additional signal electrode (12) which provides the universal surge arrestor with the possibility of signalling the error.

Description

UNIVERSAL VOLTAGE PROTECTION

The subject of the invention relates to the field of overvoltage protection of varistor elements with universal overvoltage protection device, which eliminates the problems of supplying electricity in the degradation of varistors and solves the problem of protection of other devices connected to the same electrical circuit exposed to overvoltages.

The invention belongs to the international patent classification in H02H7 / 09

The varistor is known to be a variable resistor that changes its resistance depending on the electrical voltage acting on it. Varistors are also subject to aging or their characteristics change when connected to the mains. The varistor leaves a larger permanent current after an electrical break, which means that the possibility of damaging the electrical equipment in the surrounding area increases, and in the event of major degradation of this element, a fire may occur. Even in case of overvoltage with prolonged operation on the element, the varistor may overheat or explode and damage the circuit in which it is integrated, adjacent elements and device.

The essence of the problem is how, through the affordable and widespread use of universal overvoltage protection devices, based on the use of at least one varistor arrester, it is possible to overcome the problematic currents of the current so far, and also to indicate defects in the event of degradation or reduction of the basic quality parameters of the protection element as also, with better control over the operation of the overvoltage element, enable remote fault signaling.

Several manufacturers have addressed this problem so far. The solutions of the following manufacturers are known: Phoenix (Germany), Citel (France), Iskra Zaschita (Slovenia).

So far, this problem has been solved with a thermal fuse that had the function of electrical disconnection from the mains. In practice, they used the option of mounting a metal or plastic wall and printing a fuse against the wall of the varistor.

In practice, however, it has been realized in the prior art that, with a varistor, a series-coupled thermal fuse, at large electrical overloads (such as lightning strikes or overloads with a longer operating time), due to the relatively large amount of released energy and since then it no longer served its purpose. Additional problems arise because the metal parts of the fuse are welded, despite the short-circuit current, the fuse does not react, nor is it able to play its function in the event of thermal overload.

There are also known solutions where the disconnection of the varistor arrester is performed via a so-called hot electrode, whereby the reaction rate is slower due to the incorporation of the varistor element into the protective housing.

These designs are expensive and are only suitable for narrowly profiled safety features.

The invention relates to the field of protection of varistor elements and to overcome the problematic low discharge currents and to enable better control over the operation of the overvoltage element by indicating defects in case of degradation or lowering the basic quality parameters of the protection element and remote signaling of defects. In order to recognize that every varistor arrester that protects the power circuits needs some protection against thermal stress due to the degradation of the varistor, and that this function is performed by an invented protective device designed to be mounted on varistors (regardless of the nominal voltage) of all world manufacturers with easy connection through special contact, it can be called universal.

The solution provided by the described invention has no disadvantages of the present embodiments, since it replaces the known solutions so far with a universal protective device that is attached to the varistor.

The device is useful in many applications and is available in many combinations, in an alternative embodiment comprising at least two varistors, each of which is provided with a carrier cover 8 and one disconnecting spring 6 each.

It is also possible to install several combinations simultaneously.

The universal overvoltage protection device solves the above problem by attaching the device to the varistor by simply mounting it to the fixed legs of the varistor, which is at the same time supporting the housing. The point is that this connection continues through the flat body of the housing, which at the same time acts as an absorption path for heat dissipation, which is released in the event of a varistor failure. Further, a disconnect mechanism with a mounting disconnect spring 6 of special meandric shape is rigidly mounted in the carrier cover 8. This design helps to maintain the suspension of the trip contact, which ensures a high degree of suspension even after a certain installation time, by eliminating the effects of aging by design, thereby increasing the reliability of operation. The disconnect mechanism is soldered to the absorbent plate with a low-temperature solder, thereby disconnecting the varistor arrester at a relatively low temperature, due to the fact that it also protects the elements near the varistor from the harmful effects of high temperature.

