GB597456A - An improved self-excited alternator - Google Patents

Abstract

597,456. Exciting dynamo - electric machines. SOC. D'APPLICATIONS ET DE FABRICATIONS INDUSTRIELLES SAFI. Aug. 20, 1945, No. 21231. Convention date, June 6, 1941. [Class 35] In a self-excited alternator, having an alternating current armature and a D.C. field exciting armature rotating on the same shaft and under the same stator poles, compounding is achieved by the use of an auxiliary brush situated so that its voltage depends on the distortion of the main flux by armature reaction. As shown for a two-pole machine, the armature 19 supplies A.C. at slip-rings and the armature 20 supplies exciting current at a commutator 8, the exciting current for the main field wingings 3<1>, 3<2> being derived from brushes 5, 6. The auxiliary brush 7 is situated near the trailing edge of one of the pole shoes where the flux is increased by armature reaction. The increased voltage between brushes 6, 7 is used to boost the field by auxiliary coils 4<1>, 42. In modifications (not shown), the auxiliary and main field coils are mounted on opposite poles, or alternatively the auxiliary coils are carried on auxiliary poles between the main poles.