Physico-chemical analyses of the ignition behavior of intrinsically safe AC circuits

The use of explosion-protected electrical equipment of the type of protecti on ,,intrinsic safety" requires that safety measures or an appropriate desi gn ensures that the equipment cannot cause an ignition of an explosive gas mixture, neither under normal conditions nor in the case of a defect. When intrinsically safe equipment is fed with AC current, it turns out that, in the case of single successive half-waves which, separately, are unable to c ause an ignition, an accumulation of the individual energy values may take place which may lead to an ignition of the gas mixture. These accumulations are investigated with the aid of numerical simulations, the aim being the identification of the dominating physical and chemical processes.