The core is build up firm interleaved low loss cold rolled, gain oriented silicon steel laminations. Individual stamping are coated on both sides with an insulating material, which is both oil & temperature resistant. The core limbs are securely bound with heavy-duty webbed cotton tapes & the yokes are family clamped between steel channels, all cores have mitered joints. Top & Bottom clamps are secured to each other by means of tie rods, which serve the dual purpose of securing the windings in place & of transferring the load from the bottom to the top clamps when the core & windings are lifted. This prevents tensile stresses being set up in the core legs, which could adversely affect the iron losses.