The series of products in the design is more advanced, in the material, structure and process has been greatly improved and improved. The high and low pressure clamps are tightened with copper draw bands or upper and side beams to form a strong frame structure, which enhances the clamping force of the iron core and the ability to withstand transportation impact. Strong short-circuit resistance, beautiful appearance selection, reliable operation, low loss, low noise, to the advanced level of similar foreign products.