333kVA Single Phase Pole Mounted Transformer
NPC ELECTRIC'S 333kVA single phase pole mounted transformer stands as a powerhouse solution for intensive overhead distribution requirements, effectively reducing primary voltages such as 12.47kV, 24.94kV, or 34.5kV to secondary voltages including 120/240V, 277V, or 347V. Crafted with premium grain-oriented silicon steel cores and durable windings, it delivers outstanding energy efficiency, low losses, and compliance with modern DOE efficiency regulations alongside IEEE C57 and ANSI standards. The tank incorporates corrugated fins for optimal natural oil circulation (ONAN), supporting a 65°C temperature rise and robust overload handling. Equipped with essential protections like pressure relief valves, high-voltage bushings, and surge arresters, this transformer ensures dependable operation in exposed conditions. Its design prioritizes quiet performance, minimal maintenance, and extended service life, making it highly suitable for utilities managing substantial single-phase loads in evolving power networks.
- Primary Voltage Ratings 2.4-34.5kV
- Secondary Voltage Ratings 480-240/240-120 or customized
- H.V. Tap Range ± 2×2.5% HV taps or others
- Type Conventional Type
- BIL 30-150kV
- Standards IEEE, ANSI, NEMA, ASTM
- Application Residential, commercial, agricultural and light industrial
- Power Rating 333kVA
- Certificate CE, ISO
- Cooling Method ONAN, KNAN
- Oil Mineral Oil or FR3
- Opeartion Step Down
Technical Specifications
Customization Optional
Packing and Shipping
Manufacturer Test
Routine Testing
Application
Technical Specifications
333kVA Single Phase Pole Mounted Transformer
Technical Specifications
Accessories
| Rated Power | 333kVA |
| Rating Primary Voltage | 12.4-34.5kV |
| Secondary Voltage | 480-240V 240-120V 277V Customized |
| Frequency | 50/60Hz |
| Vector Group | Ii0,Ii6 |
| Winding Material | Aluminum/Copper |
| Efficiency | As IEEE,Doe 2016,CAS Std or Customized |
| Impedance Voltage | Nominal 2% or Customized 1.1-5.75% |
| Altitude | ≤1,000m or Customized |
| Color | ANSI 70 Light gray/Munsell 7GY3.29/1.5 or customized etc |
| Tank material | Mild Steel, 304 Stainless Steel |
| Insulating Oil Weight | 218 kg |
| Total Weight | 980 kg |
| Outline Dimensions（W×D×H） | 915×960×1735 (mm) |
| Lifting Lug |
| Tap Changer |
| Pressure Relief Valve |
| Tank Cover and clamp |
| L.V Bushing |
| HV Bushing |
| Ground Strap |
| Nameplate |
| Non-PCB decal |
| High Voltage Warning Signs |
| Suport lug |
| Oil fill valve |
Customization Optional
333kVA Single Phase Pole Mounted Transformer
Customize the 333kVA single phase pole mounted transformer to perfectly suit your grid's demands with flexible configuration choices that enhance compatibility and efficiency. Primary voltage options cover a broad spectrum from 2.4kV to 34.5kV, including widely used levels like 7.2kV, 13.8kV, 14.4kV, 24.94kV, or dual-voltage setups such as 14.4/27.6kV, paired with secondary outputs like 120/240V, 240/480V, 277V, 347V, or 347/600Y for precise alignment with regional standards. Select aluminum windings for weight savings and economical operation or copper for superior current-carrying capacity and reduced hotspots in intensive use. Frequency options support 50Hz or 60Hz systems, while cooling can upgrade from standard ONAN to include auxiliary fans for high-ambient or overloaded scenarios. Off-circuit tap changers with multiple positions (±2x2.5% or extended ranges) provide on-site voltage fine-tuning, and impedance can be adjusted between 4% and 6% to optimize short-circuit protection. Safety features such as internal expulsion fuses, lightning arresters, wildlife protection, or platform mounting bases address specific environmental risks. For greener operations, choose natural ester or vegetable-based fluids over mineral oil for improved fire safety, enhanced insulation life, and biodegradability. These personalized attributes maximize energy savings, improve fault resilience, and ensure effortless integration into overhead systems, offering utilities and installers a versatile, high-performance transformer tailored to demanding applications.
Further refinements include tank enhancements like reinforced construction for seismic zones, specialized coatings for corrosive atmospheres, or integrated lifting provisions for easier pole installation. Add intelligent monitoring with oil temperature sensors, load tap indicators, or remote diagnostic ports for predictive upkeep. Capacity fine-tuning near 333kVA supports growth projections, and bushing selections up to 150kV BIL accommodate elevated insulation needs. Core optimizations minimize no-load losses, while enclosure modifications reduce acoustic output in sensitive areas. Whether addressing large-scale rural electrification, commercial expansions, or industrial spurs, these extensive customizations deliver the 333kVA single phase pole mounted transformer as a future-ready solution, combining exceptional reliability, regulatory adherence, and cost-effective operation in overhead power distribution.
