The present disclosure relates to electrical transformer assemblies including a first lamination assembly defining a passage therethrough; and a second lamination assembly configured and dimensioned for press-fit or slide-fit engagement in the passage formed in the first lamination assembly. The first lamination assembly includes a stack of laminations each defining a central opening and defining the passage of the first lamination assembly when in a stacked condition. Each lamination of the first lamination assembly defines at least one shaped recess formed in a side edge of the central opening. The second lamination assembly includes a stack of laminations each including at least one shaped tab extending from a side edge thereof, wherein each tab is configured and dimensioned for press-fit or slide-fit engagement in a respective shaped recess formed in the side edges of the passage formed in the first lamination assembly.