Abstract: The permanent magnet rotor of a brushless d.c. motor is provided with regions of reduced magnetization in the mid-portion of the poles and spaced from the pole gaps, these regions being offset towards the extremity of the rotor where a portion of the rotor extending beyond the air gap of the motor serves to control a Hall I C sensor for control of the current in the stator windings. The regions of reduced magnetization do not interfere with the rapid switching of the Hall I C, but in a cylindrical air gap motor reduce the axial thrust on the rotor resulting from the asymmetric extension of the rotor out of the air gap which is provided for commutation control. Since this thrust is of a pulsating character, its reduction is important and permits simpler bearings to be used for the rotor shaft. Apart from reducing the axial thrust, the pattern of magnetization above described reduces non-uniformity in the current flow in the windings and therefore also variation in torque during a revolution of the motor.