Patent No.: 8,403,112 (get PDF)

Title: Hoist system with high system power factor

Assignee: Sky Climber LLC

Abstract: A suspension work platform hoist system having reduced reactive power to produce a hoist system power factor of at least 0.95 when operating at a steady state full-load condition as the motor raises the work platform. The hoist system power factor takes into account all the power consuming devices of the suspension work platform hoist system as well as a suspended conductor system that connects the constant frequency input power source to the hoist, which is often in excess of several hundred feet. The hoist system power factor may be achieved by incorporating a reactive power reducing input power system into the suspension work platform hoist system. The reactive power reducing input power system decreases the magnitude of the reactive power of the motor producing a high hoist system power. The reactive power reducing input power system may include an AC-DC converter and a regulator system in electrical communication with a DC-AC inverter that is in electrical communication with the motor.