Engineered for durability, designed for performance—pad mounted transformers lead the way.
01 General
1.1 Project Description
4390 kVA three phase pad mounted transformer was delivered to Jamaica in 2025. The rated power of the transformer pad mount 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 0.69D kV, they formed a vector group of YNd1.
Designed for reliable outdoor power distribution in commercial, industrial, and infrastructure applications, this 50Hz three-phase three-limb transformer pad mount integrates advanced materials, efficient electrical performance, and robust corrosion resistance-constructed with 304 stainless steel for durability and a C5M corrosion resistance class, complemented by a powder-coated white finish (RAL 9003) that preserves aesthetic integrity and enhances weather protection-while featuring FR3 dielectric fluid for superior fire safety, environmental compatibility, and thermal stability, alongside a dedicated grounding shield and isolation screen grounding sleeve to suppress electromagnetic interference, mitigate partial discharge risks, and ensure reliable insulation. Boasting a high efficiency rating of 99.2% to minimize energy loss and a 7.5% short-circuit impedance for effective fault current limitation, it delivers optimized operating capacity across temperature variations (4330kVA at 45℃ and 4075kVA at 50℃), combining rugged construction, advanced safety features, and consistent performance to meet rigorous operational demands in diverse climatic and environmental conditions.
1.2 Technical Specification
4390 kVA transformer pad mount 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 | 0.63 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 pad mount diagram drawing and size.
02 Manufacturing
2.1 Core
| The robust three-limb core design ensures long-term reliability under demanding conditions. By minimizing performance degradation, it protects your investment and significantly reduces the risk of costly downtime, guaranteeing a stable power supply for years to come. |  |
2.2 Winding
 | Built with 100% copper – HV foil for robust stability, LV wire for optimal conductivity. This construction withstands thermal stress and fault conditions, significantly reducing failure risks and protecting your investment from costly downtime. |
2.3 Tank
| Built with 304 stainless steel and C5M anti-corrosion grade, our tank outlasts conventional carbon steel units. The maintenance-free white finish guarantees 30+ years of reliable service, protecting your investment where others would fail. |  |
2.4 Final Assembly
 | Precisely assembled and rigorously tested, every transformer integrates proven components into a ready-to-deploy unit. This ensures immediate, trouble-free operation from day one, eliminating commissioning risks and delivering long-term reliability. |
03 Testing
Designed to meet your demand for dependability and cost-effectiveness, our three-phase pad mounted transformer undergoes rigorous testing that goes beyond basic requirements. Complying with international IEC standards, key tests include 150Hz induced voltage withstand (40s), precise insulation resistance measurement, and a strict leak test (no leakage/deformation). Critical data like voltage ratio deviation (-0.03%~-0.01%, well within ±0.5%), ultra-low no-load current (0.22%), and stable short-circuit impedance (7.12%) prove its superior performance. We ensure our product not only meets but exceeds your expectations for operational stability, safety, and long-term value.
| No. | Test Item | Unit | Acceptance Values | Measured Values | Conclusion |
| 1 | Resistance Measurements | % | Maximum resistance unbalance rate | 3.82 | Pass |
| 2 | Ratio Tests | % | The deviation of voltage ratio on the principal tapping: ≤0.5% Connection symbol: YNd1 | -0.03% ~- 0.01% | Pass |
| 3 | phase-relation tests | / | YNd1 | YNd1 | Pass |
| 4 | No-load losses and excitation current | / | I0 :: provide measured value | 0.22% | Pass |
| P0: provide measured value | 3.429kW | ||||
| 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 | 7.12% | ||||
| Pk: measured value | 27.924kW | ||||
| Pt: measured value | 31.353kW | ||||
| Efficiency not less than 99.2% | 99.29% | ||||
| 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 | 1.92 | / |
| LV-HV to Ground | 1.31 | ||||
| HV&LV to Ground | 0.902 |
04 Packing and Shipping
4.1 Packing
| Our commitment to quality extends to delivery. The professional wooden crate packaging not only safeguards your critical asset from the rigors of logistics but also reflects our thorough attention to detail. It guarantees a flawless product is handed over to you, ensuring a smooth and efficient project start. |  |
4.2 Shipping
 | Your transformer’s secure DDU delivery to Norman Manley International Airport is our commitment. We guarantee its integrity with robust, custom-built wooden crating and strict compliance with international transport regulations for high-value electrical equipment. Our proven expertise in handling complex logistics to destinations like KIN, including pre-cleared customs formalities, eliminates your operational uncertainties and safeguards your project timeline, ensuring a risk-free handover at the agreed point. |
05 Site And Summary
As you plan for the critical infrastructure that powers your community or business, the decision extends beyond a simple purchase. It’s an investment in decades of reliable performance. By choosing our transformer pad mount, you are not just acquiring a superior product with proven efficiency and a long design life; you are gaining a dedicated partner. Our global manufacturing footprint and localized technical support ensure that we are there with you from seamless installation through the entire lifecycle, minimizing your total cost of ownership. Make the secure, long-term choice. Partner with us to build a more resilient and efficient energy future.
