20KV (22kv) Dry-type Distribution Transformer

1. Low-loss cold-rolled silicon steel core The core is built from low-loss cold-rolled grain-oriented silicon steel, a material chosen for its magnetic performance together with its mechanical strength.
2. 45° mitred step-lap joints, cut and stacked in steps The joints are cut as a 45° mitre and built as a step-lap: corner trimming and cross-cutting on a three-cut, two-punch process, then stacked with a five-step progressive sequence. The flux crosses the joint more smoothly, and the core carries less vibration energy.
3. Even flux distribution — lower no-load and load loss, higher efficiency With the flux path even across the core, both no-load loss and load loss come down noticeably. That shows up as a high energy-efficiency grade and a real saving on running energy.
4. Low reluctance — quieter running, and strength under short circuit Low reluctance holds down vibration and noise in service, and the unit is built to take the shock of a high short-circuit current so that it keeps running safely.

Built for a wide range of industrial duty — for industrial environments across the board, including power distribution.  

1. Customization is driven by the technical specification

Every order begins with the project's technical conditions — rated capacity, voltage combination, tapping arrangement, vector group, impedance voltage, insulation level, cooling method and the ambient conditions at the installation. These are confirmed item by item and issued as an approved drawing set. Production does not start until that drawing set is signed back.

2. Parameters open to customization

Electrical

• Rated capacity: 30–5000 kVA, any step within the range
• Voltage class: 6.6 kV–35 kV, with the primary and secondary combination set by the project
• Vector group: Dyn11 or to specification
• Tapping arrangement: off-circuit taps, e.g. ±2×2.5% or ±5%
• Impedance voltage, insulation level and temperature-rise limit to the specification

Construction and environment

• Insulation class F / H, and cooling by natural air (AN) or forced air (AF)
• Enclosure and degree of protection selected for the installation environment
• Overall dimensions, terminal positions and cable-entry direction, dimensioned to suit your electrical room
• Finish, nameplate data, manual and documentation language
• Export packing and shipping marks

3. The manufacturing capability behind the customization

Coil winding in-house

• — windings are wound on our own winding machines by our own operators; the winding is not subcontracted

Insulation fabricated and fitted to the drawing

• — cylinders, spacers and barriers are cut, formed and fitted to the voltage class and winding layout of each order

Core, coils and assembly in one works

• — core building, coil fitting and clamping are carried out in the same plant, with overhead crane handling for the larger frames

Inspection against the unit's own sheet

• — every unit is checked against its own inspection sheet before packing

4. Tested and documented before dispatch

Each unit is routine-tested before packing, and the unit documents travel with the shipment, so the parameters that arrive on site are the parameters that were approved on the drawing.

5. How a custom order proceeds

Stage	What happens
1. Technical clarification	Project conditions and parameters are reviewed with you
2. Technical agreement	Parameters confirmed item by item and frozen
3. Drawing approval	The drawing set is issued to you and signed back
4. Production	Winding, core building, fitting and assembly to the approved drawing
5. Routine test	Each unit tested and checked against its own inspection sheet
6. Packing and dispatch	Export packing, markings and documentation