Abstract :
IN THE very early days of the development of a-c transformers, various methods were tried to produce cores which would have the necessary characteristics of low loss, low magnetizing current, and suitable mechanical arrangements. It was very soon found that the most practical form of raw material was thin iron or iron-alloy sheet which could be obtained with relatively low hysteresis loss, and could be cut and assembled so as to give relatively low eddy-current loss and magnetizing current.
