GB729764A - Improvements in or relating to magnetic devices - Google Patents

Abstract

729,764. Oscillating machines. NATIONAL RESEARCH DEVELOPMENT CORPORATION. July 22, 1953 [July 25, 1952; Nov. 7, 1952], Nos. 18852/62 and 28163/52. Class 35. A magnetic oscillatory device, e.g. for gyroscopic instruments, comprises a soft iron armature having a central stem 11 with two arcuate polepieces 13 and at least one winding 14 surrounding the stem 11, and a permanent magnet comprising a base portion 15 having two arcuate polepieces 16 of opposite polarity surrounding or within the armature pole-pieces 13, there being relative angular movement between the armature and the permanent magnet. The two pole-pieces 16 are separated from each other by two air gaps 17 so that the lines of force from the permanent magnet traversing the winding 14 will depend on the shunting action of the pole-pieces 13, according to the relative position of the latter with respect to the air gaps 17. While Figs. 1, 2 show the pole-pieces 16 on the outside of the pole-pieces 13, the device can be modified whereby the armature stem 11 extends (without touching) through the magnet 15 so that the pole-pieces 13 extend over the outer instead of the inner faces of the pole-pieces 16. In a further modification, two devices as those described above may be combined in one apparatus with two coaxial armatures mounted for rotation as one at opposite sides of a common magnet or a pair of magnets. The magnetic oscillatory device can be used either as a gyroscope torque motor or as generator with a gyroscope to give signals corresponding to the movement of the gyroscope. In some cases the permanent magnet may be replaced by an electromagnet.