Study of the Counterclockwise/Clockwise (CCW/CW) Rotational Losses Measured with a Two‐dimensional Vector Magnetic Property Measurement System

Abstract

Abstract In the development of high‐efficiency actuators, high‐magnetic flux density conditions are applied to achieve higher torque, lower weight and smaller size. It is therefore very important to understand the magnetic properties under high‐magnetic flux conditions in the electrical steel sheets. However, it is very difficult to measure the two‐dimensional vector magnetic properties under high‐flux density conditions due to nonlinearity and anisotropy of the magnetic materials. The measured magnetic power loss under clockwise rotating fields differs from that of the counter‐clockwise direction, and the value in counter‐clockwise rotating fields sometimes becomes negative. It can be considered that angle errors of H‐coils and B‐coils are the main causes of the measurement errors. In this paper, the angle errors of the double B‐coil (search coils) and the double H‐coil (cross‐type H‐coil) are evaluated with a projector‐type magnifying scope and a calibration device. We have compensated the measured magnetic field vector components caused by the angle errors and made clear their influence on the two‐dimensional vector magnetic property measurements. Furthermore, we proposed a method to cancel out small angle errors that remained in the saturated region. Copyright © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.