Three Phase Cast Resin Dry Type Transformer
The Three Phase Cast Resin Dry Type Transformer is a safe, high-efficiency indoor power transformer series designed for reliable medium-voltage to low-voltage step-down in commercial, institutional, industrial, data center, hospital, school, high-rise, and renewable energy applications. With advanced epoxy cast-resin encapsulation and full high-conductivity copper windings, it completely eliminates oil fire risks, environmental hazards, and routine maintenance while offering excellent dielectric strength, thermal performance, resistance to moisture/dust/chemicals, and very low noise levels — making it the ideal choice for fire-sensitive, noise-restricted, space-constrained, or high-reliability indoor installations. Fully compliant with IEC 60076-11, IEC 60076-1/2/3/5/20, EN 50588-1 (eco-design), IEEE C57.12.01, IEEE C57.12.91, UL 1561 (optional listing), and DOE 2016 efficiency standards.
- Primary Voltage Ratings 6.6kV–35kV (customizable: 10kV, 11kV, 13.8kV, 22kV, 33kV, etc.)
- Secondary Voltage Ratings 0.4kV (400/230V), 0.415kV, 0.48kV (480Y/277V) or custom
- H.V. Tap Range ± 2×2.5% HV taps or others
- Type Dry type transformer
- BIL 30/95kV
- Standards IEEE, ANSI, NEMA,IEC,GB
- Application data centers, hospitals, semiconductor facilities
- Power Rating 50-7500kVA
- Certificate IEC 60076-11, IEC 60076-1, IEC 60076-3, UL 1561
- Cooling Method OA/OF
- Opeartion Step Down & Step Up
Technical Specifications
Customization Optional
Packing and Shipping
Manufacturer Test
Routine Testing
Application
Technical Specifications
Three Phase Cast Resin Dry Type Transformer
Technical Specifications
Accessories
| Rated Power | 50kVA - 7500 kVA | |
| Rating Primary Voltage | 6.6kV–35kV | |
| Secondary Voltage | 480/277V 400/230V 380/220V Customized |
|
| Frequency | 50/60Hz | |
| Vector Group | Dyn11,Yyn0,Dyn5 | |
| 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 | |
| Enclosure material | 304 Stainless Steel | |
| HV Bushing |
| LV Bushing |
| Tap changer connector |
| Lifting hook for complete transformer |
| Name plate |
Customization Optional
Three Phase Cast Resin Dry Type Transformer
The three phase cast resin dry type transformer series supports full customization to exactly match medium-voltage grid requirements, low-voltage load needs, installation constraints, acoustic limits, and regional efficiency standards. Primary voltage ranges from 6.6kV to 35kV (common: 6.6kV, 10kV, 11kV, 13.8kV, 20kV, 22kV, 33kV, 35kV) in delta or grounded wye configuration, while secondary voltage can be set to 400/230V, 415/240V, 480Y/277V, 690V, or any custom low-voltage output. Vector groups include Dyn11 (standard), Dyn1, Yyn0, or special configurations for phase shift and harmonic mitigation. Full copper windings are standard for maximum efficiency, lowest hot-spot temperatures, and superior short-circuit strength; aluminum windings are available for cost-sensitive applications.
Insulation system options are Class F (155°C) or Class H (180°C) using advanced cast-resin (epoxy) encapsulation for excellent resistance to moisture, dust, chemicals, and thermal cycling.
Enclosure choices include IP23 ventilated (indoor standard), IP54/IP55 totally enclosed (dust-tight/semi-outdoor), or forced-air cooled (AF) for 133–150% overload capacity in high-ambient or confined spaces. Temperature rise can be specified as 100°C or 120°C. Additional features include forced-air cooling packages with fan controls, digital temperature monitoring with alarm/trip relays, surge arresters, electrostatic shielding for noise-sensitive locations, K-factor rating (K-4 to K-13) for harmonic-rich loads (data centers, EV charging, VFDs), seismic bracing, ultra-low-noise execution (<54 dB with special core clamping and fan design), and custom finishes for corrosive or cleanroom environments. All variants are fully validated to IEC 60076-11, CE marking, local efficiency standards, and client specifications.
Packing and Shipping
Three Phase Cast Resin Dry Type Transformer
The three phase cast resin dry type transformer is packaged with maximum protection to ensure safe domestic and international transport. The core-coil assembly is fully encapsulated in cast resin and rigidly secured inside the enclosure to prevent movement during transit. All terminals, taps, temperature sensors, fans (if equipped), and accessories are factory-installed and protected with caps or padding to avoid damage to bushings and connections.
The transformer is mounted on a reinforced wooden pallet or steel skid designed for forklift and crane handling, wrapped in multi-layer stretch film and moisture-barrier material. Desiccant packs are included to control humidity, critical for cast-resin units that must remain dry before energization. The entire unit is then placed in a sturdy export-grade wooden crate (ISPM-15 heat-treated) with foam corner protectors, wooden bracing, and steel strapping for stability. Clear markings include gross/net weight, center of gravity, lift points, dimensions (approx. 2.0–3.5 m L × 1.4–2.5 m W × 2.0–3.0 m H depending on rating), and handling instructions (“Fragile – Electrical Equipment – No Tipping”).
Domestic shipping uses enclosed trailers or flatbeds with secure blocking and tie-downs to minimize vibration. International shipments typically utilize 20ft/40ft containers (palletized and shrink-wrapped) or flat-rack loading, with professional lashing using chains and timber dunnage for sea and road stability. Real-time GPS tracking and full-value cargo insurance are standard for high-value units. Upon arrival, detailed handling and installation manuals are provided, covering lifting procedures (via integrated lifting eyes), foundation placement with ventilation clearances, electrical connections, grounding, and pre-energization checks (insulation resistance, turns ratio, temperature sensor calibration).
