By turning the bicycle wheel, the generator causes the light to turn on. By then applying 5-V AC to the generator, it becomes a motor which can turn the wheel. Because the generator was not designed for this use it takes a little encouragement to turn the wheel. The wheel must be turned by hand at the right speed (less than one rev. per second) in the clockwise direction in order to get the motor action started. With a little practice this is not hard to do.