Patent ID: 6498736
Filing Date: 2002-12-24
Classification: H01F

Abstract:
A system for reducing harmonics in a circuit, the circuit being powered by a main three phase power source having a main three phase voltage set, each main phase voltage having a main voltage amplitude and a main voltage phase, the system comprising:main rectifier means having a main rectifier output; auxiliary rectifier means connected directly to the main rectifier output of the main rectifier means; and an autotransformer connected to the main rectifier means and the auxiliary rectifier means, the autotransformer having a delta configuration and adapted to generate a set of auxiliary voltages isolated from the main three phase voltage set, each auxiliary voltage having an auxiliary voltage amplitude and phase, the auxiliary voltage amplitude ranging between 0.70 and 0.75 times the main voltage amplitude, and the auxiliary voltage phase ranging between 55 and 65 degrees out of phase with the main voltage phase, whereby twelve pulse rectification is achieved.