Abstract: The present disclosure relates to a motor, in particular a compact, lightweight and high torque motor. The rotor comprises a Halbach array magnet structure in which the projected magnetic field is directed toward the rotation axis of the motor and the stator comprises a plurality of poles within the Halbach array. The individual magnets making up the Halbach array have a thickness in the radial direction, with respect to the rotation axis, which is determined to be the minimum thickness required to stop demagnetisation of the magnets when the maximum current to generate peak torque output of the motor is driven through the stator at the maximum expected temperature at which the motor will be used.