Localized magnetic properties in grain-oriented electrical steel measured by needle probe method

The accuracy of a needle probe method in measuring localized magnetic properties of grain-oriented electrical steel sheets was investigated and its application studied. The measuring error for the localized flux density was determined to be less than 1.7% for a load on the needle tip lighter than 300 g when the yoke structure was symmetrical with respect to the sheet plane. The average of localized iron losses measured with the combination of a needle probe and a Hall probe was in linear relation to the overall losses in the sheet. This method revealed that the localized magnetic properties vary markedly from location to location inside the sheet, and that localized iron loss depends on the localized flux density, domain wall spacing, and yaw angle of grain orientation.