| 摘要 |
Auxiliary protection circuit for three-phase systems with or without neutral. In this auxiliary circuit there participate as many relays 5 to 8 as phases R, S, T, N, which exist in the main circuit to be protected, said relays being connected to such main circuit, one to each of the phases referred to and in parallel with those elements in which the disconnection of a phase is provided for, such as for example classic fuses. Each relay 5 to 8 has a principal contact 14 which is normally maintained in the closed position, such that the contacts 14 of the various relays, connected in turn in series, normally close a short circuit 15 established between two points A and B, between which the auxiliary circuit is inserted in series in the circuit controlling the general contact of the element to be protected, specifically in series with the stop button, acting in a similar manner to this latter when any one of the phases of the main circuit fails. <IMAGE>
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