Three-phase distribution and electric welding and furnace loads

Abstract

The paper deals with the methods of connecting single-phase equipment to 3-phase mains. The single-phase transformer and the open-delta series-connected transformer are compared, both as regards current distribution and the voltages on the substation busbars. Mention is made of the power-factor correction of single-phase loads, from which there has been developed a method of obtaining balanced 3-phase/single-phase conversion by static means. The remainder of the paper gives full details of this phase-converting system for arc and resistance welding machines. Some actual operational results are tabulated.