Choose pad mounted transformers for efficient, compact energy distribution.
01 General
1.1 Project Description
4390 kVA three phase pad mounted transformer was delivered to Jamaica in 2025. The rated power of the pad mount transformer is 4390 kVA with ONAN cooling. The high voltage is 23.9GrdY/13.8 kV with ±2*2.5% tapping range (NLTC), the low voltage is 0.63D kV, they formed a vector group of YNd1.
Engineered for superior performance in modern electrical networks, our 4390 kva transformer delivers exceptional reliability and efficiency. This robust unit features a three-phase, three-limb core optimized for 50Hz operation, achieving an impressive 99.2% efficiency with a 7.5% impedance for stable grid performance. Filled with eco-friendly FR3 dielectric fluid, it enhances fire safety and operational longevity. Critical to its design are the integrated Grounding Shield and Isolation Screen Grounding Sleeve, which ensure maximum safety by effectively containing electromagnetic interference and protecting personnel. Housed in a resilient 304 stainless steel enclosure finished in a corrosion-resistant, C5M-grade white powder coat (RAL 9003), it is built to endure the most demanding environmental conditions.
With a robust operational capacity of 4330kVA at 45°C and 4075kVA at 50°C, this transformer stands as a secure, durable, and intelligent cornerstone for your power distribution infrastructure.
1.2 Technical Specification
4390 kva transformer specifications type and data sheet
| Delivered to | Jamaica |
| Year | 2025 |
| Type | Pad mounted transformer |
| Standard | IEC 60076 |
| Rated Power | 4390 kVA |
| Frequency | 50HZ |
| Phase | 3 |
| Feed | Loop |
| Front | Dead |
| Cooling Type | KNAN |
| Primary Voltage | 23.9GrdY/13.8 kV |
| Secondary Voltage | 0.69 kV |
| Winding Material | Copper |
| Vector Group | YNd1 |
| Impedance | 7.5% |
| Efficiency | 99.2% |
| Tap Changer | NLTC |
| Tapping Range | ±2*2.5% |
| No Load Loss | 3.95 kW |
| On Load Loss | 28 kW |
1.3 Drawings
4390 kva transformer diagram drawing and size.
02 Manufacturing
2.1 Core
| Our three-limb core, crafted from premium silicon steel, is engineered for maximum energy savings and minimal noise. It directly delivers lower electricity bills and quiet operation, making it an ideal, neighbor-friendly choice for cost-effective and sustainable power distribution. |  |
2.2 Winding
 | Our all-copper winding system combines HV foil and LV wire for maximum efficiency and heat resistance. This superior design ensures lower energy loss, enhanced short-circuit strength, and extended transformer life – delivering true value through reduced operating costs. |
2.3 Tank
| Our 304 stainless steel tank with C5M protection withstands harsh environments effortlessly. The durable white finish stays clean and corrosion-free for decades, eliminating maintenance costs and ensuring worry-proof operation in coastal or industrial areas. |  |
2.4 Final Assembly
 | Our final assembly ensures perfect synergy between the high-efficiency core, all-copper windings, and stainless steel tank. This precision integration delivers guaranteed performance with lower lifetime costs, providing decades of maintenance-free operation. |
03 Testing
Tailored to your core needs for reliability, efficiency, and quality transparency, our 4390 kva transformer undergoes comprehensive testing that goes beyond basic compliance. Following IEC standards, key tests include precise winding resistance checks (max unbalance rate 4.59%), low no-load loss (3.564kW), robust dielectric withstand, and 24-hour leak-proof verification. We stand out by delivering measurable excellence: 99.28% efficiency (exceeding the 99.2% minimum), consistent phase relation (YNd1). We offer clear, actionable test data and prompt inquiry support, giving you the confidence that your transformer is energy-efficient, durable, and backed by a manufacturer committed to your operational success.
| No. | Test Item | Unit | Acceptance Values | Measured Values | Conclusion |
| 1 | Resistance Measurements | % | Maximum resistance unbalance rate | 4.59 | Pass |
| 2 | Ratio Tests | % | The deviation of voltage ratio on the principal tapping: ≤0.5% Connection symbol: YNd1 | -0.05% ~ -0.03% | Pass |
| 3 | phase-relation tests | / | YNd1 | YNd1 | Pass |
| 4 | No-load losses and excitation current | / | I0 :: provide measured value | 0.23% | Pass |
| P0: provide measured value | 3.564kW | ||||
| the tolerance for no load loss is +15% | / | ||||
| 5 | Load losses impedance voltage and efficiency | / | t:75℃ the tolerance for impedance is ±10% the tolerance for total load loss is +10% | / | Pass |
| Z%: measured value | 7.06% | ||||
| Pk: measured value | 28.162kW | ||||
| Pt: measured value | 31.726kW | ||||
| Efficiency not less than 99.2% | 99.28% | ||||
| 6 | Applied Voltage Test | kV | LV/: 10kV 60s | No collapse of the test voltage occurs | Pass |
| 7 | Induced Voltage Withstand Test | kV | Applied voltage (KV):2Ur | No collapse of the test voltage occurs | Pass |
| Duration(s):40 | |||||
| Frequency (HZ): 150 | |||||
| 8 | Leakage Test | kPa | Applied pressure: 50kPA | No leakage and no Damage | Pass |
| Duration: 24h | |||||
| 9 | Insulation Resistance Measurement | GΩ | HV-LV to Ground | 1.87 | / |
| LV-HV to Ground | 1.15 | ||||
| HV&LV to Ground | 0.832 |
04 Packing and Shipping
4.1 Packing
| We ship every unit in custom-built wooden crates, engineered for maximum protection during transit. This robust packaging ensures your transformer arrives on site in perfect, ready-to-install condition, eliminating the financial risks and project delays associated with transportation damage. |  |
4.2 Shipping
 | We expertly manage the entire DDU transport chain of your three-phase pad-mounted transformer to PAC Kingston Airport Ltd. (KIN). Our meticulous planning, from specialized wooden-crate packaging that exceeds industry standards to navigating KIN’s specific cargo protocols and 24/7 electronic customs, ensures your critical asset arrives safely and on schedule. This seamless, hassle-free delivery to your specified destination mitigates the risks of damage and project delays, providing you with absolute peace of mind. |
05 Site And Summary
When your project’s success depends on unwavering power supply and on-schedule delivery, you need certainty in your equipment and your supplier. Our three-phase pad mounted transformers are engineered for exactly that-delivering unmatched reliability to keep your operations running. But our advantage goes further: it’s our commitment to your timeline. With rigorous pre-delivery testing and a streamlined global supply chain, we ensure your transformer arrives on site as promised, ready for a trouble-free installation. Don’t let operational risks or delays jeopardize your project. Choose the confidence that comes with our proven track record and specify the transformer trusted by utilities and industries worldwide.
