Trusted 75kVA Pole-Mount Transformers - SCOTECH Powering Communities Since 1999
01 General
1.1 Project Description
This 75kVA single-phase pole-mounted transformer was delivered to Guyana in 2024. Rigorously comply with IEEE & ANSI C57.12.00 standards. The polarity is subtractive, and the vector group is Ii0. Rated for a primary voltage of 13,800V and a secondary voltage of 120/240V, making it suitable for residential and small commercial applications.
The power lines transformer features copper windings for enhanced conductivity and efficiency. An impedance of 2%, ensuring minimal voltage drop under load. ±2.5% tapping range, with a total range of 10%. Offers customizable voltage regulation settings, allowing fine‑tuned control to meet specialized power needs.
SCOTECH has over 25 years of experience in transformer manufacturing. Even large orders can be delivered on time with the team’s cooperation.
1.2 Technical Specification
75kVA Single phase pole mounted transformer specification and data sheet
| Delivered to | Guyana |
| Year | 2024 |
| Type | Single phase pole mounted transformer |
| Standard | IEEE & ANSI C57.12.00 |
| Rated Power | 75KVA |
| Frequency | 60HZ |
| Polarity | Subtractive |
| Vector group | Ii0 |
| Primary Voltage | 13800V |
| Secondary Voltage | 120/240V |
| Winding Material | COPPER |
| Impedance | 2% |
| Cooling Method | ONAN |
| Tap Changer | NLTC |
| Tapping Range | ±2X2.5%(Total range=10%) |
| No Load Loss | 214W |
| On Load Loss | 713W |
| Accessories | Standard Configuration |
1.3 Drawings
75kVA Single phase pole mounted transformer dimensions and weight details
02 Manufacturing
2.1 Core
| Wound cores are compact and lightweight, making them ideal for single-phase pole-mounted transformers. Wound cores have fewer joints, and their magnetic flux path aligns with the rolling direction of the magnetic steel sheets, resulting in lower continuous no-load losses. Another advantage of wound cores is that they are quieter than laminated cores. |  |
2.2 Winding
Our transformer windings use high-purity enameled round copper wire, featuring excellent electrical conductivity and compact insulation. Round copper wire is easy to handle and suitable for high-speed automated winding. Adopt an optimized coil structure of foil winding for low-voltage coils and wire winding for high-voltage coils, ensuring excellent operational stability, reliability, and thermal performance.
2.3 Tank
Inside and outside the tank, all welding slag and spatter must be fully removed, with special attention to radiator bases and lifting lugs to avoid dead spots. After sandblasting, the first anti-rust primer must be applied within six hours; beyond that, re-sandblasting is required. Coatings must be applied in two primer coats and two topcoats, with a total thickness of 80 mil, strong adhesion, and a smooth, even, glossy finish.
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
Routine Test
- Resistance Measurements
- Ratio Tests
- Polarity Test
- No Load Losses and No Load Current
- Load Losses and Impedance Voltage
- Applied Voltage Test
- Induced Voltage Withstand Test
- Insulation Resistance Measurement
- Leak Testing with Pressure for Liquid Immersed Transformers
- Oil Dielectric Test
Test Results
| 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 | -0.02 | Pass
|
| 3 | Polarity tests | / | Subtractive | Subtractive | Pass
|
| 4 | No-load losses and excitation current | % kW | I0 :: provide measured value P0: provide measured value the tolerance for no load loss is +10% | 0.49 0.174 | Pass
|
| 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% | 1.98 0.710 0.884 99.11 | 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): 48 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 | 77.3 68.9 64.5 | / |
| 9 | Leakage Test | / | Applied pressure：20kPA Duration：12h | No leakage and no Damage | Pass
|
| 10 | Oil Dielectric Test | kV | ≥45 | 52.00 | Pass
|
04 Packing and Shipping
05 Site and Summary
Reliable and efficient, this 75 kVA transformer power lines was built for Guyana. With high-quality copper windings, durable tank design, and strict quality control, it ensures stable power distribution and long-term performance.
