This paper describes iron losses segment cores made of grain-oriented (50ZG) and non-oriented (50H350) silicon steels. The segment core shape does not make the magnetic flux distribution uniform, and the induction frequency makes it difficult to calculate the core loss in both materials. In the segment core of grain-oriented silicon steel where the rolling direction is parallel to the yoke in the segment, the core loss is lower than in the segment core where the rolling direction is parallel to the teeth. It is also lower than that in a core made of non-oriented silicon steel at 1.5 T and 50 Hz.