Stator Teeth Tips Shape Influence in Permanent Magnet Synchronous Motors on a Test Bench

In order to optimize key aspects of the performance of electrical machines, all the design features need to be analyzed. The study is focused on the influence of the teeth tip geometries of Permanent Magnet Synchronous Motors. Open slots and semi-closed slots are considered, and the performances are evaluated measuring the electromotive forces induced in several search coils inserted inside the slots. This analysis is done experimentally by means of an innovative test bench where small pieces manufactured like the stator with different teeth geometries can be inserted and interchanged easily and economically, without the need to build an entire stator each time. Semi-closed slots generate bigger back-EMF amplitudes than open slots, but both generate frequency harmonics of similar amplitudes, so semi-closed slots show a better performance. This experimental test bench is also used to verify the FE electromagnetic simulation models; the correlation with measurements shows good agreement.