333kVA Single Phase Pad Mounted Transformer
The 333kVA Single Phase Pad Mounted Transformer is a high-performance electrical transformer designed for reliable power distribution in industrial and commercial applications. With a robust, weather-resistant enclosure, it is ideal for outdoor installations and offers efficient step-down voltage conversion. This transformer features a 333kVA capacity, providing reliable power to meet the demands of single-phase systems, and comes with customizable primary and secondary voltage configurations.
- Primary Voltage Ratings 34.5-19.92/13.8-7.957/13.2-7.62/12.47-7.2, 24.94, 26.25, 33 or others
- Secondary Voltage Ratings 480-240/240-120or customized
- H.V. Tap Range ± 2×2.5% HV taps or others
- Type Loop Feed or Radial Feed
- BIL 30/95kV
- Standards IEEE, ANSI
- Application Power Distribution,Renewable Energy Systems
- Power Rating 333kVA
- Certificate UL/cUL, CSA, CESI
- Cooling Method ONAN, ONAN/ONAF, KNAN, KNAN/KNAF
- Oil Mineral Oil or FR3
- Opeartion Step Down & Step Up
Technical Specifications
Customization Optional
Packing and Shipping
Manufacturer Test
Routine Testing
Application
Technical Specifications
333kVA Single Phase Pad Mounted Transformer
Technical Specifications
Accessories
| Rated Power | 333 kVA |
| Rating Primary Voltage | 11950Delta or Customized |
| 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 | 400 kg |
| Total Weight | 2000 kg |
| Outline Dimensions（L×W×H）in. | 1300×1100×1400(mm) |
| Lifting Lug | ELSP Fuse |
| Hinged Door | BAY-O-NET Fuse |
| Parking Bracket | Tap Changer |
| Tank Cover | Oil Level Gauge |
| L.V Bushing (4-Hole ) | Pressure Relief Valve |
| Two/Four Position Load break Switch | Vacuum Pressure Gauge |
| HV Grounding Copper Bar | Terminal Block |
| Temperature Indicator | Door Handle |
| H.V Bushing Well | Ground Strap |
| Grounding Copper Bar | Nameplate |
| 1"'Drain Valve With 3/8" Sampler | Non-PCB decal |
| 1" Upper Fill Valve Filter Press Connection | High Voltage Warning Signs |
Customization Optional
333kVA Single Phase Pad Mounted Transformer
NPC ELECTRIC’s single-phase pad-mounted transformers can be fully customized to meet your specific requirements.
For 333kVA single-phase pad-mounted transformers, the optional specifications are rich and varied. In terms of voltage, the primary input voltage can be selected from common specifications such as 11kV and 22kV according to different grid requirements, and the secondary output voltage is also available in a variety of standards such as 400V and 480V. The tap range can be set to ±2×2.5% or ±5% to flexibly cope with voltage fluctuations. The insulation level can be selected from F or H, which can withstand higher temperatures and improve the stability and reliability of operation. The protection level can be selected from IP33, IP44, etc. to meet the protection requirements of different outdoor environments and prevent the intrusion of foreign matter and water. In addition to the common natural air cooling (ONAN), the cooling method can also be selected with forced air cooling (OFAF) to enhance the heat dissipation capacity and cope with higher load requirements.You can also choose to install an intelligent monitoring system to monitor the transformer's temperature, winding temperature, oil level and other operating parameters in real time, and realize remote communication and monitoring functions to facilitate operation and maintenance management.
Packing and Shipping
333kVA Single Phase Pad Mounted Transformer
Each 333kVA single phase pad mounted transformer is rigorously prepared for safe worldwide delivery, starting with comprehensive pre-packing inspections that include oil dielectric testing (if shipped filled), nitrogen purging for dry shipments to eliminate moisture and oxygen, and secure wrapping of bushings, gauges, and fittings with foam or rigid covers to withstand transit stresses. The tank exterior receives protective coatings, temporary rust inhibitors, and impact shielding on vulnerable areas like bushings and valves. All loose accessories are individually packaged, labeled, and braced inside the crate to prevent movement.
