The Effects of Slotting on the Flux Distribution in Saturated High-Speed Homopolar Inductor Alternators

The effect of slotting not considered in previous papers, is analyzed by taking into account the actual slots of the stator. The equations and methods of Ref.l and 2 are used with some modifications. The boundary conditions at no-load on the lines of symmetry have been replaced by the value of the potentials and thus, improved convergence has been achieved. The flow chart of the main program for an IBM 7090 and the flow chart of an IBM 1620 program for calculating the potentials on the lines of symmetry are given. In a simplified solution, the actual slotted region is replaced by a smooth airgap and an equivalent " synthetic" region of homogeneous iron. The methods are used to calculate the no-load flux distribution and no-load voltage of a 95 KVA, three-phase 115/200 v, 3,400 cps., high-speed inductor alternator. The fundamentals and higher harmonics of the different solutions are compared. Calculated no-load voltages compare with test results very closely.