The supporting cover 8 housing the electrodes is made of transparent, non-conductive material, characterized by a high degree of self-extinguishing (V-O), which is a condition for the device to meet safety standards. For better transparency in the event of a disconnect, there is a polished window in the carrier cover 8 that provides a direct view.

If necessary, in the case of remote fault signaling, an additional contact connector is also provided in the carrier cover 8, which is contacted by a tripping contact in the event of a varistor arrestor failure.

The advantage of the described solution is also in space saving, which is especially important when used on printed circuits.

The further advantages and utility of the invention will become more apparent from the accompanying drawing and description.

Sheet 1 shows the invention in a side view

The carrier cover 8 is made of a high-quality thermoplastic and is designed to be easily assembled with the help of special chambers into which the attachment electrodeO, the signal electrode 12 and the disconnect electrode 14 are inserted.

A mounting electrode 10 is inserted in the carrier cover 8, which is attached to the varistor leg with a simple attachment method. Optionally, a signal electrode 12 can be inserted into the carrier cover 8. A double-sided adhesive tape 16 may be glued to the upper portion of the carrier cover 8, which is capable of withstanding high temperatures and serves to further attach the carrier cover 8 to the body of the varistor 20.

The contact nose 22 of the disconnecting electrode 14 is attached by a low-temperature solder to the disconnecting disc spring 6, which is meandrically shaped as in Fig. 1. Thanks to this design, the disconnecting disc spring 6 can be calculated on the one hand with suitable spring properties, and on the other hand the trip spring 6 serves as a flat outer contact directly inserted and ready to be soldered into the printed circuit.

The spring material has a relatively high electrical resistance and therefore, at rated current when, for example. the thermal fuse has to be disconnected, warming up enough to loosen the low temperature solder between the disconnecting electrode 14 and the fixing electrode 10.

In the invented device, a continuous current of about 16 A can flow through the junction 18 and the fastening electrode 10, with the junction 18 acting as a conductor as well as a thermal fuse, so that the said nominal value of the current of the varistor property in terms of nonconductivity is not yet expressed.

The disconnecting spring 6 is inserted into the corresponding groove of the bearing cover 8, which is an integral part of the disconnect mechanism.

The bearing cover 8 is made of a transparent non-conductive material and is designed to enable its position to be correctly positioned and also to install the disconnecting spring 6 in the appropriate position.

Of course, the indication or signaling of overloading is also possible. failures in many ways. One way is through the transparent carrier cover 8, the position of the disconnecting spring 6 is visible. Another possibility of fault signaling is given by the disconnecting voltage at the disconnecting electrode 14 so that the respective supply circuit is protected by a circuit breaker.

Claims (6)

PATENT APPLICATIONS A universal overvoltage protection device for thermal protection of varistor elements, consisting of a support cover (8) in which a fastening electrode (IO) and a disconnect electrode (14) are mounted, characterized in that the fastening electrode (IO) and the disconnect electrode (14) ) connects a disconnecting spring (6) which is connected to the attachment electrode (IO) by a joint (18) which, at a predetermined temperature, disconnects the connection between the attachment electrode (IO) and the disconnect electrode (14). Apparatus according to claim 1, characterized in that the mounted disconnecting spring (6) is designed and shaped in such a way that the spring properties are preserved in spite of the aging of the material through structural intervention and special processing technology. Apparatus according to claim 1, characterized in that the carrier cover (8) is transparent or translucent and does not conduct electricity. Device according to claim 1, characterized in that the carrier cover (8) is so secure that the device is universally usable regardless of the different types of varistors. , Apparatus according to claim 1, characterized in that the disconnecting electrode (14) is attached to the varistor leg by pressing. Apparatus according to claim 1, characterized in that an additional signal electrode (12) is mounted in the carrier cover (8) through which, after positioning the joint (18), the disconnecting spring (6) establishes a circuit.