Electrical machines with higher efficiency through combined star-delta windings

Combined windings have higher fundamental winding factors and produce smaller harmonic contents. Therefore, the efficiency can be increased without any additional active mass. This paper presents specifics of the combined windings. Special topics are the higher efficiency in comparison to machines with the same size and classical windings, design and calculation of combined windings, winding technique and experimental results of a 30 kW standard asynchronous motor.