R-core is unique type of core designed and developed by Japanese engineers. These cores are manufactured in the conventional rectangular shape but the slitting is done by a special process, ensuring high stacking factor. The special heat treatment, continuous strip and no gap ensure higher efficiency to the transformers.
The cores are manufactured using M4 & M2H grade material of 0.23 / 0.27 mm thickness and available in various standard sizes.
R-core Transformers are manufactured using the unique rectangular core with round cross section known as R-core. The special feature of this transformer is that the core is gap less and continuous. The winding is done on special round bobbins on two parallel legs of the core. In comparison with EI Transformers of same capacity, the R-core transformer is COMPACT (nearly 40% smaller) and has a LOW TEMPERATURE ELEVATION.
Further the LEAKAGE FLUX of the transformer IS VERY LOW (about 1/10th of conventional transformers), which permits the equipment manufacturer to place the transformer close to critical electronic components. The balanced winding & low leakage flux ensures LOW NOISE of the transformers. This gives a cutting edge to the transformer for use in test equipment, audio & video amplifiers & other noise sensitive equipment.
The other unique feature is the use of Bobbins in two parts. The primary winding and secondary winding are done on separate bobbins thus ensuring complete isolation between the two windings. This allows meeting of any safety standards requirement.
The R-core Transformers have found wide application in CRT display units, Audio equipments, Satellite receivers, Printers, Photo-copier machines, weighing scales and many more.
1. The special characteristic of the R-core transformer is the ability of the two coils to mutually cancel each other's magnetic flux by means of balanced, symmetrical winding of the coils. With this winding method the leakage flux can be kept to a minimum amount. The key point is the exact balance of the two coils.
2. The R-core transformer has absolutely no gap in its magnetic paths. On the other hand, the EI-type has a magnetic gap in 6 locations, and the CI or the cut core type has 2 to 4 magnetic gaps. A great deal of leakage flux escapes from these magnetic gaps.
3. The R-core transformer makes a maximum use of the superior material properties of the Z-H grain-oriented silicon steel. As a result, the core's magnetic resistance is very low, and the cross section of the magnetic path is uniform. The exciting current of the R-core transformer is lower than the EI-type ensuring that the leakage flux is minimal and a higher percentage of the entire magnetic flux of the R-core transformer is being put to much more effective use.