Effect of off-axis H-coil sensitivity on clockwise–anticlockwise differences of rotational power loss in isotropic samples
Wire wound H-coils used for rotational measurements are not completely immune to off-axis components of magnetic field strength H. As a result, such components are capable of introducing the significant difference between the rotational power loss measured in the clockwise (CW) or anticlockwise (ACW) direction of rotation. These measurement errors do not influence the average value, and they are distinctly different from the errors caused by the angular misalignment of the sensors in the field metric method. As demonstrated in this study even ideal angular positioning of the H-coils could still produce CW–ACW differences at the level of ±15% at lower flux density and ±30% close to saturation.