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Name:3-D Open Core

Technical advantages:
1. Transformer manufacturers can form 3D open type cores very easily and manufacture new transformers. 
2. In case of failure of transformer at any time, top yokes can be easily removed and coils can be easily replaced (similar to stacked core). 
3. Saving in overall transformer cost (upto 7% depending on transformer rating, voltage class, losses, etc).
4. Very low Harmonics – very much needed for modern living with electronic gadgets.  
5. Very low inrush current – very good to protect transformers where power “on” and “off” is very frequent.
6. Very low magnetizing current and no load loss compared to other designs of silicon steel (stacked core and wound core).
7. Highly accepted for Windmills power generation 
8. Withstands unbalanced loads 
9. Due to circular cross section of core – utilization factor is almost 96%. Hence less consumption of winding materials
10. Due to circular in shape – much better short circuit withstanding capabilities for transformers
11. Very easy to form 3D open type cores 
12. Almost NO wastage of silicon steel during 3D open type core processing (less than 1% depending on manufacturing practices)
Manufacturing advantages:
1. Transformer manufacturers can use their “single coil” manufacturing coil winding machines. No special coil machines needed and training are required. No additional investment.
2. Core and coils are processed separately. Saves production time and investment on special coil winding machines. 
3. Available silicon steel core annealing furnaces can be used to anneal open type 3D cores. No additional investment.
4. Operators can be trained easily in a very short time (2 to 3 days)
Process of making 3D open type core transformers:
1. Prepare 3D transformer design as per your requirements. If you give order for our machines, we will give you sample transformer design sheet in pdf (say 500 kVA, 11 kV / 0.433 V) for your reference.
2. Get slit silicon steel rolls as per design (normally 7 widths of steel)
3. Make slitting using our special cure slitting machines and wind onto steel bobbins
4. Load slit core on 3D core machine decoiler and make 3D open type core
5. Assemble core on special 3D core forming jig
6. Anneal 3D open type cores
7. Fix annealed cores on core frames
8. Open top yoke
9. Insert coils and insulation
10. Reassemble top yoke
11. Make HV and LV connections
12. Vacuum / air drying in hot air heating chambers
13. Tanking and oil filling
14. Testing
As per your request, we are herewith attaching detailed technical specifications of the entire set of machinery.
1. Specification of curve slitting machine
2. Specifications of open type 3D core forming machine with de-coiler
3. Special 3D core assembly jig for transformers upto 500 kVA
4. Special 3D core assembly jig with motorized tilting arrangement – suitable for transformers upto 5000 kVA