Abstract: The invention relates to an interference suppression method and circuit for an electrical system, said electrical system comprising a main transformer (2) with a star point (12), phase leg conductors (L1, L2, L3) connected to the transformer (2), a neutral conductor (N) connected to the earth potential (3) and to the star point (12) of the transformer (2), and loads (5) connected between the phase leg conductors (L1, L2, L3) and the neutral conductor (N), said loads being connected to the neutral conductor (N) at connection points (4). In accordance with the invention a bandstop filter (1) tuned at a center frequency 3*f is connected between the star point (12) of the transformer (2) and the connection points (4) of the loads (5).

Abstract: An electronic auxiliary contact for a contactor has at least one switch element controllable to the conducting and non-conducting states for the purpose of indicating the position of the contact bridging member in the contactor, and a switch-activating element mechanically connected to the contact bridging member and capable of activating the switch element. The switch-activating element incorporates at least one activating element, and the switch-activating element makes no mechanical contact with the switch element. The system provides a reliable method of monitoring the operation of a contactor.