75kVA Single Phase Pad Mounted transformer
The 75kVA single phase pad mounted transformer is designed for medium-capacity underground residential and light commercial distribution, transforming primary voltages such as 12470GrdY/7200, 24940GrdY/14400, 34500GrdY/19920, or dual-voltage setups to secondary 120/240V split-phase or 240V. The compartmental dead-front enclosure with tamper-resistant doors, mineral oil insulation, and ONAN cooling supports a 65°C temperature rise for dependable performance under residential peak demands.
- 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 CSA, IEEE, DOE, NEMA
- Application Utilities, Hospitals, shopping malls, single-family villas
- Power Rating 75kVA
- 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
75kVA Single Phase Pad Mounted transformer
Technical Specifications
Accessories
| Rated Power | 75 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 | 205 kg |
| Total Weight | 650 kg |
| Outline Dimensions（L×W×H）in. | 1100×900×710(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
75kVA Single Phase Pad Mounted transformer
NPC ELECTRIC’s single-phase pad-mounted transformers can be fully customized to meet your specific requirements.
The 75kVA Single Phase Pad Mounted Transformer offers a range of optional specifications to meet specific operational, safety, and environmental needs. These options include the selection of insulating oil types, such as traditional mineral oil or environmentally friendly biodegradable oil, to meet environmental regulations and enhance safety. For improved voltage regulation under varying load conditions, an on-load tap changer (OLTC) can be added. The transformer can also be equipped with temperature monitoring systems to provide real-time temperature data and ensure safe operation. Additional protection devices like surge arresters, fault indicators, and pressure relief valves can be incorporated for enhanced safety and reliability. To ensure the transformer’s durability in challenging conditions, corrosion-resistant coatings or weatherproof enclosures are available. These customizable options allow the 75kVA Single Phase Pad Mounted Transformer to be tailored to specific site conditions and operational requirements, ensuring optimal performance and longevity.
Packing and Shipping
75kVA Single Phase Pad Mounted transformer
Packaging for the 75kVA single phase pad mounted transformer utilizes export-grade wooden crates reinforced with steel strapping and internal timber bracing to secure the compartmental tank and prevent movement. High-density foam padding, vibration-absorbing mounts, and corner guards protect bushings, doors, and fittings from transit shocks, while vacuum sealing, desiccant packets, and nitrogen pressurization safeguard insulating oil against moisture and oxidation. HV/LV compartments are individually shielded, ports tightly capped, and partial oil drainage complies with safety regulations. Detailed international labels specify handling instructions, weight distribution, sling points, and hazard classifications for secure global shipment.
Shipping arrangements accommodate the transformer's weight, employing specialized lowboy trailers with heavy-duty chains and full weatherproof tarps for domestic overland transport to shield from environmental factors. International consignments use flat-rack or open-top containers on ocean vessels with IMO-compliant lashing and corrosion preventives for marine exposure. Continuous GPS satellite tracking and comprehensive cargo insurance ensure real-time visibility and protection. Full alignment with ANSI, IEEE, and customs requirements accelerates processing, minimizing delays for the 75kVA single phase pad mounted transformer in worldwide utility projects.
Sustainability shapes packing choices, incorporating responsibly sourced recyclable timber and optimized configurations to reduce emissions. Impact and tilt recorders on crates document handling conditions for post-arrival verification and claim resolution. Accessories like arresters, fuses, or gauges ship separately with itemized checklists for onsite reconciliation. Proven carriers specializing in pad-mounted equipment secure heavy-haul permits and prioritize safety across diverse land and sea routes.
Upon arrival, detailed support provides pad site preparation guidance, step-by-step unpacking protocols, oil refilling steps, and connection torque specifications. Coordination with installers ensures efficient handling and rapid commissioning. This thorough logistics process safeguards transformer integrity, expedites deployment, and supports uninterrupted underground residential power reliability.
Shipping arrangements accommodate the transformer's weight, employing specialized lowboy trailers with heavy-duty chains and full weatherproof tarps for domestic overland transport to shield from environmental factors. International consignments use flat-rack or open-top containers on ocean vessels with IMO-compliant lashing and corrosion preventives for marine exposure. Continuous GPS satellite tracking and comprehensive cargo insurance ensure real-time visibility and protection. Full alignment with ANSI, IEEE, and customs requirements accelerates processing, minimizing delays for the 75kVA single phase pad mounted transformer in worldwide utility projects.
Sustainability shapes packing choices, incorporating responsibly sourced recyclable timber and optimized configurations to reduce emissions. Impact and tilt recorders on crates document handling conditions for post-arrival verification and claim resolution. Accessories like arresters, fuses, or gauges ship separately with itemized checklists for onsite reconciliation. Proven carriers specializing in pad-mounted equipment secure heavy-haul permits and prioritize safety across diverse land and sea routes.
Upon arrival, detailed support provides pad site preparation guidance, step-by-step unpacking protocols, oil refilling steps, and connection torque specifications. Coordination with installers ensures efficient handling and rapid commissioning. This thorough logistics process safeguards transformer integrity, expedites deployment, and supports uninterrupted underground residential power reliability.
