Comparison of Halbach magnetized brushless motors equipped with air-cored and iron-cored rotors.

The performance of Halbach magnetized brushless motors equipped with air-cored and iron-cored rotors is investigated theoretically and experimentally. It is shown that an optimal combination of magnet thickness and pole number exists for maximum air-gap flux density. By employing a rotor back iron, the air-gap field and hence the output torque can be enhanced significantly if the ratio of the radial thickness of the magnet to the pole pitch is small. [ABSTRACT FROM AUTHOR]