Silicon steel sheets, a core material in AC motors, play a pivotal role in minimizing energy losses and enhancing performance. These sheets are alloyed with silicon (typically 1-5%) to reduce electrical conductivity, thereby curbing eddy current losses—a key factor in motor efficiency.
There are two primary types: grain-oriented (GO) and non-grain-oriented (NGO) silicon steel. GO sheets feature a highly ordered crystal structure, optimized for low magnetic loss when magnetized along the rolling direction. This makes them ideal for transformers and high-efficiency motors where unidirectional magnetic flux dominates. In contrast, NGO sheets have a random crystal orientation, allowing efficient magnetization in all directions. They are widely used in rotating motors, such as induction motors, due to their adaptability to multi-directional magnetic fields.
The link between silicon steel and motor efficiency is direct. Thinner sheets (0.2-0.3mm for GO, 0.3-0.5mm for NGO) reduce eddy current losses by limiting current circulation. Higher silicon content further lowers conductivity but increases brittleness, requiring careful balancing. Advanced NGO grades, with refined grain structures and reduced impurities, enable modern motors to meet strict efficiency standards like IE3 and IE4, cutting energy consumption by up to 20% compared to older designs. Thus, selecting the right silicon steel type is critical for achieving optimal motor efficiency.