Shouichi Kawamata

Motor performance and magnetic properties of rotors with directly injected bonded magnets in laminated Fe-Si sheets

Directly injected bonded magnets in rotors have attracted attention because the injection process has various advantages compared to the application of sintered magnets. Anisotropic Nd2Fe14B, Sm2Fe17N3, and Sm2Co17 compounds were directly injected in rotors with laminated Fe-Si sheets. All bonded magnets had easy magnetization direction in the radial direction. The value of the coercive force for injected Nd2Fe14B was 17.9kOe at 298K and was smaller than that for Sm2Co17 at 398K. Demagnetization was found for all the bonded magnets in a magnetic field of −1kOe at 398K. The induced voltage wave forms for the three rotors showed sine waves. The value of induced voltage for Nd2Fe14B bonded magnet rotor reduced with increasing temperature by −0.16%∕K, which is in agreement with the temperature coefficient of Br.