GB389794A - Improvements in electric measuring and power supplying apparatus - Google Patents

Abstract

389,794. Current and pressure meters ; loud-speakers. DEPAEPE, H., 78, Rue Fondary, Paris. June 16, 1931, No. 17501. Convention date, June 17, 1930. Void [Published under Sect. 91 of the Acts]. [Class 37.] In a moving iron electric measuring - instrument or loud-speaker the permanent magnet providing the directing field is provided with an additional limb 4 terminating equidistant from the magnet poles, the permanent magnet being included in a magnetic circuit energized by the actuating current so as to weaken the directing field. In the Figure the energizing winding is divided into two series connected parts 5, 6 one on each limb of the permanent magnet and wound so that the flux due to each flows upwards (or downwards) in each limb, thereby producing a pole at the end of the limb 4 and decreasing the strength of the poles 2, 3 to produce rotation of the pivoted moving core 10. In a modification the winding is all arranged on the limb 4. In the application to electric measuring-instruments the aperture of the scale, over which a pointer attached to the moving core 10 moves, is varied by adjusting the position of the pole on the limb 4 with respect to the pivot of the moving core 10 and the line joining the poles 2, 3 of the permanent magnet, the graduation of the dial depending on the shape of the core 10. As applied to loud-speakers, the moving core 10 is connected through a rod to a diffuser.