Investigating effects of applied mechanical and thermal processes of grain-oriented silicon electrical steels on no-load losses of transformer

Transformers are one of the important machineries of electrical transmission lines. Faraday Law which is one of the main laws of magnetism transformed a technological device by scientific inventions and empirical research along almost 200 years and improvements has been continuing. Electricity generation and utilizing phenomena is not going to change and transformers will stay as very important infrastructure elements of modern ages until a stunning conceptual invention takes place in science and industry. In this thesis, to the name of improving a more efficient electric transmission and transformation equipment, a minor contribution on transformer core steels processing area is aimed. As a part of core manufacturing processes of transformers, angled shear cutting process is researched academically as possible as detailed to understand effects on magnetic properties of core steel individually deterioration and recovering on iron loss parameter of core steel. For these purposes, shear cutting process which is known very traditionally in industry analyzed with defined process parameters modelled statistically in which regression coefficient calculated as R2= 0,9896. EBSD, EDX, XRD analyzes, and micro-hardness measuring applied in vicinity of cut edges, by this way, crystallographic textures and plastic deformation affected zones of cut edges observed in level of crystallography. As-cut vs. annealed form of standard and non-standard M5 grade EPSTEIN test samples measured and compared regarding to iron loss parameters and, ratio of 3.7-6.4% recovery of iron loss is reported. With the promotion of iron loss recovering results on test samples, rated as 40 kVA 4 pieces identical cast resin dry type transformer core legs and yokes are designed, sheared and, 2 of them are annealed under vacuum at 750 ⁰C for 3 hours. Regarding comparation results of prototype cores having centering holes, 14.5-16.5% iron loss recovery observed on annealed cores.