Дослідження електричної ерозії поверхонь різних контактних пар низьковольтних комутаційних апаратів

Abstract

Research electric erosion contact surfaces of different pairs of low-voltage switching devices

А. Mrachkovskyi

The study of the physical processes occurring in the working surfaces of electrical contacts in the operation, creates real preconditions for future combat erosive wear, welding and burning of contacts.

One of the most common electric materials are silver-nickel CH - 30 (Ag - 70%, Ni - 30%) pseudoalloys characterized by universal application.
This material successfully combined the physical properties of the contacts is virtually no interaction of ingredients in both solid and liquid state in a wide range of temperatures and concentrations. The small mutual solubility component at molding products (800 - 1000 C) decreases with decreasing temperature is falling and particles of nickel and silver from their mutual solution, significantly strengthens and grinds grain material.

Shredding corn helps curb the crystallization process in the manufacture of a contact material, and when switching of electric current. In the grain size to erosive wear significantly affect the distribution phase components.
The purpose of research - analysis of the physical processes at work surfaces switching devices.
Materials and methods of research. Electric materials based on silver, containing 30% nickel, obtained by rolling sintered billets.This material was oriented structure: nickel particles stretched parallel to the rolling direction, providing anizotropnist physical characteristics. Samples were tested for erosive wear at a constant current of 10 A, voltage 13 V, 1 N contact pressure, ohmic load range, the total number of cycles of switching 50 • 10 3. For comparison, in such circumstances, proved contacts with pure silver. The structure of the surface contact materials studied by electron microscope JEM - 6 for the two-step method of plastic - coal replicas, pre-shaded chrome.

Research results. The dependence of erosive wear contact materials on the number and size of dial-up positives current 10 pairs for the contact made with the same names and dissimilar materials in the table. Contact experienced pair of pure silver, silver - nickel pseudoalloys and diverse pairs silver ÷ silver - nickel pseudoalloys in which materials were alternately anode and cathode.
These results shows that all material is transferred from the cathode to the anode. With the increase of a Switching current number of positives and erosive wear of contact pairs increases.

Conclusions

1. Studied erosion resistance contacts based on silver in homogeneous and heterogeneous contact pairs when switching DC voltage 10 and 13 V.
2. Established that the durability of disparate contact pairs (anode - Ag, cathode - CH - 30) 2.5 ... 3 times higher than silver and 1.5 times higher than silver - nickel alloy.
3. The working surface of the cathode made of fine pseudoalloys CH - 30 wear during switching more evenly compared to silver.