1) lap winding core The lapped winding core was first used in amorphous alloy distribution transformers. The utility model has the advantages of winding magnetic core, small excitation current and low no-load loss, and can open the loading and unloading coil, thereby eliminating the disadvantage of the general winding magnetic core, and does not need to use
a special winding machine to wind the coil, and the production efficiency is improved, and the coil appears. It is also easy to replace and repair when the problem occurs. The thickness of the existing 3% oriented silicon steel has been reduced to 0.23 mm and 0.27 mm, and it is easier to manufacture the lapped wound core than the amorphous alloy. Therefore, the
lapped winding core is likely to be used for silicon steel power transformers of 500 VA or higher, especially for silicon power transformers in large-capacity rectified power supplies and uninterruptible power supplies.
2) Three-dimensional triangular core The three-dimensional triangular core of the three-dimensional arrangement is now popular in China. The earliest three-dimensional triangular cores can be traced back to the 1930s. However, because the cores require special shearing, the coils need to be wound by a special winding machine, which has not been popularized.
It is now possible to control the magnetic core shearing process with a computer, and there is already a dedicated winding machine winding. There are 5-6 companies in China that apply for a patent for a three-dimensional triangular core transformer. Compared with the three-column three-phase magnetic core arranged in a plane, the three-dimensional magnetic core
of the three-dimensional arrangement has a uniform magnetic flux distribution, no local saturation, and good symmetry of the excitation current and the magnetic flux. The problem is that it is quite difficult to form a cross section of each column to be close to a circle, and the average winding length of the winding increases, and the load loss also increases.
Can be used for large transformers above 30kVA.