SI22030A - Varistor with internal fuse - Google Patents

Abstract

Typical of the varistor with internal fuse is that the thermal safety device is located inside the cylinder-shaped varistor in such a way that the heating of the varistor due to major current shocks or due to other reasons is directly transmitted to the thermal protection device via the internal electrode of the cylinder-shaped varistor, so that the transferred heat from the varistor to the safety device results in a thermally-induced shutdown, which disconnects the circuit and thus protects the varistor and the complete surge arrestor module.

Description

VARISTOR WITH INTERNAL FUSE

The field of technology

The invention relates to a protective element for overvoltage protection of electronic or power devices, more specifically to the specific construction of varistors.

A technical problem

A technical problem is the design of the varistor, which will, in the case of large electric shocks, when it receives high energy, or in the degradation of its characteristics, allow the varistor to be protected by means of a fuse, which, upon detecting critical heating of the varistor, will break the circuit and thereby protect the varistor.

The prior art

Various forms of varistors and circuits are known to protect them due to overcurrent. According to Slovenian Patent No. 200200205, the Monolithic Circuit is known for symmetric protection of telecommunication systems with thermally coupled ptc element and varistor. The subject of the invention is a monolithic circuit for symmetrical protection of telecommunication systems with thermally coupled PTC element and varistor and is an integral part of the secondary protection of analog or digital line inputs of telecommunication systems. Monolithic circuit for symmetrical protection of telecommunication systems with thermally coupled PTC element and varistor according to the invention, enables the implementation of short circuit protection current and operating current protection at relatively low basic resistance of PTC element such that the elements are thermally coupled into PTCa + varistor a and PTCb monoliths + varistor b.

According to Slovenian Patent No. 200300039, varistor fuse box is a known solution for varistor fuse box, which consists of a varistor, a current and a thermal fuse, and is used in the system of protection of electrical devices against surges (lightning) and high currents. The varistor guard according to the invention has varistor electrodes mounted on the inside and outside of the insulating body, and a current protection and thermal protection enclosed with the extinguishing material is installed in the insulating body.

Slovenian patent number 200000324 Universal surge protection device refers to the field of overvoltage protection of varistor elements with universal overvoltage protection device, consisting of a carrier cover with a built-in fastening electrode and a disconnecting electrode, which disconnects the shielded springs by disconnecting the secured spring. cases of overheating injuries. This can eliminate the problems of power supply and solve the problem of protecting other devices connected to the same electrical circuit exposed to overvoltages. An additional signal electrode is installed in the carrier cover through which the universal overvoltage protection device also enables fault signaling.

The family of combined circuit breakers and surge protectors and lightning protection in a single housing known by patent number 200200248 includes parts of the classic part of a combination fuse such as a fuse switch disconnect lever, a fuse switch axis, an electromagnetic disconnect coil, a conventional solenoid circuit breaker. contact braid and parts of the disconnecting spring, in that these parts are preferably dimensionally subordinate to the additional installation of the varistor, and therefore generally somewhat narrower, further the device according to the invention further includes lightning protection for direct lightning strikes with a preferred energy self-extinguishing arrester, which generally includes earthing jacket, metal housing, external contact for faster ignition, high ignition transformer that transforms a rapidly increasing disturbance pulse into a predetermined ignition voltage at an additional internal gas arrester electrode, a small gas arrester, and an ignition varistor.

According to the patent RU2121724, there is a known solution of an overvoltage protection element having a disconnect varistor between two electrodes and a housing. The solution allows to reduce the production cost of the safety element.

Most of the security features and circuits described above consist of a large number of different elements, most often a varistor is used, but there is no simple construction of an element that also protects the varistor or the circuit breaker itself.

Description of solution to a technical problem

The essence of the varistor with the internal fuse according to the invention is that the thermal guard is located inside the cylindrical varistor. When the varistor is heated in case of large electric shocks or for various other reasons, the excess heat is transferred from the varistor to the thermal guard. Thus, the temperature is transferred from the inner electrode of the cylindrical varistor to a thermal disconnect, which interrupts the circuit, thereby protecting the varistor and the entire overvoltage protection module from burning.

Claims (3)

PATENT APPLICATION 5 L Internal fuse varistor, characterized in that the thermal fuse is located inside the cylindrical varistor by transferring the varistor directly to the thermal fuse via internal cylinder of the cylindrical varistor due to large currents or for various other reasons. The varistor on the guard is caused by a thermal disconnect that interrupts the circuit and thus protects 10 varistor and complete overvoltage protection module.