GB522557A - Improvements in or relating to electric motors - Google Patents

Abstract

522,557. Motors. BETULANDER, G. A. Dec. 16, 1938, No. 36734. Convention date, Jan. 15. [Class 35] A motor has two stator units alternately energized and co-operating with axially spaced armature units on a common shaft, each arranged to co-operate with one of the stator magnets and provided with coplanar projections so that in predetermined armature positions a magnetic path exists through a field pole, a projection, an armature, a second projection of the same armature and the opposite field pole, both projections taking the same relative positions with regard to the poles and the projections on one armature being staggered with regard to those on the other. In the form shown in end and plan views respectively in Figs. 2 and 3, the armature 16 is in a magnetic circuit comprising the stator pole-pieces 3, 4, the upper halves of cores 1, 2 and the bridge 11 while the armature 17 having four pole pieces angularly staggered with respect to those of armature 16 is in a circuit including the pole-pieces 5, 6, lower halves of cores 1, 2 and the bridge 11 and the windings A1 A2 and B1 B2 are energized alternately. Instead of each core unit being U-shaped it may have additional limbs. The motor may be used with selectors for automatic telephones and operated by impulse current trains supplied to the magnet windings. When the motor is de-energized and the selector to be restored, the armature is turned to its initial position by a spring in a drum 23. For operation on an alternating supply, the field coils are fed through rectifiers reversely connected for the two winding groups. Alternatively, these two groups may be series connected, each group being bridged by a rectifier so that the two are alternately short-circuited. Polepieces and armature projections other than 'those shown in Fig. 2 are illustrated.