Preparation of Copper Electrical Engineering Alloy Strip with High Service Properties

Abstract

Output is organized for industrial batches of electrical engineering strip with improved service properties, i.e., copper bus bars of rectangular section (σ u Ways of improving of obtaining good service properties for electrical engineering strip are considered, i.e., copper rectangular medium hard bus bar (simplification of finding σ u and clarification of surface quality evaluation after bend testing as criteria for copper grain size), commutator trapezoidal copper-cadmium strip (increase in hardness, reduction in strip camber, prevention of development of bulges and scratches in sections), and commutator copper-silver strip (increase in electrical conductivity, mechanical property stability). The limited number of articles makes it impossible to reflect to a complete extent production features for manufacturing all forms of semifinished product, in view of which only the main stages of the process and obtaining results are presented.Soft copper bus bars are used as conductors with high current loads and low working stresses: power supply for electrolyzer baths, distribution panels, control cabinets, etc. With increased mechanical loads, medium hard copper bus bars are used with increased strength properties compared with soft bus bars, but with sufficient ductility. In view of a lack within Russia of standard documentation for medium hard bus bars, they are produced in accordance with the main specifications of the British standard [1]: σ u ≥ 250 MPa; δ = 10-15%; absence of cracks with bending at an angle of 180°around a mandrel with a radius equal to bus bar thickness; the last requirement should indicate moderate copper grain size. However, there are difficulties in performing tests for these specifications.In order to prepare standard specimens with the aim of determining σ u and δ, it is necessary to select sections of bus bars, cut into billets, and specimen manufacture. For this, an appropriate machine inventory and tool facilities, standards, additional consumption of electrical energy, etc., are required in production areas (for example, within a central plant laboratory). Another disadvantage is the low efficiency of evaluating the surface condition for presence of cracks with bending bus bar at an angle of 180°, i.e., due to the fact that absence of visible cracks with an unaided eye does not guarantee a spec-

Determination of Stray Inductance of Low-Inductive Laminated Planar Multiport Busbars Using Vector Synthesis Method

“…The insulation material used is polyimide and its relative permittivity is 4. Hot-pressing [23] was used to build the planar busbar.…”