Examples are fans and pumps. If the speed or rpm’s of a pump or fan can be reduced to less than full load requirements, for every unit of speed reduction, the energy is reduced by the power of 3. As an example if a fan can be operated at 80% of its capacity, the energy saved can be 50%. Should a fan or pump be capable of running at 50% speed, the energy consumed can be reduced to 20%. In many processes constant speed motors turning fans or pumps moving fluids such as air and water are designed to continually operate at maximum capacity and maximum capacity is only needed part time, if ever.