Dimensional factors affecting magnetic properties of wound cores

• Published in: Physica scripta 1989-08, Vol.40 (2), p.249-251
• Main Authors: Moses, A J, Ling, P C Y
• Format: Article
• Language: English
• Subjects: Applied sciences; Electrical engineering. Electrical power engineering; Exact sciences and technology; Transformers and inductors
• ISSN: 1402-4896; 0031-8949; 1402-4896
• DOI: 10.1088/0031-8949/40/2/017

The magnetic properties of wound cores constructed from electrical steel strips have been found to be affected by their geometry, in particular the inner and outer diameters, the strip width and the build-up thickness of the toroids. Assessment of the effect of aspect ratio and winding ratio have been carried out in various sizes of toroid. An increase in aspect ratio resulted in better magnetic properties, whereas increase in winding ratio degraded the original magnetic properties. However, when inner and outer diameters are varied with constant build-up and strip width, better performance is obtained by increasing the winding ratio. The initial rate of temperature technique using thermistors was used to measure power loss on the inner and outer wraps of a wound toroid. The power loss of 60 x 44 x 40 mm toroid at 1.0 T before stress relief annealing was 0.88 and 0.52 W kg exp --1 at the inner and outer layers respectively. After stress relief annealing, the power loss fell to 0.44 and 0.43 W kg exp --1 at the inner and outer layers respectively. This indicates the higher stress produced by small diameter wrapping can be reduced by normal stress relief annealing. 4 ref.--AA