GB289804A - Improvements in or relating to magnet systems for converting electrical into acoustic oscillations and vice versa - Google Patents

Abstract

289,804. Naamlooze Vennootschap philips' Gloeilampenfabrieken. May 2, 1927, [Convention date]. Magnetic instruments.-A balanced ferromagnetic system for converting electrical into acoustic oscillations or vice versa has an air gap or paramagnetic material, as distinct from ferromagnetic material, provided in the path of the permanent flux to cause a high reluctance therefor. With such an arrangement weak springs are sufficient to return the armature to its normal position. Fig. 1 shows a balanced armature system in which the armature 14 is located between pole pieces 12, 13 separated from a permanent magnet 11 by air gaps 17. The armature is pivoted at 15 and surrounded by immovably arranged speech windings 18. In this arrangement the total amount of the magnetic fluxes produced in the poles of like nature is substantially constant, whilst the alternating flux produced by the current in the coil meets with a normal reluctance. The Specification as open to inspection under Sect. 91 (3) (a) comprises also a construction, Fig. 1, (Cancelled) in which a permanent magnet 1 carrying the speech windings 8 is provided with pole pieces 2, 3 between which is an armature 4 carried by a weak spring 5 clamped at 6. Small air gaps 7 are provided between each pole piece and the magnet. A wide air gap is preferably provided between the armature and pole pieces. This subject-matter does not appear in the Specification as accepted.