Reducing voltage regulation in toroidal permanent-magnet generators by stator saturation

The output voltage of a permanent-magnet generator reduces on load because armature reaction mmf leads to reduced flux. The paper describes a simple solution which can greatly reduce the regulation and which is particularly applicable to 'Torus' machines. If a stator core of reduced thickness is used, heavy saturation takes place on no-load so that, when load current flows, the armature reaction mmf simply reduces the degree of saturation. The stator coils then link the same rotating flux whether current is drawn or not and the terminal voltage is not greatly affected by armature reaction.