Transformers used for the distribution and control of electrical energy consist of a primary and secondary copper wound coil carrying a magnetizing current surrounding an iron core which is used for the transferring of power from the primary to the secondary coil.

The iron core is normally made of thin gauge laminated steel either of low cost stamped laminations in the assembly form of EI's or EE's (see Figure 1) or similar laid up structures sometimes in a more costly strip wound double cut core assembly as shown in Figure 2.

Stamped laminations are usually made of .006" thick material and can go as high as .025", the cost for producing the lamination is very low, but the high cost comes from the stamping dies used to stamp the laminations and also the final assembly by the customer. While cut cores can be made of very thin magnetic steel strip (such as .001" and can go as high as .014") wound over simple low cost mandrels, heat treated, impregnated, and finally cut into two pieces as a completed set and ready for customers use.