The Savings Predictor application is now available on Apple iTunes for iPhone (OS 3.1.2 or later) and iPod touch. This mobile application estimates energy savings when using a Variable Frequency Drive instead of conventional volume control methods.Variable frequency drives are reliable electronic devices that control three-phase electric motor speed. They are used in building automation, industrial, pumping, agriculture, irrigation, and water/wastewater applications to control the speed of fans and pumps in various systems. The payback period for installing drives is usually less than three years and can be less than one year.