In this third volume, we have outlinesof laminated and rolled steel electromagnetic structural evolution of new range of Transformers; tentatively called:O-Core, H-Core and Y-Core units. They could be further extrapolated as: Ring-Core and Disc-Core Transformers for greater applicability. They are envisaged to offer improved electromagnetic circuits; havingminimized reluctances, reduced core losses in almost eliminating leakage fluxes and pursue economic construction in operation. Disc Core units become amicable for introducing air-gaps ans DC field coils; in making Voltage Regulators; apart from the feasible conditions of developing lage Twin Transformer Voltage Stabilizers.