Evolution of Axial-Field Electrical Machines

Abstract

This paper is a review of axial-field electrical machines, which were at the origin of the invention of electrical machines such as the famous Faraday’s disk. The different configurations of the axial-field machines are presented along with their advantageous key steady state characteristics such as high efficiency and high power to weight ratio. The differences between axial-field machines and conventional radial-field machines are discussed. The disc-type axial-field electrical machines with permanent-magnet excitation seem to be among the best designs in terms of compactness, suitable shape, robustness, and electric characteristics. Axial-field machines are expected to be used in a large number of applications in the future owing to their special features and distinct advantages compared to conventional radial-field machines.