32
32 years of industry experience
Manufacturer Test
75kVA Single Phase Pad Mounted transformer
Progress Test
NPC Electirc manufacture pad mounted transformer have the strict quality control. The Progress Test for a 75kVA Single Phase Pad Mounted Transformer is conducted throughout the manufacturing process to ensure that the transformer meets all design, quality, and performance standards. This includes verifying the integrity of the core insulation and winding resistance, as well as checking the dielectric strength to ensure the transformer can safely handle electrical stress. Electrical tests, such as insulation resistance and turns ratio tests, are performed to confirm proper functionality. Additionally, the transformer’s protection devices, including bushings, surge arresters, and tap changers, are tested to ensure they operate correctly. The progress test also includes simulated load conditions to assess the transformer’s performance and efficiency. Any issues identified during the progress test are addressed before the transformer moves on to the final Factory Acceptance Test (FAT), ensuring that the 75kVA Single Phase Pad Mounted Transformer meets high-quality standards and is ready for reliable operation. Protective coordination simulates fault timing. Progress reports conform to ANSI/IEEE C57.12.34 and DOE standards, enabling refinements before final oil impregnation and enclosure sealing.
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
♦ 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
Factory acceptance testing for the 75kVA single phase pad mounted transformer initiates with visual and dimensional audits per drawings, evaluating enclosure construction, dead-front security, bushing alignment, and compartment integrity. Winding DC resistance uses Kelvin bridge techniques with temperature correction, results within 0.8% tolerance. Turns ratio and polarity validation across taps employs high-precision TTR for errors below 0.3%. Dissipation factor and capacitance at 10kV limit tan delta below 0.45%. No-load loss and exciting current at rated voltage confirm DOE efficiency compliance, excitation limited appropriately. Load loss and impedance quantification via short-circuit method yields accurate performance metrics. Power frequency withstand applies required kV for one minute without flashover. Induced voltage test stresses inter-turn insulation. Oil analysis confirms breakdown voltage exceeding 40kV and minimal dissolved gases. Acoustic measurements in controlled settings ensure noise compliance. Temperature rise testing under equivalent loading restricts top-oil and winding rises to 65°C. Accessory operations verify pressure relief response, liquid gauges, tap changer function, and parking stands. Sweep frequency response analysis confirms core/winding mechanical stability. All test results compile per ANSI C57.12.34, IEEE C57.12.90, and DOE standards with calibration traceability, client witnessing, and prompt resolution of non-conformances prior to final acceptance and shipment preparation.
Routine Test - DC Insulation Resistance Test
Purpose of Testing
The purpose of DC insulation resistance testing is to measure the insulation resistance of a device by applying a DC voltage, thereby evaluating the health of the insulation material and the voltage withstand capability of the electrical device. This test helps detect potential insulation aging, moisture or damage, preventing electrical failures in the device.
Testing Equipment
Insulation resistance tester (e.g. Megger, Fluke, Hioki, Klein Tools, etc.)
Voltage source (usually 500V, 1000V, 2500V, or customized according to customer requirements)
Temperature and humidity meter (used to record the ambient temperature and humidity during the test to ensure that the test conditions meet the standard requirements.)
Voltage source (usually 500V, 1000V, 2500V, or customized according to customer requirements)
Temperature and humidity meter (used to record the ambient temperature and humidity during the test to ensure that the test conditions meet the standard requirements.)
Pre-Test Preparation
Make sure the device is properly grounded and fully discharged to prevent residual charge in the device from affecting the test results.
Perform the test under suitable environmental conditions. It is recommended to have a relative humidity below 75%, no rain, and a temperature range of 20-30°C to avoid moisture or temperature fluctuations affecting the test results.
Perform the test under suitable environmental conditions. It is recommended to have a relative humidity below 75%, no rain, and a temperature range of 20-30°C to avoid moisture or temperature fluctuations affecting the test results.
Test Progress
Connect the Test Instrument:
Connect an insulation resistance tester to the high voltage terminal of the device under test and to ground.
Apply Test Voltage:
Select an appropriate test voltage based on the rated voltage of the equipment .
Connect an insulation resistance tester to the high voltage terminal of the device under test and to ground.
Apply Test Voltage:
Select an appropriate test voltage based on the rated voltage of the equipment .
Measure and Record
Start the test and record the following parameters:
Insulation resistance value (MΩ)
Applied voltage
Ambient temperature and humidity during testing
Insulation resistance value (MΩ)
Applied voltage
Ambient temperature and humidity during testing
Temperature Correction
The measured insulation resistance values are corrected to a reference temperature (usually 20°C) for accurate evaluation.
Repeat Testing (if necessary)
Measure different windings (high voltage, medium voltage, low voltage) or each bushing separately, and conduct comparative analysis to ensure the insulation status of all parts.
Evaluation Criteria (Reference)
Insulation resistance ≥ 1000 MΩ (excellent)
500 MΩ ≤ Insulation resistance < 1000 MΩ (good)
100 MΩ ≤ Insulation resistance < 500 MΩ
Insulation resistance < 100 MΩ
500 MΩ ≤ Insulation resistance < 1000 MΩ (good)
100 MΩ ≤ Insulation resistance < 500 MΩ
Insulation resistance < 100 MΩ
*These comprehensive tests ensure that each transformer meets performance standards and operates
reliably under various conditions.
Application
The 75kVA single phase pad mounted transformer excels in expanding suburban residential underground networks combined with multi-home developments, stepping down medium voltage to 120/240V for powering houses, appliances, HVAC, and community lighting with tamper-resistant pad installation in family neighborhoods.
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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