The present invention relates to a magnetic propulsion motor comprising a magnetic drive assembly comprising a drive magnet, a rotating hub, and a motion magnet attached to the rotating hub to rotate the motion magnet proximate to the magnetic drive assembly. The protection circuit is suitable for being disposed on a light on tester that may output a test voltage to a display module. A mask level sensor can be used to detect the level of the mask and the actuators operate to keep the mask at a constant level. In the closed configuration, a fastener is placed at a portion of the lower edge of the front flap, i. If it lies outside the permitted range then an emergency stop is initiated.