On the basis of the main laws of electro-magnetic circuit theory we propose general approach to creating four concepts of circuit mathematical models of electrical devices. It is shown that by the same assumptions their discrete analogues are different. Owing to this idea, the real possibility to present differential equatons of industrial electrical devices (static and electromechanic ones) and the systems formed by them in the normalized Cauchy form is shown, which is very important for the analysis of the long-term processes.

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