Characteristics of a Brushless and Exciterless, DC Exciting System Three-Phase Synchronous Generator.

It is desired from viewpoints of maintenances and constructions to make three-phase synchronous generators brushless and exciterless type.To meet this requirement, one of the authors devised a brushless and exciterless synchronous generators in which exciting currents flow simultaneously with load currents in armature windings.Thus, generators can be used both as the generators themselves and as the exciters.A generator system has already been reported by one of the authors.In this generator, the DC stator exciting current flows between the middle points per phase of the double-star armature winding through the rectifiers.However, the winding connection between the armature winding and the rectifiers are complicated.The three-sets of the rectifiers are needed by the stator excitation.The authors present a generator system by which the electric connection of between the stator armature winding and the rectifier can be simplified, and the number of the rectifiers can be reduced.In this system, the stator is provided with a double-star armature winding having two neutral points.In this paper, first, a circuit constitution and the principle for the brushless and exciterless three-phase synchronous generator are described, and secondary, the characteristics are made clear by being based on the characteristic analysis.Further, the results of the experiments for the generator carried on the test machine of 2.0 kW are shown.