Minimize Loss, Maximize Output – Smart Pole Mounted Transformers!
01 General
1.1 Project Description
37.5 kVA single phase pole mounted transformer was delivered to Canada in 2025. The rated power of the transformer is 37.5 kVA with ONAN cooling. The primary voltage is 2.4 kV with ±2*2.5% tapping range (NLTC), the secondary voltage is 0.12/0.24 kV, they formed a vector group of Ii6.
This 37.5kVA single-phase pole-mounted transformer is designed for efficient and flexible power distribution in outdoor applications, featuring a high-voltage (HV) bushing and three low-voltage (LV) bushings with 4-hole spade-type terminals for secure, high-current connections. The HV side incorporates an off-circuit tap changer (±2.5% adjustment range), allowing voltage regulation when de-energized, while the multi-tap LV configuration supports versatile load distribution. Built with robust insulation and a compact, pole-mountable structure, this unit is ideal for rural electrification, street lighting, and small-scale industrial use, offering low losses and reliable performance under standard grid conditions. Proper operation requires de-energized tap adjustments and routine maintenance of bushings and terminals.
1.2 Technical Specification
37.5 kVA pole mounted transformer specifications type and data sheet
| Delivered to | Canada |
| Year | 2025 |
| Type | Pole mounted transformer |
| Standard | CSA C2.2-06 |
| Rated Power | 37.5 kVA |
| Frequency | 60HZ |
| Phase | 1 |
| Polarity | Additive |
| Cooling Type | ONAN |
| Primary Voltage | 2.4 kV |
| Secondary Voltage | 0.12/0.24 kV |
| Winding Material | Aluminum |
| Angular displacement | Ii6 |
| Impedance | 2.7% |
| Tap Changer | NLTC |
| Tapping Range | ±2*2.5% |
| No Load Loss | 0.078 kW |
| On Load Loss | 0.720 kW |
| Efficiency | 98.73% |
1.3 Drawings
37.5 kVA pole mounted transformer diagram drawing and size.
02 Manufacturing
2.1 Core
 | The wound silicon steel core in single-phase pole-mounted transformers utilizes high-grade grain-oriented silicon steel, featuring seamless construction and low magnetic reluctance. This design reduces no-load losses and operational noise while achieving over 98% efficiency. The stepped-lamination structure optimizes magnetic flux distribution, making it ideal for demanding overhead distribution applications. |
2.2 Winding
| The transformer coil in single-phase pole-mounted transformers consists of multiple layers of insulated flat/round copper conductors, interleaved with high-voltage dielectric materials (e.g., Nomex or DMD). This design ensures even heat dissipation, high mechanical rigidity, and short-circuit resistance, while optimized interlayer capacitance suppresses harmonic distortion. |  |
2.3 Tank
 | The bunded oil tanks is made of durable steel, designed to withstand outdoor conditions while providing effective cooling and insulation for the internal components. The tank is filled with insulating oil that serves as both a coolant and dielectric medium. Mounting brackets are integrated for secure installation on utility poles. |
2.4 Final Assembly
| 1. Winding Assembly: Slide the HV/LV windings onto the laminated core, ensuring proper alignment and insulation integrity. 2. Electrical Connections: Connect winding leads to tap changer, bushings, and other components, then secure and insulate the joints. 3. Core-Coil Drying: Place the assembled active part (core + windings) into a drying oven for vacuum heating to remove moisture. 4. Tank Installation: Hoist the dried active part into the tank, position it securely, and ensure proper insulation from the tank walls. 5. Accessory Mounting: Install bushings, pressure relief valve and other accessories, then check for leaks. 6. Oil Filling & Settling: Vacuum-fill with insulating oil, degas, and allow settling before checking oil levels and dielectric strength. |  |
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: Ii6 | 0.00~0.01 | Pass |
| 3 | Polarity tests | / | Additive | Additive | Pass |
| 4 | No-load losses and excitation current | % | I0 :: provide measured value（100%） | 0.41 | Pass |
| kW | P0: provide measured value（100%） | 0.0284 | |||
| % | I0 :: provide measured value（105%） | 0.70 | |||
| kW | P0: provide measured value（105%） | 0.032 | |||
| / | the tolerance for no load loss is +10% | / | |||
| 5 | Load losses , impedance voltage,total losses and efficiency | / | t:85℃ the tolerance for impedance is ±7.5% the tolerance for total load loss is +6% | / | Pass |
| % | Z%: measured value | 2.58 | |||
| kW | Pk: measured value | 0.682 | |||
| kW | Pt: measured value | 0.7104 | |||
| % | Efficiency not less than 98.73% | 99.04 | |||
| 6 | Applied Voltage Test | / | LV: 10kV 60s | No collapse of the test voltage occurs | Pass |
| 7 | Induced Voltage Withstand Test | / | Applied voltage (KV):2 Ur | No collapse of the test voltage occurs | Pass |
| Duration(s):30 | |||||
| Frequency (HZ): 240 | |||||
| 8 | Insulation Resistance Measurement | GΩ | LV-HV to Ground | 94 | Pass |
| HV&LV to Ground | 53.6 | ||||
| 9 | Leakage Test | / | Applied pressure：20kPA | No leakage and no Damage | Pass |
| Duration：12h | |||||
| 10 | Oil Test | kV | Dielectric Strength | 54.9 | Pass |
| mg/kg | Moisture Content | 12.8 | |||
| % | Dissipation Factor | 0.0115 | |||
| mg/kg | Furan Analysis | ≤0.1 | |||
| / | Gas Chromatography Analysis | / |
04 Packing and Shipping
4.1 Packing
 | To ensure safe transportation and storage, the pole-mounted transformer is packed in a custom wooden boxes. The unit is first cleaned and inspected to confirm no oil residues or damage, with protruding parts (e.g., bushings, gauges) wrapped in foam or bubble wrap, and the entire body covered with moisture-resistant paper or plastic film. It is then secured onto a reinforced wooden pallet using straps. The crate, constructed from 15–20mm thick timber, features internal braces to prevent movement, reinforced corners with metal brackets, and an inner waterproof lining. Labels such as “Fragile,” “Keep Dry,” and “This Side Up” are attached, while a packing list, test reports, and manual are sealed in a waterproof bag. During loading, straps and cushioning materials are applied to safeguard against shocks during long-distance transit. |
4.2 Shipping
| Under CIF terms, the pole-mounted transformers will be transported to the port of Montreal. The supplier is responsible for arranging sea freight, covering all costs including insurance and freight charges until the goods arrive at the destination port. The transformers must be securely packed in weatherproof and shock-resistant crates to withstand potential handling impacts and environmental conditions during transit. Proper documentation, such as the bill of lading, commercial invoice, and insurance certificate, will be provided to ensure smooth customs clearance in Montreal. |  |
05 Site And Summary
The pole-mounted transformer is a reliable and efficient solution for decentralized power distribution, designed to withstand harsh environmental conditions while ensuring stable voltage regulation. With robust construction, easy installation, and low maintenance requirements, it is an ideal choice for utility networks, rural electrification, and industrial applications. Backed by stringent quality standards and proven performance, our transformers deliver long-term durability and operational efficiency. Contact us today to find the perfect power distribution solution for your needs.
