Comparison of rotational single sheet testers for evaluating 2-D magnetic properties of electrical steel sheet

Evaluating magnetic properties accurately under various flux conditions is necessary to reduce iron losses in designing motors and transformers. Particularly, two-dimensional (2-D) magnetic property is one of the most important factors for highly efficient electrical machines. In order to evaluate 2-D magnetic properties of electrical steel sheets, several types of 2-D single sheet testers (2-D SSTs) have been proposed. The structure of magnetizing yoke and coils in a 2-D SST is more complex than an SST for measuring one-dimensional (1-D) magnetic properties of electrical steel sheets (1-D SST). Therefore, leakage inductance of a 2-D SST is generally much larger than that of a 1-D SST, which results in the fact that it is very difficult to measure magnetic properties up to high flux density region with a 2-D SST. In this paper, a round rotational 2-D SST (RRSST) is developed based on motor stator core. The RRSST is compared with the 2-D SST using a square specimen (SRSST) from the standpoint of 2-D magnetic measurement in high flux density region under rotational and alternating flux conditions.