All Patriot Series Hoist use 3 phase motors. The difference between a standard Patriot (3-phase input power) and a Patriot "S" (1-phase input power) is in the device used to control the motor inside the control box. The Patriot "S" has a device that takes in single phase power outputs three phase power to the motor. If you are in doubt as to the unit you have received, check the serial number tag located above the motor fan inside the chassis of the hoist or count the prongs on the power cord. 3 prongs equals single phase, 4 prongs equals three phase.