BigPatents India

The present invention relates to a multi-stage down chopper for arc welding by creating current flow between I an electrode and a workpiece, said chopper including a D.C. input source, a first switching stage, with a first switch device and a first choke, said first stage selectively connects said D.C. input source across said electrode and workpiece at a controlled duty cycle and switching rate, a second switching stage, with a second switch device and a second choke, said second stage selectively connects said D.C. input source across said electrode and workpiece at said controlled duty cycle and switching rate, and a pulse width modulator for controlling said duty cycle and switching rate in accordance with a control signal, the improvement comprising a magnetically permeable core and means for transformer coupling said first and second choke by winding said first and second chokes onto said core.