SELECTION OF THE POLE NUMBER OF INDUCTION MACHINES FOR VARIABLE-SPEEDAPPLICATIONS

The selection of the pole number for induction motors supplied from a constant frequency source is straightforward because the pole number i s determined solely by the synchronous speed required for the applicat ion, However, the selection of the pole number for inverter-driven ind uction motors is much more involved because the pole number is not det ermined by a single, dominating factor in these cases, In principle, a ny even number can be chosen as the pole number because the frequency can be adjusted and therefore the synchronous speed can be controlled to have any desired value, For these applications the selection of the pole number typically involves numerous factors and trade-offs, many of which are identified acid their influence on parameters and perform ance described in this paper, Some general conclusions on the selectio n of pole number are also presented.