Packing employs reinforced wooden crates or skids built to exact dimensions, reinforced with steel strapping, internal supports, and blocking to distribute the unit's weight (typically 2800-3500 lbs dry, more when oil-filled). For export, crates meet ISPM 15 phytosanitary standards via heat treatment, with added vapor barrier films, silica gel desiccants, and humidity indicators. Oil-filled shipments incorporate sealed gaskets, absorbent padding around fittings, and compliance with hazardous materials regulations (UN 3082 for insulating oils), including proper labeling and documentation. Domestic packaging may use simpler palletized setups with stretch wrap for truck transport.
Shipping solutions are selected for reliability and speed, with domestic North American deliveries via specialized heavy-haul carriers using lowboy trailers, secure chain tie-downs, and escort services when required for oversize loads. International orders utilize multimodal logistics: truck to port, ocean freight in 40ft open-top or flat-rack containers (or break-bulk for multiple units), followed by destination trucking.
At delivery, inspect for shipping damage, verify seals, oil levels, and accessories immediately. Professional rigging with spreader bars is recommended for safe offloading to avoid tank distortion. Our dedicated logistics support includes freight coordination, customs paperwork preparation (commercial invoices, certificates of origin, test reports), and export compliance to streamline clearance and minimize delays, ensuring the transformer arrives site-ready for concrete pad placement, cable connections, and energization.
Packing employs reinforced wooden crates or skids built to exact dimensions, reinforced with steel strapping, internal supports, and blocking to distribute the unit's weight (typically 2800-3500 lbs dry, more when oil-filled). For export, crates meet ISPM 15 phytosanitary standards via heat treatment, with added vapor barrier films, silica gel desiccants, and humidity indicators. Oil-filled shipments incorporate sealed gaskets, absorbent padding around fittings, and compliance with hazardous materials regulations (UN 3082 for insulating oils), including proper labeling and documentation. Domestic packaging may use simpler palletized setups with stretch wrap for truck transport.
Shipping solutions are selected for reliability and speed, with domestic North American deliveries via specialized heavy-haul carriers using lowboy trailers, secure chain tie-downs, and escort services when required for oversize loads. International orders utilize multimodal logistics: truck to port, ocean freight in 40ft open-top or flat-rack containers (or break-bulk for multiple units), followed by destination trucking.
At delivery, inspect for shipping damage, verify seals, oil levels, and accessories immediately. Professional rigging with spreader bars is recommended for safe offloading to avoid tank distortion. Our dedicated logistics support includes freight coordination, customs paperwork preparation (commercial invoices, certificates of origin, test reports), and export compliance to streamline clearance and minimize delays, ensuring the transformer arrives site-ready for concrete pad placement, cable connections, and energization.
32
32 years of industry experience
Manufacturer Test
333kVA Single Phase Pad Mounted Transformer
Progress Test
Throughout fabrication of the 333kVA single phase pad mounted transformer, progress tests monitor quality at critical milestones. Core assembly checks include lamination stacking accuracy, clamping pressure verification, and interlaminar insulation resistance to minimize eddy current losses. Winding production involves conductor insulation testing, precise layering, and turn counting with continuity scans for defect-free coils. Post-winding core-coil integration features preliminary hipot insulation checks, core grounding confirmation, and dimensional inspections against tolerances. Tank manufacturing progress includes weld seam dye penetrant or magnetic particle testing, hydrostatic pressure testing for leaks, shot-blasting for surface prep, and primer application thickness measurement. Assembly stages cover bushing torque verification, accessory alignment, gasket compression tests, and initial fluid processing oversight to ensure contamination-free environment.
