Influence of stress on rotational loss in silicon iron

The stress sensitivity of rotational-power loss in silicon iron has been investigated. The loss increases with tensile stress applied parallel to the rolling direction and decreases with compression. The opposite occurs when the stress is applied perpendicular to the rolling direction. The loss varies in a similar fashion over the flux-density range investigated. Increasing the frequency causes the loss to rise drastically and also increases its stress sensitivity. It has also been shown theoretically that the angle of lag of the flux density behind the applied field increases with stress and varies during the magnetising cycle.