Precision Transformer Engineering
Spark Engineering Technology Bangladesh manufactures premium oil-immersed distribution transformers ranging from 50 kVA up to 3000 kVA (and custom power ratings up to 33kV/36kV). Designed in strict compliance with IEC-76, BS-171, VDE 0537, and ANSI C57.12, our transformers combine maximum energy efficiency with exceptionally low no-load and full-load losses.
Core Technical Architecture:
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CRGO Core (Imported Japan): High permeable cold-rolled grain-oriented silicon steel sheet step-lap miter cut to eliminate air gaps, reduce excitation currents, and minimize humming.
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Copper Windings: High-conductivity electrolytic copper pinhole-free super enameled wire for HV windings; pure cellulose insulated copper strip for LV windings.
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Cooling Dynamics (ONAN / ONAF): Deep corrugated fins or pressed-steel radiators chemically processed to prevent internal corrosion, filled with Savita IEC 296 Class 1 dielectric transformer oil.
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Heavy Lamination-Free Steel Tank: Sand-blasted steel tanks treated with three-coat zinc-rich primer and protective paint coating exceeding 140 μm thickness.
11/0.415kV Distribution Transformer Performance Table
Standard ratings and technical dimensions for Bangladesh power conditions (50Hz, 3-Phase, Dyn11 Vector Group):
| Capacity | No-Load Loss | Load Losses | % Impedance | Full Load Eff. | Dimensions (H x L x W cm) | Oil Capacity | Total Weight |
|---|---|---|---|---|---|---|---|
| 50 kVA | 155 W | 840 W | 4.0 % | 98.05 % | 75 x 85 x 35 | 150 L | 750 kg |
| 100 kVA | 240 W | 1340 W | 4.0 % | 98.57 % | 132 x 100 x 65 | 221 L | 850 kg |
| 150 kVA | 360 W | 2000 W | 4.0 % | 98.47 % | 145 x 105 x 88 | 220 L | 900 kg |
| 200 kVA | 380 W | 2250 W | 4.0 % | 98.37 % | 150 x 112 x 93 | 300 L | 975 kg |
| 250 kVA | 460 W | 2900 W | 4.5 % | 98.48 % | 158 x 123 x 95 | 270 L | 1100 kg |
| 315 kVA | 540 W | 3200 W | 4.5 % | 98.38 % | 157 x 120 x 97 | 400 L | 1250 kg |
| 400 kVA | 650 W | 4250 W | 4.5 % | 98.44 % | 162 x 123 x 98 | 475 L | 1450 kg |
| 500 kVA | 790 W | 4980 W | 5.0 % | 98.57 % | 165 x 124 x 102 | 550 L | 1725 kg |
| 630 kVA | 910 W | 6000 W | 6.0 % | 98.62 % | 170 x 136 x 103 | 620 L | 2025 kg |
| 750 kVA | 920 W | 6600 W | 6.0 % | 98.66 % | 185 x 155 x 112 | 675 L | 2300 kg |
| 800 kVA | 990 W | 7100 W | 6.0 % | 98.61 % | 225 x 170 x 113 | 725 L | 2625 kg |
| 1000 kVA | 1180 W | 8200 W | 6.5 % | 98.67 % | 215 x 185 x 115 | 850 L | 2900 kg |
| 1250 kVA | 1360 W | 10000 W | 6.5 % | 98.87 % | 225 x 190 x 116 | 1150 L | 3850 kg |
| 1500 kVA | 1630 W | 12400 W | 6.5 % | 98.97 % | 230 x 200 x 120 | 1300 L | 4450 kg |
| 2000 kVA | 1950 W | 15500 W | 6.5 % | 99.04 % | 250 x 210 x 135 | 1700 L | 4900 kg |
| 2500 kVA | 2350 W | 18000 W | 7.0 % | 99.08 % | 285 x 220 x 150 | 2200 L | 6800 kg |
| 3000 kVA | 2950 W | 24500 W | 7.0 % | 99.08 % | 290 x 230 x 160 | 2700 L | 7500 kg |
Transformer Protection Accessories
Every unit is equipped with certified instrumentation to safeguard against overpressure, overheating, and insulation degradation:
Buchholz Relay
Installed between main tank and conservator. Detects slow gas accumulation from micro-arcing and trips immediately on sudden oil surges.
Pressure Relief Valve (PRV)
Spring-loaded hermetic valve venting sudden overpressure spikes caused by internal short-circuit faults before tank deformation occurs.
Silica Gel Dehydrating Breather
Directional air breather with liquid oil seal stripping atmospheric humidity before air enters the conservator expansion vessel.
Savita Class 1 Dielectric Oil
Tested in-house for breakdown voltage (BDV > 40kV), dissipation factor (Tan δ), flash point, pour point, and moisture content.
BSTI & BUET Approved Quality Testing Laboratory
Our test bay is certified by BSTI, BUET, and the Electrical Licensing Authority of the Ministry of Energy. Every transformer manufactured undergoes mandatory routine tests before shipment: