GB419634A - Improvements in electromagnetically-operated tuned or resonant relay or like apparatus - Google Patents

Abstract

419,634. Electromagnetic switches. COMPAGNIE POUR LA FABRICATION DES COMPTEURS ET MATERIEL D'USINES A GAZ, 12, Place des Etats-Unis, Montrouge, Seine, France. Jan. 2,1934, No. 159. Convention date, Jan. 13, 1933. [Class 38 (v).] In tuned relay arrangements responsive to exciting currents of particular frequencies, in order to prevent inadvertent operation of the tuned relay apparatus by likely disturbing frequencies such as harmonics of the line frequency on which the operating frequency or frequencies are superimposed, supplementary vibrating members tuned to such likely disturbing frequencies are provided, the free vibration of such supplementary vibrating members being effective in preventing operation of any of the members tuned to predetermined operating frequencies. The tuned operating systems may be electrically and/or mechanically tuned to the operating frequencies. On occurrence of a disturbing frequency the free vibration of the supplementary vibrating member tuned to that frequency is arranged to produce a counter electromotive force in the electromagnet or electromagnets controlling the operating tuned members so that the latter are not vibrated sufficiently to produce operation of the relay apparatus while such disturbing frequency is present. The above arrangements may be combined with filter circuits for eliminating the effects of certain other disturbing frequencies.