PROCESS OF MANUFACTURE OF ELECTROMAGNETIC SWITCHING DEVICE Russian patent published in 2001 - IPC

FIELD: electrical engineering, low-voltage equipment, design of contactors and starters. SUBSTANCE: process of manufacture of electromagnetic switching device includes manufacture of frame, core with pull-in coil, armature, casing, shock absorbers, units of contact cross-pieces, mobile bridge contact units in the form of contact bridges with contact straps containing silver welded to them, block with immobile contact units with contact straps containing silver and return springs, assembly of device, its painting, marking, test and packing. Specific feature of invention is that contact straps containing silver of at least part of mobile bridge units are fabricated with variable cross-section within limits of quarter of their height as minimum on side of contact surface that diminishes towards one face of strap. Strap and contact bridge are installed in steel frame of variable thickness rectangular in plan while straps containing silver are welded to contact bridges. Contact bridge is put into longitudinal groove of variable depth formed in frame whose depth is deeper on one end of frame and strap subject to welding is placed in cut-out whose configuration and dimensions correspond to configuration and dimensions of strap in bottom part of groove at the other end of frame. After this frame with contact bridge and strap installed in it is led under welding machine and strap is welded to contact bridge. Then contact bridge with welded strap is removed from frame and inserted again into frame with another end placing welded strap over deeper section of groove. Second strap containing silver is put into cut-out and welded. After this manufactured mobile contact bridge is removed from frame. EFFECT: possibility of manufacture of electromagnetic switching device with high switching wear resistance, reliable in process of long-term operation and requiring no complex operations for its assembly, considerably accelerated drift of arc and prolonged service life of both contact units and device as whole. 18 cl, 19 dwg