GB419035A - Improvements in and relating to electromagnetic relays - Google Patents

Abstract

419,035. Electromagnetic switches. GENERAL RAILWAY SIGNAL CO., Rochester, New York, U.S.A.-(Assignees of Field, O. S. ; 473, Seneca Parkway, Rochester, New York, U.S.A.) May 1, 1934, No. 13158. Convention date, May 24, 1933. [Class 38 (v).] An electromagnetically-operated tractive relay of the polar-neutral type has its neutral armature or armatures acted upon by a magnet system which is only rendered effective to cause the neutral armature or armatures to move from the retracted to the attracted position when the polar armature occupies that one of its two operated positions which corresponds to the polarity with which the relay is energized. As shown the relay comprises parallel cores 3, 4, 5 united by a yoke 6 at their upper ends. The central core 4 is a permanent magnet or permanently energized electromagnet for magnetizing a polarized armature 13 pivoted at 14 and having its upper end movable between enlarged polepieces 7, 8 of the cores 3, 5 which carry sets of windings 9, 10 and 11, 12. The circuit of the windings 9, 10 is completed from a battery B through reversing contacts 16, 17 operated in conjunction with a railway switch TS by a switch machine SM and the polar armature is arranged to be swung to the right or left in accordance with the direction of current through these windings. Contacts 18, 19 control the direction of current from a battery B<2> to the coils 11, 12 and the normal directions of the currents in the two sets of coils are such as to assist each other so that their combined effects are arranged to be just sufficient to attract the non-polarized or neutral armature 18. If, however, the polarized armature, which is arranged to be operable on reversal of the current in coils 9, 10 by the difference in flux produced by these coils and the coils 9, 10, fail to operate when the current reverses on changing over of the switch TS, the reduced flux is not sufficient to attract the armature 18 and the controlled circuits, which may include series connected contacts of both armatures, are not closed. As soon as the polarized armature does respond, however, the reversal of current in coils 11, 12 enables the armature 15 to be attracted and normal working is resumed. Thus the neutral armature is released at each change-over of the contacts 16, 17 and is only attracted again if the polarized armature has correctly responded to the changeover. In a modified arrangement, the current in the auxiliary set of windings is controlled by oppositely connected rectifiers which are switched in alternately by the polarized armature. Specification 318,916, [Class 38 (v)], is referred to.