25kVA Single Phase Pad Mounted transformer
- 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, CSA, NEMA, DOE
- Application ultilities, residential, single family house, commercial district etc
- Power Rating 25kVA
- Certificate UL/cUL ,CESI , CSA
- Cooling Method ONAN, ONAN/ONAF, KNAN, KNAN/KNAF
- Oil Minerial Oil or FR3
- Opeartion Step Down & Step Up
Technical Specifications
Rated Power | 25 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 | 135 kg |
Total Weight | 360 kg |
Outline Dimensions(L×W×H)in. | 1000×900×700(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
Packing and Shipping


Manufacturer Test

Progress Test
NPC Electirc manufacture pad mounted transformer have the strict quality control. The Progress Test for a 25kVA Single Phase Pad Mounted Transformer is conducted at various stages during the manufacturing process to ensure the transformer meets all technical specifications and quality standards. This includes testing of key components such as the core insulation, winding resistance, and dielectric strength. The transformer’s electrical components, such as bushings and tap changers, are also tested for proper functionality.
The progress tests assess the transformer’s ability to handle operational conditions, including load variations and voltage fluctuations, ensuring it performs efficiently and safely. Any issues identified during these tests are addressed promptly, ensuring that the transformer is fully optimized and ready for the final Factory Acceptance Test (FAT).
The progress test guarantees that the 25kVA Single Phase Pad Mounted Transformer is built to the highest standards of reliability and safety before final delivery.

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
♦ Induced Voltage
♦ Lightning Impulse
♦ Insulation Resistance (Rated Voltage)
♦ Temperature Rise
♦ Dielectric Withstand (Hipot)

Transformer Factory Acceptance Test
NPC Electric will tests made for quality control by the manufacturer on every device or representative samples, or on parts or materials as required, to verify during production that the product meets the design specifications.
The Transformer Factory Acceptance Test (FAT) for a 25kVA Single Phase Pad Mounted Transformer is a crucial procedure conducted to verify that the transformer meets all required specifications and industry standards before it is shipped to the customer. The FAT typically includes the following key tests: Visual and Mechanical Inspection: Ensuring proper assembly, verifying that all components are correctly installed, and checking for any physical defects or damage. Electrical Testing: This involves measuring winding resistance, insulation resistance, and conducting a turns ratio test to confirm the electrical integrity of the transformer. Dielectric Testing: Applying high voltage to test the transformer’s insulation system to ensure it can withstand normal operating and transient voltages. Load and Performance Testing: Simulating operational conditions to assess the transformer’s performance under load, including checking voltage regulation and efficiency. Safety and Protection Feature Testing: Verifying the functionality of protective devices such as surge arresters, pressure relief valves, and tap changers to ensure safe operation under fault conditions. The FAT ensures that the 25kVA Single Phase Pad Mounted Transformer is fully functional, safe, and ready for reliable operation, providing peace of mind for the customer upon delivery.
Routine Test - On load Loss Test:
Voltage source and current source (usually rated voltage, or adjusted according to the test standard, such as 10 KV, 20 KV, 35 KV, etc.)
Temperature and humidity meter (used to record ambient temperature and humidity for correction of test data)
The test environment should be dry and rainless, with a relative humidity of less than 75% and a recommended temperature range of 20–30°C.
Connect the test equipment to the appropriate terminals of the device under test and ensure that all wiring is correct and the device is well grounded.
Apply Test Voltage:
Apply the specified test voltage at the rated frequency and adjust the low voltage side to maintain the rated current (or specified current).
On-Load Loss Power
Input Power and Output Power
Current
Voltage
Temperature (temperature rise or winding temperature)
Ambient temperature and humidity during the test

Application
Technical Advantages
Product Packaging
Related Products
FAQ From Customers
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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.