Abstract
A decline in properties of a ferrite magnet motor was studied in the case of a motor whose armature rotation was constricted at low temperature. The decline increased as the coercive force iHc of the field magnet decreased. This phenomenon corresponds to the decrease in the magnetic flux density caused by changes in the demagnetizing curve at low temperature and in the permeance coeffcient of the demagnetizing field under armature locking. The measured results for the starting torque corresponded closely calculations based on the magnetic properties of the field magnets. When the ferrite magnet motor is used at low temperature, the choice of magnet is very important.
