Torque Calculations of Polyphase Reluctance Machines

A rigorous solution for the flux-density distribution on the armature surface of a reluctance motor is given by dividing the composite airgap space into two regions and solving Laplace´s equation separately in them to get the potential distribution. The fundamental flux density is calculated and, hence, the direct- and quadrature-axis synchronous inductances for a polyphase reluctance machine. It is found possible to calculate the maximum torque in terms of the machine dimensions. Since the solutions are obtained for both rectangular-developed and radial diagrams, the error involved in neglecting the curvature can be determined. A numerical example is also given. The variation of reluctance power with polearc/pole-pitch ratio is calculated and found to be in close agreement with results obtained by previous authors.