Single phase pole mounted transformer: Efficient, durable, space-saving pole-top solution.
01 General
1.1 Project Description
75 kVA single phase pole mounted transformer was delivered to Guyana in 2025. The rated power of the transformer is 75 kVA with ONAN cooling. The high voltage is 13.8 kV with ±2*2.5% tapping range (NLTC), the low voltage is 0.12/0.24 kV, they formed a vector group of Ii0.
Designed and tested in accordance with IEEE and ANSI C57.12.00 standards. It is rated for 60Hz operation, with a high-voltage (HV) rating of 13.8kV and a low-voltage (LV) rating of 120/240V. This dual voltage output allows simultaneous supply of 120V for lighting and 240V for power or small commercial loads, making it an ideal choice for split-phase distribution systems commonly used in North America and other regions for residential, rural electrification, and light commercial applications.
The transformer telephone pole utilizes copper winding material for both HV and LV coils, offering high conductivity, excellent creep resistance, and strong short-circuit withstand capability for long-term reliability. The polarity is subtractive and the vector group is Iio, facilitating easy polarity matching when multiple transformers are operated in parallel or series. It is equipped with 5 no-load tap positions providing a tap range of ±2×2.5% (total range 10%), which effectively compensates for line voltage variations and allows voltage regulation under different load conditions.
In summary, this 75kVA transformer telephone pole combines compact construction, stable performance, low losses, wide tap range, and excellent lightning impulse withstand capability. It is an ideal solution for distribution networks requiring reliable and economical single-phase power supply, including rural electrification upgrades, suburban distribution, temporary power supply, and single-phase grid integration for photovoltaic or energy storage systems.
1.2 Technical Specification
75 kVA transformer telephone pole specifications type and data sheet
| Delivered to | Guyana |
| Year | 2025 |
| Type | Pole mounted transformer |
| Standard | IEEE & ANSI C57.12.00 |
| Rated Power | 75 kVA |
| Frequency | 60HZ |
| Phase | 1 |
| Polarity | Subtractive |
| Cooling Type | ONAN |
| Primary Voltage | 13.8 kV |
| Secondary Voltage | 0.12/0.24 kV |
| Winding Material | Copper |
| Angular displacement | Ii0 |
| Impedance | 2% |
| Tap Changer | ±2*2.5%(total range=10%) |
| No Load Loss | 0.214 kW |
| On Load Loss | 0.713 kW |
| Total loss | 0.927 kW |
| Basic lighting impulse (HV) | 95kV |
| Basic lighting impulse (LV) | 30kV |
1.3 Drawings
75 kVA transformer telephone pole diagram drawing and size.
02 Manufacturing
2.1 Core
| The transformer core is manufactured from high-grade, low-loss grain-oriented silicon steel. The core design minimizes hysteresis and eddy current losses, achieving a measured no-load loss of only 210 W (tested at rated voltage, 26°C ambient), well within IEEE C57.12.20 tolerance requirements. The core is precision-cut, annealed to relieve internal stresses, and rigidly clamped to withstand mechanical forces during transportation and long-term operation. |  |
2.2 Winding
 | Both high-voltage (13.8 kV) and low-voltage (120/240 V) windings are wound with high-purity copper (COPPER/COPPER), ensuring excellent conductivity, short-circuit withstand capability, and long-term reliability. The HV winding resistance was measured at tap positions (e.g., Tap 3: 57.279 Ω between H1-H2), and LV winding resistances were recorded (e.g., X1-X3: 0.003122 Ω). The transformer features 5 no-load tap positions with a range of ±2 × 2.5% (total 10%), allowing flexible voltage adjustment to compensate for line drops. |
2.3 Tank
| The tank is fabricated from mild steel with dimensions 1085 mm (H) × 735 mm (W) × 705 mm (L). It is designed for overhead pole-mounted installation with oil-immersed self-cooling (ONAN). The tank is equipped with 2 HV bushings and 3 LV bushings (subtractive polarity, vector group Iio). A 20 kPa pressure leakage test was conducted for 12 hours with no leakage and no permanent deformation, confirming the tank’s sealing integrity. |  |
2.4 Final Assembly
 | During final assembly, the core-winding assembly is carefully dried and vacuum-impregnated with high-grade insulating oil (total oil weight: 81 kg). All internal connections, tap changer, bushings, and external components (lifting lugs, ground terminals, nameplate, mounting brackets) are securely installed. The complete assembly is filled with oil under vacuum to eliminate air pockets, ensuring reliable dielectric performance. |
03 Testing
| No. | Test Item | Unit | Acceptance Values | Measured Values | Conclusion |
| 1 | Resistance Measurements | / | / | / | Pass |
| 2 | Ratio Tests | / | The deviation of voltage ratio on the principal tapping: ≤0.5% Connection symbol: Ii0 | 0.00 | Pass |
| 3 | Polarity tests | / | Subtractive | Subtractive | Pass |
| 4 | No-load losses and excitation current | % Kw A | I0 :: provide measured value P0: provide measured value the tolerance for no load loss is +10% I0 :: 根据测量值 P0: 根据测量值 空载损耗偏差+10% | 0.54 0.210 1.688 | Pass 合格 |
| 5 | Load losses, impedance voltage, total losses and efficiency | / kW kW | t:85℃ Z%: measured value Pk: measured value Pt: measured value the tolerance for impedance is ±10% the tolerance for total load loss is +6% | 2.08 0.713 0.923 99.02 | Pass |
| 6 | Applied Voltage Test | / | HV：34KV 60s LV: 10kV 60s | No collapse of the test voltage occurs | Pass |
| 7 | Induced Voltage Withstand Test | / | Applied voltage (KV): 2 Ur Duration(s): 40（50HZ）/48（60HZ） Frequency (HZ): 150 | No collapse of the test voltage occurs | Pass |
| 8 | Insulation Resistance Measurement | GΩ | HV-LV to Ground LV-HV to Ground HV&LV to Ground | 85.9 39.4 40.2 | Pass |
| 9 | Leakage Test | / | Applied pressure：20kPA Duration：12h | No leakage and no Damage | Pass |
| 10 | Oil Dielectric Test | kV | ≥45 | 64.62 | Pass |
04 Packing and Shipping
4.1 Packing
Before packing, the transformer telephone pole is securely drained (or shipped with oil per customer request). All bushings and accessories are protected with moisture-proof caps. The transformer is fastened to a heavy-duty wooden pallet or steel skid, cushioned with foam padding, and enclosed in an export-grade plywood crate. A waterproof pouch containing the test report, nameplate details, and handling instructions is attached to the outside.
4.2 Shipping
The transformer telephone pole is suitable for sea, air, or land transport. Packed dimensions are slightly larger than the tank (1085×735×705 mm). Total shipping weight is 361 kg (including 81 kg of insulating oil). The transformer is rated for operation at altitudes up to 2500 m and ambient temperatures up to 45°C, making it adaptable to various climatic conditions. Proper labeling (center of gravity, lifting points, fragile, this side up) is applied to the crate.
05 Site And Summary
In summary, our single-phase pole-mounted transformers are engineered to deliver reliable, efficient, and safe power distribution for residential, agricultural, and light commercial applications. With robust construction, superior voltage regulation, and easy pole-mount installation, they provide a cost-effective solution for extending electrical networks in both rural and urban settings.
Backed by rigorous quality testing and compliance with ANSI/IEEE standards, each transformer ensures long-term performance with minimal maintenance. Whether you are upgrading an existing grid or expanding to new service areas, our transformers offer the durability and dependability you need.
Contact our team today to learn more or request a customized quote. Choose quality – choose reliability – power ahead with confidence.
