REGIMUL DE COMUTA?IE AL DISPOZITIVELOR ?N VIDCU SARCINI INDUCTIVE

摘要

At the interruption of the current in the inductive circuits, in the void transformers orrnelectrical motors, in the starting of an electrical motors, the vacuum switching devices can berngenerated over-voltages. Thanks to the special properties of vacuum these over-voltages may be arndifferent source given the over-voltages generated in the same conditions by a switching devicernwhich used an other arc-extinguishing medium (air, SF6, oil, a.o.). The present work propose newrnmethods of analysis of the phenomens generated by over-voltages appearance and new methods ofrnprotection which provide the limitation or quenching of the over-voltages.rnWe are study a lot of issues of phenomens which are generated by the over-voltages: an ideal currentrnswitching for an inductive load, the breaking current for small inductive load, multiple startingrnoperations and multiple ignitions.rnWe are present the charecteristics of the apmplification of over-votages and the characteristics of therncomutation over-voltages in due time of the multipleignition.rnThe methods of limitation or quenching over-voltages are presented:the utilisation of the softrnmaterials - AgWC, CuBi – with a small breaking current,the utilisation of a syncrounousrnbreaking,and the utilisation of the devices for limitation of the over-voltages.