Design Tests
All transformer will be test after finished the production, test items as below:
♦ 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
♦ Transformer Turns Ratio/TTR (All Tap Voltages)
♦ Impedance Voltage & Load Loss (Rated Voltage)
♦ Polarity, 1-Ph / Phase Relation, 3-Ph (Rated Voltage)
♦ Excitation & No-Load Loss (Rated Voltage)
♦ Applied Voltage
♦ Insulation Resistance (Rated Voltage)
♦ Temperature Rise
♦ Dielectric Withstand (Hipot)
Transformer Factory Acceptance Test
Dielectric withstand includes applied potential (separate source) and induced voltage tests at elevated levels without flashover or partial discharge. Impedance voltage and load loss are determined under short-circuit conditions, comparing to guaranteed values. Oil quality tests (breakdown voltage, acidity, moisture) apply if shipped filled. Functional operations verify fuses, pressure relief activation, gauges, valves, and bushing integrity. Optional tests like sound power level, temperature rise simulation, or special impulse may be included per specification. Results are compiled in detailed reports, witnessed if requested, and certified compliant with IEEE C57.12.00, C57.12.38, ANSI, and efficiency standards before release for shipment, confirming field-ready reliability and performance. DC winding resistance is measured and temperature-corrected. No-load loss, excitation current, and core noise levels are recorded at rated voltage to validate efficiency and quiet operation per DOE 2016.
Routine Test - Applied Voltage
Purpose of Testing
The purpose of testing the applied voltage is to verify the insulation strength of the transformer by applying a voltage higher than its normal operating level, ensuring it can withstand potential electrical stresses. This test helps identify any weaknesses or defects in the insulation system before the transformer is put into service.
Testing Equipment
Test equipment: High voltage tester (e.g. TTR, Hipot, etc.)
Voltage source: usually 1 kV, 5 kV, 10 kV, or customized according to customer needs
Temperature and humidity meter: used to record environmental conditions
Voltage source: usually 1 kV, 5 kV, 10 kV, or customized according to customer needs
Temperature and humidity meter: used to record environmental conditions
Pre-Test Preparation
Disconnect the device from the power supply and make sure it is properly grounded and discharged.
Check the connection terminals and wiring to ensure that they are not loose or contaminated.
Test under suitable environmental conditions: relative humidity below 75% and no rain (recommended temperature: 20-30°C).
Check the connection terminals and wiring to ensure that they are not loose or contaminated.
Test under suitable environmental conditions: relative humidity below 75% and no rain (recommended temperature: 20-30°C).
Test Progress
Connect the Test Instrument:
Properly connect the test equipment to the bushings or terminals of the device under test and ensure that all connection points are properly grounded.
Selecting the test voltage:
Select the appropriate applied voltage based on the rated voltage of the equipment.
Properly connect the test equipment to the bushings or terminals of the device under test and ensure that all connection points are properly grounded.
Selecting the test voltage:
Select the appropriate applied voltage based on the rated voltage of the equipment.
Measure and Record
Start the test and record the following parameters:
Measuring leakage current
Applied voltage
Current stability
Any possible voltage fluctuations
Measuring leakage current
Applied voltage
Current stability
Any possible voltage fluctuations
Temperature Correction
If necessary, the measured data is temperature corrected to ensure that it corresponds to standard temperature conditions (usually 20°C).
Repeat Testing (if necessary)
Multiple tests were conducted on different windings (high voltage, medium voltage, low voltage) and bushings, and comparative analysis was performed.
Evaluation Criteria (Reference)
The test was normal and the equipment performed well (qualified)
The current value exceeded the allowable range and the equipment needs to be inspected or maintained (pending repair)
There was a serious fault or instability and the equipment could not continue to operate (unqualified)
The current value exceeded the allowable range and the equipment needs to be inspected or maintained (pending repair)
There was a serious fault or instability and the equipment could not continue to operate (unqualified)
Observing electrical behavior
Observe the electrical behavior of the device under test to ensure that there are no abnormal currents, arcing, noise, or electrical faults.
*These comprehensive tests ensure that each transformer meets performance standards and operates
reliably under various conditions.
Application
Excellent for light commercial districts, office parks, schools, medical clinics, and transportation facilities like bus depots or small airports requiring robust, tamper-resistant power supply; integrates well with industrial sites, renewable solar installations, EV charging infrastructure, and utility network upgrades demanding high-capacity, efficient single-phase underground delivery in urban or mixed-use environments.
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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