Close-ratio phase-modulated change-pole machines with improved winding balance

The windings are divided initially into short segments which are balanced by the distribution of the phase-band lengths on a first pole number. Balance for the second pole number is then achieved by interleaving at least two of these segments. The material is supported by some practical tests on both 3- and 2-phase versions of the windings; the 3-phase experimental machine is compared with a single-speed machine in the same frame, while the 2-phase machine is used as a capacitor-run fan drive and is again compared with a single-speed version.