Emmedi Welding & Annealing Division of Saet S.p.A.
New Solid State Welder
On the occasion of Tube Dusseldorf 2008 EMMEDI, the Welding & Annealing Division of SAET GROUP, will show the new solid state welder, 250kW output power, based on a MOSFET inverter able to work up to 450kHz. The new welder is composed by the following units: transformer, power supply, welding head, cooling system and control desk. The power supply is a three-phase full bridge thyristor rectifier. Proper filters are inserted in order to reduce the harmonic components that could effect the welding process. A system control board communicating with the Inverter through optical fibers is provided on this unit. The inverter is a current fed type, composed by a proper number of modules (rated power 25kW each) connected in parallel: output oscillating circuit is directly connected to the inverter. Proper protections (hardware and software) have been implemented both on the single module and on the whole system to limit component failures. The modular structure and a complete diagnosis system allows a quick and easy maintenance in order to reduce production stops. A special digital control system has been developed for an optimum phase locking (and then for an efficiency increasing) with the possibility to follow the change of frequency due to load variation, at any working condition. For a quick and cheap solution in case of technical problems and therefore for a reduction of possible interventions in site, SAET GROUP offers a special service in remote mode called TELESERVICE which allows our technicians to operate from our Premises directly into the Welding Unit installed at the customer plant.