Resistance change of contact groups of low-voltage electrical apparatus: Determining the laws

The main Russian and foreign manufacturers of low-voltage electrical devices - circuit breakers, fuses, magnetic starters, knife switches packet are presented. data experiments for determining the resistance values contact groups switching equipment considered. design features that determine value resistances power circuits investigated a classification is proposed depending on elements devices. A methodological approach an algorithm detailed analysis given. Experimental schemes study proposed. conducted as function flowing currents shown. During it revealed contacts changes value, type time exposure to current within +/-5 %. laws characterize ratio structural components (contact systems, thermal relay, coil maximum relay) have been defined. Empirical expressions graphical dependences systems obtained magnitude rated equipment. minimum sample size number during experimental research determined, sufficient calculate mathematical expectation connections with given accuracy. As result studies, joints can increase operation by 2-2.5 times. established change in be used predict technical state installations intrashop networks, clarify amount electricity losses shop networks up 1 kV, also additional regulation maintenance scheduled preventive maintenance.