Projektovanje i optimizacija električnih kontakata i termičkih prekidača

Abstract

This Dissertation deals with the design and optimization of two kinds of metal based switching devices: i) riveted electrical contacts which are studied in the first part, and ii) S-type thermal cutoffs which are considered in the second part. Theoretical basis of electric contacts' design given in Chapter 1 is employed for contact material selection, proper set of contacts' geometry and dimension values and minimal contact force determination. Contacts of solid and clad types with rounded head are considered within two supporting structures. 3-D simulation of mechanical, electrical and thermal characteristics of selected contacts is steady state regime is performed and obtained results are presented in Chapter 2. Simulations are carried out in coupled domains by direct method. Special emphasis is given on dependencies of operating temperature and maximum equivalent stress in contacts under various working conditions. On the basis of the obtained results, optimization of riveted electric contacts is realized by appropriate selection of contact material, determination of geometry and dimensions of contacts and definition of rated current values. Optimization was conducted by functional, economic, ecological and reliability points of view. Possibilities of mounting the contacts in specific switching devices with predefined rated currents, as well as number of switching cycles before the failure are ore outlined. Analyzed dependencies and optimization results are described in detail in Chapter 3.