Analysis of a thrust magnetic bearing with rectangular wire winding

Active magnetic bearings generally use the coils made of enameled round wires, which have a low filling factor and waste plenty of slot space, resulting in large volume and weight of the machine. This paper introduces the rectangular wires to apply in magnetic bearings. The rectangular wires can be wound compactly without gaps and increase the wire filling factor, thereby reducing the size of the magnetic bearing stators, as well as the associated rotor part. These structural improvements are greatly beneficial to the high-speed rotating machinery in the aspects of windage losses, natural frequency, and material strength of the rotor, which are quantitatively analyzed. By utilizing the rectangular wire, a coil for a thrust magnetic bearing prototype is fabricated and tested, demonstrating the practical feasibility of the rectangular wires to apply in magnetic bearings.