Mover motors draw only 10 watts or less. Light movers not only spread the light but the heat as well. This allows the light to skim over plants with out bleaching the upper leaves from constant direct brightness. Under a stationary light, the plant closest to the light grows the fastest because it receives the most energy. Eventually, the taller plant will shade those towards the perimeter and create a pattern of growth with a shape of a pyramid.
Light movers change the position of the light source so plants receive light from different angles.
A 400-watt HID light covers a 25 square foot area. On a 9-foot light track, the coverage is rated at 5 x 14 feet or 70 square feet, nearly 3 times the coverage area of a stationary light. The Light Rail Three, made by Gualala Robotics has the fastest and most versatile tracking system. These units carry the light on a very quiet trolley. Light Rail Threes can be shortened or lengthened, unlike the chain driven models.