Abstract: An AC-DC power supply system for receiving a three phase mains supply and outputting a transformed DC supply. The power supply unit has a rectifier circuit (30) providing an output to a three phase inverter circuit (40) to generate a pseudo AC three phase output of higher frequency than the AC supplied to the rectifier circuit (30). A three phase transformer (60) receives the pseudo AC three phase output and transforms the output to a three phase rectifier circuit (70) to generate the output DC supply. The inverter circuit (40) provides a three leg bridge structure with each leg having a switching device one of which is used to provide a phase reference whereas the other two legs control the relative phase shift on each leg to reduce the phase shift relative to the phase reference on one leg and increase the phase shift relative to the phase reference on the other leg.

Abstract: The invention is directed to a cell for an electrolytic apparatus which comprises a pressure vessel containing a self-contained electrode unit. The electrode unit has an inlet for the supply of electrolyte and an outlet for liberated ad-mixed hydrogen and oxygen gas. The electrode unit further having plurality of spaced-apart concentric cylindrical electrodes and a pair of internal end plates provided at each end of the concentric cylinders. At least one of the internal end plates includes the electrolyte inlet and/or gas outlet. The pressure vessel comprises a cylindrical outer shell having planar transverse end plates which are connected at or adjacent to the opposed ends of the cylindrical outer shell. The pressure vessel being capable of withstanding explosions of stored liberated gas.