GB369903A - Improvements in or relating to electrical switches - Google Patents

Abstract

369,903. Electromagnetic switches. PAYNE, M., 50, Hook Road, Surbiton, Surrey. Nov. 29, 1930, No. 36009. [Class 38 (v).] In electromagneticallyoperated switches in which a spring or gravity-controlled contactcarrying armature and the co-operating fixed contact are enclosed within a sealed vessel containing oil or an inert gas, the external operating electromagnet has a hollow cylindrical iron core which surrounds the tubular portion of the vessel in which the iron plunger armature is located and is formed with annular polepieces so that when the armature is attracted to bring the contacts into engagement, the magnetic circuit of the external magnetic shell is completed by the internal iron plunger. As shown in Fig. 1, the glass casing c is surrounded by an electromagnet h and contains a magnetic plunger e suspended by a spring f from an upper terminal k which passes through a rubber lining g tightly closing the upper end of the casing, the core e having an extension i carrying a resilient movable contact a. The fixed contact b attached to a terminal n is similarly secured to a rubber lining j at the lower end of the casing. The casing is filled with oil or with an inert gas and on energization of the electromagnet the core e is drawn down to bring the contacts into engagement, the upper portion d of the casing being tubular to guide the core in its movements. In a modification, Fig. 3 (not shown), the casing may be of cylindrical formation. The operating electromagnet h is surrounded by a cylindrical magnetic shell h<1> formed with annular polepieces so that the armature e when attracted completes the magnetic circuit between these polepieces. In a further modification, Fig. 2, the movable core e is lifted against gravity on energization of the electromagnet current being led to the movable contact a through a flexible connection l attached to a lateral terminal m.