GB431137A - Improvements in and relating to electro-magnetic interrupters - Google Patents

Abstract

431,137. Electromagnetic interrupters. MALLORY & CO., Inc., P. R., 3029, East Washington Street, Indianapolis, Indiana, U.S.A. Sept. 26, 1933, No. 26465. Convention date, Sept. 27, 1932. [Class 38 (v)] An electromagnetic interrupter unit which may be employed in the circuit of a potential changer comprises an electromagnetic interrupter surrounded by a sound isolating casing and an outer casing of metallic material of good electrical conductivity and high magnetic permeability, means being provided for grounding the outer casing. As shown in Fig. 5, the interrupter casing comprises an outer container 161 of material such as pure iron which is lined with co-operating members 158, 159 of thick sponge rubber in order to form an inner sound isolating enclosure for the electromagnetic interrupter contained therein. The interrupter mechanism is secured at its upper and lower ends to bearing metal spiders 160 of relatively large inertia bearing on the rubber linings 158, 159 which, together with the fairly massive construction of interrupter coil and pressure, prevent the transference of vibrations from the interrupter to the outer casing and surroundings. The interrupter leads are led to prongs 153-155 similar to those of a thermionic valve so that the interrupter in its casing forms a readilydetachable unit, one of such prongs serving to earth the outer container. The leads to these prongs are made of flexible wire. The outer earthed metal container 161, by being made of a metal having good electrical conductivity and high magnetic permeability shields surrounding objects from electromagnetic and electrostatic disturbances set up in the casing. The construction of the interrupter is shown in Fig. 1 and comprises an electromagnet 121, the core 122 of which is clamped in a slot formed in the upstanding portion 117 of the yoke 116. The vibrating blade 130 is formed of uniform section and is provided with a contact 134 an appreciable distance, about midway, from its free end. This contact 134 co-operates with a contact 138 mounted near the end of an auxiliary reed 136 having a much higher natural frequency, the movement of which toward the electromagnet is limited by an adjustable stop 144. The air gap between the vibrating blade 130 and the end 123 of the fixed core is varied by inserting shims 129 between the electromagnet 121 and the yoke portion 117. The interrupter may be used in the high-tension supply system to a radio receiver of the type described in Specification 429,671. Condensers across the contact points, electromagnet and the whole apparatus may, in a modified form, be combined to replace one of the spiders 160 and thus form an inertia means for absorbing mechanical vibrations.