GB387792A - Improvements in or relating to switches for controlling alternating current circuits - Google Patents

Abstract

387,792. Electromagnetic switches. IGRANIC ELECTRIC CO., Ltd., 147, Queen Victoria Street, London, and WRIGHT, S. R., 113, London Road, Bedford. Nov. 28, 1931, No. 33018. [Class 38 (v).] Mechanical switches with contacts reinforced electromagnetically; arc-rupturing devices; contacts.-A fixed contact 1 on an extension of the core 9 of a series holding coil 8 co-operates with a movable contact 2 and intermediate contact 3, mounted on leaf springs 4, 5. When the magnetic or other operating force is removed from the contact 2, the coil 8 maintains the contacts 2, 3 in attracted position until the zero of the cycle, when a break occurs at 6 and subsequently another occurs at 7. The contacts may be of copper, silver, or alloy, and the contact 2 is secured by means of an iron screw 10. The main operating coil may also be wound on the core 9. In a 3-phase application, Fig. 3, a closing coil 21 attracts its armature 20 which is insulatedly pivoted at 18 and connected by springs 19 to each of three levers 17 also pivoted at 18. The levers 17 thereupon rotate levers 13 about their pivots 14 so that contacts 12 are caused to engage fixed contacts 11. In opening due to de-energizing of the magnet 21, the holding coil 16 releases the lever 13 associated with one phase at the zero of the cycle, leaving the other levers 13 closed on to a single-phase circuit, which levers are subsequently released together by their coils 16, creating a double break. The contacts 12 may be carried by iron carriers 23 and may have intermediate contacts as in Fig. 1. The Provisional Specification refers to the hold-on coil as serving also as a blow-out coil.