METHOD OF MAKING ELECTRICAL CONTACTS FROM FINE-GRAINED DENSE GRAPHITE IMPREGNATED WITH SILVER AND CADMIUM, ELECTRICAL CONTACT, ELECTROMAGNETIC RELAY Russian patent published in 2024 - IPC H01H1/21 H01H11/04 H01H49/00 

FIELD: electrical engineering.

SUBSTANCE: invention relates to a method of making electrical contacts from dense fine-grained graphite impregnated with silver, as well as to an electromagnetic relay with such contacts, and can be used in electromechanical relays of the first class for signaling, centralization and blocking devices on railway transport. Technical result is ensured by the fact that the contacts are made from fine-grained dense graphite with specific electrical resistance of not more than 16 mcOhm·m, compression strength of not less than 60 MPa, ash content of not more than 0.01% and volume porosity of 20–29%, which are impregnated with aqueous solutions of metal salts in vacuum, after which the impregnated contacts are calcined at high temperatures. Contacts are made in the form of a body of revolution limited by a side surface with a generatrix consisting of rectilinear and/or curvilinear sections, and two parallel surfaces of bases, made by disclosed method. Electromagnetic relay comprises a contact system of rear, front and throw-over contacts with contact material for front contacts made according to the proposed method. Stability of transient electric resistance of contact pair—graphite-silver or graphite-silver-cadmium material—silver contact is provided due to high degree of penetration and filling of pores of fine-grained dense graphite contact with silver or silver and cadmium compounds.

EFFECT: improving reliability and service life of electromechanical relay.

3 cl, 2 tbl, 12 ex