The York S1-6109899 3HP Controller Programmed VFD 460V/3PH is a variable frequency drive (VFD) designed to regulate the speed of compatible HVAC motors. It works by adjusting the frequency and voltage supplied to a three-phase motor, allowing precise control of motor speed according to system demand. This component is commonly used in compatible York HVAC equipment, including air hand... https://www.partshnc.com/s1-6109899-york-460v3ph-3hp-programmed-vfd