GB817110A - Improvements in or relating to magnetic damping devices - Google Patents

Abstract

817,110. Magnetic brakes. WESTING- HOUSE ELECTRIC INTERNATIONAL CO. Nov. 16, 1956 [Nov. 18, 1955], No. 35098/56. Class 35. [Also in Group XXXVI] In a magnetic damping assembly 143, such as for a multi-element induction instrument, e.g. a three-wire circuit watthour meter, comprising a permanent magnet 147 having two coplanar magnetically opposed pole faces 151, 152 which with two spaced polepieces 158, 159 forming an armature 156 define two air gaps 160, 161 for receiving an electro-conductive disc 39, the magnitude of the magnet flux traversing the air gaps is variable by adjustment of a magnetic shunt 165 which engages one surface of a non-magnetic plate 162 on the other surface of which is carried the armature 156. A non- magnetic portion 157, e.g. an air gap spaces the polepieces 158, 159, and the carrying plate 162 is secured to a supporting frame 85 by stated extensions 163. The shunt 165 is adjusted by a screw member 173 which is biased by a compression spring 183 and engages clearance and screw-threaded opening 169, 170 in the shunt terminal portions 167, 168; the shunt central portion 166 is biased to engage the plate 162 by a bronze spring member 184 compressed between a guide slot 200 in a frame projection 115 and shunt terminal portion extensions 167a, 168a, and the spring member terminal part 188 is proportioned to engage the disc lower bearing assembly 123 before the screw member 173 reaches the shunt screw-threaded terminal portion 168 to prevent accidental disengagement of the shunt. Preferably there are two such magnet assemblies at diametrically opposed areas of the disc 39. Specifications 812,903 and 812,904, [both in Group XXXVI], are referred to.