RU108210U1 - SURFACE INSERT FOR SURFACE MOUNTING - Google Patents

Abstract

 A fusible insert for surface mounting, containing a ceramic body with contacts and a soldered fusible element made of silver wire, characterized in that the contacts are made by applying an aluminum-copper-silver composition along the faces and ends of a rectangular ceramic tube.

Description

The fusible insert belongs to the field of electrical engineering and can be used to interrupt the electrical circuit in equipment with a supply voltage of 150 V at specified overload currents up to 50 A in order to protect the equipment from destruction and failure.

There are standard rows of fuse-links for rated currents up to 10A and more [1-2].

A high-voltage current chopper is known, comprising a housing of insulating material with a channel, inside of which there is a conductor connected to current leads, in which the ratio of the channel cross-sectional area to the conductor cross-sectional area is from 6.2 to increase the reliability of the interrupter and increase speed by eliminating arcing up to 32 [3]. The disadvantage of this design is the lack of mounting options on the housing of the current leads, providing minimum overall dimensions and protection of the circuit breaker from destruction by excessive pressure during combustion of the conductor.

Known designs of fusible inserts for currents from 32 mA to 10A with a length of not more than 20 mm and a case diameter of not more than 3 mm with a case made of glass or ceramic [4-6]. The fastening of the contacts (current leads) to the housing in such inserts is carried out either by glue or a tight connection. The disadvantage of such structures is the destruction of the details of the inserts (housings, contacts) at overload currents above 50A and voltages greater than 100 V.

The closest in technical essence is the design of fusible inserts for currents from 1 to 16 A, with a length of not more than 20 mm and a case diameter of not more than 3 mm with a ceramic case and stamped copper contacts soldered to the parts of the ceramic tube metallized with paste [7].

The disadvantages of this design include the complexity of the mechanization of applying and burning paste on a ceramic tube, the need to manufacture dies and contacts from copper tape, their galvanic coating and soldering with solder to the metallized body of the insert by melting.

The purpose of this technical solution is to exclude the operations of manufacturing stamped contacts and soldering them on the body of the fusible inserts. This goal is achieved by the manufacture of aluminum-copper-silver contacts of fusible inserts by gas-dynamic spraying on the edges and ends of rectangular tubes through stencils, which ensures the use of group methods and process automation. At the same time, this leads to a decrease in thermal resistance between the body of the fusible inserts and the printed circuit board, provides surface mounting of fusible inserts on the contact pads of printed circuit boards, and excludes the manufacture of printed circuit boards with metallized holes. This leads to a significant reduction in the complexity in the manufacture of fusible inserts, printed circuit boards and installation operations in the equipment.

In FIG. The proposed device is shown.

The manufacture of contacts on a tube with a rectangular profile by the method of gas-dynamic spraying of metal powders is carried out in a single cycle and sequentially along the edges and ends of the ceramic tube 1 by forming an aluminum sublayer of 50 μm, then a copper layer of 150 μm and a thin layer of silver 10-20 μm on top. Then the contacts are soldered with solder 3 (ПСР 3.0 GOST 19738-74), and the fusible element made of silver wire 4 is soldered to the contacts with solder 5 (PSR 1.5 GOST 19738-74) with simultaneous sealing of the end holes of the insert by melting.

The contacts of the fusible insert made by gas-dynamic spraying provide high strength of their connection with a ceramic tube, high-quality heat dissipation and soldering to the contact pads of the printed circuit board. When the supply voltage is applied to the insert and the overload current is passed through the fusible element, the latter melts with the formation of an arc, which is extinguished without breaking the case and contacts. The use of the proposed contacts of the insert fusible protects the ERI in the device in which the insert is used, in the event of increased voltages and overload currents, including damage from the combustion products of the fusible element.

The breaking capacity of the proposed device with a length of 7 mm with a cross section of a rectangular ceramic case of 3x3 mm and copper contacts, rated for a rated current of 1 and 5 A, was experimentally verified, and their response time was checked. Overload currents of 40 and 50 A were passed through an insert with a silver fusible element at a supply voltage of 150 V. The fusible elements of the inserts melted without external damage to the structural elements, the response time did not exceed the technical requirements [8, 9]. The design of the fusible insert has the possibility of automated manufacturing and high adaptability, low cost.

Literature:

1. GOST B 21246-75 Insert fusible. General specifications.

2. GOST 17049-71 Insert fusible for rated currents up to 10A. Dimensions.

3. A.S. USSR No. 2744141 High-voltage current chopper / S.V. Lebedev, A.I. Savatimsky, G.I. Mozharov. Publ. in the BI. No. 2 of 1981

4. Specifications 0100.480.003T UR.

5. Technical conditions of EIZHA.6685 521.001 TU.

6. Internet http: // www. siba. de.

7. Patent for utility model No. 101581, fusible insert // Parnachev V. P., Maryanov G. M. // 2002

8. Specifications. Fuse links WFP-380-16. ЕИЖА.646123.005.

9. Technical conditions. Fuse links WFP-150. ЕЖЖА.646123.006.

Claims (1)

A fusible insert for surface mounting, containing a ceramic body with contacts and a soldered fusible element made of silver wire, characterized in that the contacts are made by applying an aluminum-copper-silver composition along the faces and ends of a rectangular ceramic tube.