Optimization of Rotor Tooth Shape of Aerospace Homopolar Alternators

In the first part of the optimization process, the width and depth of the rotor tooth are incrementally varied for two airgap radial lengths and two field excitations. In the second part the tooth shape that would yield a sinusoidal voltage is investigated. The numerical results are represented by curves for the no-load radial flux density in a 95 KVA, 120/208 v 3,400 cps alternator. The results show that the fundamental airgap flux density depends on the length of the airgap and on the rotor tooth width. It depends only slightly on the rotor tooth depth and excitation. A more sinusoidal output voltage can be obtained by flaring the tips of the rotor tooth and widening the rotor tooth.