R core transformer is a new type transformer based on the advantages of C type and ring transformer. The "R-Core" made of high B material is completely non-cut core, thus reducing the overall magnetic flux leakage. It has round section, which shows that the high performance and smaller size. R type transformer is superior to the traditional E type transformer: 30% smaller, 40% thin, 40% lighter, less loss, lower temperature rise and lower noise. Simple structure, commonly used horizontal structure, thin shape, suitable for high density installation. R type transformer is widely used in high precision NC machine tools, medical products, television camera and audio equipment medium.