Packing and Shipping
333kVA Single Phase Pole Mounted Transformer
Packaging for the 333kVA single phase pole mounted transformer employs heavy-duty, export-certified wooden crates with internal steel bracing and strapping to manage substantial weight and dimensions securely. Specialized padding using high-density foam, wooden cradles, and anti-vibration isolators shields sensitive components from transit shocks and vibrations. Moisture protection involves full vacuum bagging, abundant desiccants, and nitrogen purging to maintain oil integrity and prevent oxidation or condensation inside the sealed tank. Bushings and accessories are individually protected and crated separately, with all ports capped and labeled clearly. Comprehensive markings include handling directives, weight distribution, sling points, and international hazard symbols, ensuring safe worldwide transport while preserving the unit's factory condition.
Shipping solutions are optimized for this large-capacity transformer, utilizing specialized heavy-haul trailers with hydraulic suspensions for domestic overland moves, secured with heavy chains, binders, and protective tarpaulins against weather exposure. Overseas transport relies on flat-rack or open-top containers on ocean vessels, with lashing compliant to IMO standards and corrosion preventives for prolonged sea voyages. For time-critical shipments, air freight can be arranged via charter, though ground and sea remain primary due to size. Advanced tracking through satellite and GPS systems, along with all-risk insurance coverage, provides full visibility and financial protection. Compliance with global regulations, including IEC, IEEE, and customs documentation, expedites clearance and reduces potential delays for seamless delivery.
Sustainability drives our packing strategy, incorporating responsibly sourced, recyclable timber and minimizing single-use plastics while consolidating shipments to lower environmental impact. Transit impact recorders monitor forces, enabling verification of handling quality upon receipt. Pre-shipment third-party inspections confirm secure loading and accessory inventories. Our network of vetted carriers, experienced in oversized electrical cargo, adheres to strict safety protocols and permit requirements for road, rail, and port handling.
Delivery support extends to site-specific coordination, including route surveys for challenging access and guidance on unloading with cranes or pole-setting equipment. Detailed manuals outline re-oiling, connection torques, and initial energization steps. This thorough logistics framework guarantees the 333kVA single phase pole mounted transformer reaches destinations intact, ready for rapid installation, and contributes to uninterrupted power reliability in critical infrastructure deployments.
Shipping solutions are optimized for this large-capacity transformer, utilizing specialized heavy-haul trailers with hydraulic suspensions for domestic overland moves, secured with heavy chains, binders, and protective tarpaulins against weather exposure. Overseas transport relies on flat-rack or open-top containers on ocean vessels, with lashing compliant to IMO standards and corrosion preventives for prolonged sea voyages. For time-critical shipments, air freight can be arranged via charter, though ground and sea remain primary due to size. Advanced tracking through satellite and GPS systems, along with all-risk insurance coverage, provides full visibility and financial protection. Compliance with global regulations, including IEC, IEEE, and customs documentation, expedites clearance and reduces potential delays for seamless delivery.
Sustainability drives our packing strategy, incorporating responsibly sourced, recyclable timber and minimizing single-use plastics while consolidating shipments to lower environmental impact. Transit impact recorders monitor forces, enabling verification of handling quality upon receipt. Pre-shipment third-party inspections confirm secure loading and accessory inventories. Our network of vetted carriers, experienced in oversized electrical cargo, adheres to strict safety protocols and permit requirements for road, rail, and port handling.
Delivery support extends to site-specific coordination, including route surveys for challenging access and guidance on unloading with cranes or pole-setting equipment. Detailed manuals outline re-oiling, connection torques, and initial energization steps. This thorough logistics framework guarantees the 333kVA single phase pole mounted transformer reaches destinations intact, ready for rapid installation, and contributes to uninterrupted power reliability in critical infrastructure deployments.
32
32 years of industry experience
Manufacturer Test
333kVA Single Phase Pole Mounted Transformer
Progress Test
As manufacturing progresses for the 333kVA single phase pole mounted transformer, core construction tests involve verifying grain-oriented steel stacking with laser alignment for minimal air gaps and burr removal, followed by epstein frame loss measurements to confirm core losses stay below targeted values. Winding fabrication includes conductor tension monitoring and insulation layer hipot testing at incremental voltages to ensure no weak points. Inter-turn insulation resistance is checked with high-frequency pulses, targeting values over 500 megohms. Preliminary ratio testing uses digital bridges to validate turns accuracy within 0.15% tolerance across taps. Core assembly clamping torque is verified to specification, and vibration response is assessed to simulate field conditions. Oil batch certification checks acidity, breakdown voltage exceeding 40kV, and moisture below 8ppm. Tank weld inspections employ magnetic particle and ultrasonic techniques for defect-free seams, while bracket load tests confirm structural capacity. All interim data feeds into quality dashboards for real-time corrections.
