For silicon steel, it’s very easy to make the core by stacking thin stamp parts together. But for brittle amorphous or nanocrystalline, this in not suitable and tape winding is the basic manufacturing technical. Therefore, the height of a tape wound core is limited to a series of numbers.
Laminated or Tape Wound Soft Magnetic Core
One typical tranditional soft magnetic core is laminated core, which is made by stacking a number of thin metal plates, which are punched from a large sheet of electrical steel. In order to reduce the eddy current and core loss, each piece of the metal plates should be very thin. The widely used “EI” shape transformer cores are made by such method.
But we cannot punch the amorphous or nanocrystalline by stamping die. So, we manufacture the amorphous or nanocrystalline cores by winding very thin tapes or ribbons with thickness range from 0.018mm to 0.035mm. This process can be handled manually, or by automatic winding machines, as introduced in the article below.
According to the manufacturing technical, we can make solid or split cores of different shapes, like toroidal, rectangular (oblong), or oval cores, all of which can be used to make current transformers. By special technical and construction, “E” type tape wound cores are also available. The height of a finished tape wound core is determined by the width of the ribbon, which ranges from 3mm to 50mm. So, “non-standard” height, say 19mm, are not recommended in practice.