GB141554A - Improvements in magneto electric machines - Google Patents

Abstract

141,554. Olivetti, C. June 11, 1919. Magneto-electric machines. - Magnetos for igniting in internal-combustion engines and for other purposes are constructed to give six maxima of tension for each revolution of the armature: the maxima may occur at equal or unequal intervals from one another. Figs. 1 and 2 illustrate a construction in which maxima occur at intervals of 30, 60, 90, 30, 60, 90 degrees, as shown by the depressions 34, Fig. 14, of the interrupter cam 32. The field-magnet comprises one or more permanent magnets 12 fitted with pole-pieces 3, 3<1>, and between the rotating armature core 1 and the polepieces there are arranged four segments 4, 4<1>. 5, 5<1> of magnetic material. These segments are firmly held by two non-magnetic plates 6, 7 which may be adjusted for timing purposes through a limited angle around the armature shaft; two of the segments 4, 4<1> rest against the pole-pieces 3, 3' while the other two segments are positioned in the interpolar gaps. The armature comprises a soft iron core 1, carrying primary and secondary windings 16, 17, and two arc-shaped soft-iron segments 2, 2<1>, spaced apart from the ends of the core 1; the several parts ure secured together by means of end pieces 8, 9 mounted in bearings 10, 11. The intervals separating the maxima may be altered by suitably proportioning the lengths of the segments and of the ends of the armature core. The low-tension winding 16 is connected to an interrupter having an oscillating lever 41 and carried on the plate 7. Six sparks per revolution may be obtained by using an internal cam 32 with six projections or depression 34, as shown in Fig. 14, or four sparks having a relative displacement of 90 degrees by using cams of the character shown in Figs. 17 and 19. Magnetos of the type described may be arranged to give two sparks per revolution by turning the stationary segments into the position shown in Fig. 8. The segments 4, 4' may be omitted, Fig. 7. Modifications in which sparking occurs at unequal angles may be used for the ignition in V-engines.