Design Tests
All transformers will be tested after finishing the production, test items as follows:
♦ Insulation Power Factor
♦ Ratio, Polarity, and Phase Relation
♦ Winding Resistance
♦ Impulse Tests
♦ On load Loss Test
♦ No Load Loss Test
♦ Leak Test
♦ DC Insulation Resistance Test
♦ Excitation & No-Load Loss (Rated Voltage)
♦ Applied Voltage
♦ Induced Voltage
♦ Lightning Impulse
♦ Insulation Resistance (Rated Voltage)
♦ Temperature Rise
♦ Dielectric Withstand (Hipot)
Transformer Factory Acceptance Test
Factory acceptance testing for the 333kVA single phase pole mounted transformer begins with full external examination, confirming adherence to dimensional drawings, surface coating quality, nameplate details, and accessory mounting. Winding resistance is precisely measured using micro-ohmmeters with temperature compensation to 80°C, ensuring results within 0.8% of calculated values. Turns ratio and polarity across all taps are validated with high-accuracy TTR instruments, holding errors under 0.2%. Dielectric dissipation factor and capacitance at 12kV confirm tan delta below 0.35%, verifying insulation health. No-load performance testing at rated voltage measures losses and magnetizing current, aligning with DOE efficiency tiers and keeping excitation under 1.2%. Short-circuit impedance and load losses are determined accurately via reduced-voltage method, yielding efficiency figures above 98%. Power frequency withstand applies appropriate kV levels for one minute without issues. Induced overvoltage at elevated frequency stresses insulation integrity. Oil parameters include dielectric strength over 45kV and low gas content via DGA.
Routine Test - Transformer Turns Ratio/TTR
Purpose of Testing
The purpose of the transformer turns ratio (TTR) test is to confirm whether the voltage ratio between each tap of the transformer meets the design requirements and ensure that the transformer winding is connected correctly. By measuring the voltage ratio of each tap, it is possible to detect whether there is a fault or deviation in the transformer winding.
Testing Equipment
TTR tester: such as Doble, Megger, Omicron and other brands of transformer winding ratio tester.
Voltage source: usually AC 10 V to 30 V , used to test different voltages for each tap.
Temperature and humidity meter: used to record environmental conditions during the test to ensure test accuracy.
Current probe: used to measure the load current of the winding and ensure the accuracy of the test results.
Voltage source: usually AC 10 V to 30 V , used to test different voltages for each tap.
Temperature and humidity meter: used to record environmental conditions during the test to ensure test accuracy.
Current probe: used to measure the load current of the winding and ensure the accuracy of the test results.
Pre-Test Preparation
Disconnect all transformer tap-changers from the power supply and ensure that all equipment is properly grounded and discharged.
Perform the test under suitable environmental conditions: relative humidity below 75% and no rain (recommended temperature: 20-30°C). Avoid high humidity or bad weather that may affect the test accuracy.
Perform the test under suitable environmental conditions: relative humidity below 75% and no rain (recommended temperature: 20-30°C). Avoid high humidity or bad weather that may affect the test accuracy.
Test Progress
Perform the test under suitable environmental conditions: relative humidity below 75% and no rain (recommended temperature: 20-30°C). Avoid high humidity or bad weather that may affect the test accuracy.
Measure and Record
Start the test and record the following parameters:
The voltage ratio between the windings
Deviation of the measured value from the rated ratio
The voltage ratio between the windings
Deviation of the measured value from the rated ratio
Temperature Correction
If necessary, perform temperature correction on the measured turns ratio data (especially when testing at higher or lower temperatures). Generally, the standard reference temperature for temperature correction is 20°C.
Repeat Testing (if necessary)
If necessary, perform temperature correction on the measured turns ratio data (especially when testing at higher or lower temperatures). Generally, the standard reference temperature for temperature correction is 20°C.
Evaluation Criteria (Reference)
Turns ratio error ≤ 0.5% (pass)
0.5% < Turns ratio error ≤ 1% (caution)
Turns ratio error > 1% (further inspection or corrective action required)
0.5% < Turns ratio error ≤ 1% (caution)
Turns ratio error > 1% (further inspection or corrective action required)
*These comprehensive tests ensure that each transformer meets performance standards and operates
reliably under various conditions.
Application
Well-suited for dense suburban expansions merged with medium commercial and light industrial demands, this 333kVA single phase pole mounted transformer powers residential subdivisions alongside shopping centers, small factories, municipal services, and EV charging networks, accommodating elevated and variable loads in urban-rural transition zones.
Technical Advantages
● 30+ years of manufacturing experience
● ISO and UL certified production
● Customized cable and transformer solutions
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What is a Transformer?A transformer is an electrical device used to change the voltage of alternating current (AC). It works on the principle of electromagnetic induction, converting high-voltage current into low-voltage current or low-voltage current into high-voltage current. Transformers are widely used in power transmission, distribution systems, and various electronic devices.
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What are the main uses of a transformer?The main use of a transformer is voltage conversion. Transformers are used in power transmission systems to help transfer electricity from power plants to consumers. In addition, transformers are also used in electronic devices such as chargers, televisions, power adapters, etc., to adjust the voltage to meet the requirements of different devices.
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Do you have UL listed?Yes, our transformer has UL listed. We have exported to America many pad mounted transformer,substation transformer and HV.
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