Comprehensive export documentation—including commercial invoices, detailed dimensional/weight manifests, origin certificates, test reports, and IEC compliance declarations—is prepared in advance for rapid customs clearance. Sustainable logistics practices incorporate reusable skids, optimized container loading, and carbon-offset options where available. Clients benefit from secure tracking portals with real-time satellite positioning, ETA forecasts, and dedicated logistics support.
Post-arrival services include optional heavy-lift crane/SPMT offloading coordination, immediate condition assessment, insulation verification, and packaging recycling/disposal to accelerate commissioning. Multi-unit orders leverage consolidated shipments and phased delivery scheduling. This professional end-to-end logistics ensures the transformer arrives pristine and installation-ready.
The transformer is mounted on a reinforced wooden pallet or steel skid designed for forklift and crane handling, wrapped in multi-layer stretch film and moisture-barrier material. Desiccant packs are included to control humidity, critical for cast-resin units that must remain dry before energization. The entire unit is then placed in a sturdy export-grade wooden crate (ISPM-15 heat-treated) with foam corner protectors, wooden bracing, and steel strapping for stability. Clear markings include gross/net weight, center of gravity, lift points, dimensions (approx. 2.0–3.5 m L × 1.4–2.5 m W × 2.0–3.0 m H depending on rating), and handling instructions (“Fragile – Electrical Equipment – No Tipping”).
Domestic shipping uses enclosed trailers or flatbeds with secure blocking and tie-downs to minimize vibration. International shipments typically utilize 20ft/40ft containers (palletized and shrink-wrapped) or flat-rack loading, with professional lashing using chains and timber dunnage for sea and road stability. Real-time GPS tracking and full-value cargo insurance are standard for high-value units. Upon arrival, detailed handling and installation manuals are provided, covering lifting procedures (via integrated lifting eyes), foundation placement with ventilation clearances, electrical connections, grounding, and pre-energization checks (insulation resistance, turns ratio, temperature sensor calibration).
Comprehensive export documentation—including commercial invoices, detailed dimensional/weight manifests, origin certificates, test reports, and IEC compliance declarations—is prepared in advance for rapid customs clearance. Sustainable logistics practices incorporate reusable skids, optimized container loading, and carbon-offset options where available. Clients benefit from secure tracking portals with real-time satellite positioning, ETA forecasts, and dedicated logistics support.
Post-arrival services include optional heavy-lift crane/SPMT offloading coordination, immediate condition assessment, insulation verification, and packaging recycling/disposal to accelerate commissioning. Multi-unit orders leverage consolidated shipments and phased delivery scheduling. This professional end-to-end logistics ensures the transformer arrives pristine and installation-ready.
32
32 years of industry experience
Manufacturer Test
Three Phase Cast Resin Dry Type Transformer
Progress Test
Early manufacturing stages for three-phase cast resin dry type transformers include core validation through Epstein frame, watt-loss, and flux density testing on premium grain-oriented silicon steel to guarantee ultra-low no-load losses. Copper (or aluminum) winding production employs precision automated layering with continuous inter-turn high-potential surge testing for insulation uniformity. Pre-casting conductor and spacer alignment is verified via 3D laser scanning for accurate duct placement. Vacuum pressure impregnation cycles are monitored with real-time resin flow sensors and ultrasonic void detection. Core-coil preliminary assembly includes low-voltage excitation for magnetization curve, harmonic content, and magnetic balance profiling. These systematic validations, supported by fully serialized digital traceability, establish the foundation for high-efficiency performance. Advanced progress evaluations feature resin casting with multi-zone temperature-controlled curing, post-cure hardness testing, and thermal expansion verification. Partial discharge pre-screening during stepped voltage ramps confirms levels well below acceptance thresholds.
Design Tests
All transformer will be test after finished the production, test items as below:
♦ Insulation Power Factor
♦ 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)
♦ Excitation & No-Load Loss (Rated Voltage)
♦ Applied Voltage
♦ Insulation Resistance (Rated Voltage)
♦ Temperature Rise
Transformer Factory Acceptance Test
Sophisticated FAT continuation incorporates double-frequency induced overvoltage with ultra-sensitive partial discharge, RIV, and acoustic emission monitoring, maintaining discharge well below 10 pC across the entire voltage envelope. Temperature rise testing at rated and overload conditions employs distributed fiber-optic sensors to verify hotspot temperatures remain within Class F/H limits. Regulation, impedance, and full-load loss are precisely quantified using calibrated short-circuit methods. Operational cycling of tap changers (if fitted) and accessory functionality (relays, fans) is demonstrated extensively. Acoustic performance is characterized via sound intensity mapping in a hemi-anechoic environment, confirming low-noise compliance. Final holistic inspection verifies resin surface quality, terminal accessibility, enclosure protection, finish durability, and labeling accuracy. Complete test documentation—including thermal imaging, waveform archives, signed reports, and traceability certificates—accompanies the transformer, fully endorsing its readiness for reliable indoor power distribution.
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)
nsulation 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
Test standard
IEEE C57.12.01 & IEEE C57.12.91 (Dry-Type)
*These comprehensive tests ensure that each transformer meets performance standards and operates
reliably under various conditions.
Application
Predominantly used in mixed-use developments, light-to-medium industrial plants, indoor substations, and critical infrastructure projects, offering energy-efficient, fire-safe three-phase power distribution for integrated commercial, institutional, industrial, and utility operations.
Technical Advantages
● 30+ years of manufacturing experience
● ISO and UL certified production
● Customized cable and transformer solutions
Product Packaging
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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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