Primary Voltage: 480V
Secondary Voltage: 120V
Power Rating: customize
Connection Type: Dyn11 (Delta-Primary, Wye-Secondary with neutral), or other configurations
Transformer Type: Dry Type Transformer
Standards: ANSI/IEEE, CSA/CAN, DOE
Certificates: UL, cUL, CSA, SGS, CE
This transformer adopts air insulation and air cooling with oil-free design, completely eliminating fire risks and dielectric leakage hazards. Featuring flame retardant, explosion-proof performance and low operating loss, it is equipped with an intelligent temperature control system and can be directly installed at load centers, making it the optimal solution for modern urban power grids and industrial power distribution. CHBEB Group Co., Ltd. is a professional transformer manufacturer and high-quality producer of dry-type transformers. The rated parameters of dry-type isolation transformers are listed below:
Standard Tap Changer
±2×2.5% off-circuit voltage regulation
· 380V: For aging power grids in Africa
· 400V: For the Middle East and mainstream African markets
· 480V: For industrial power grids in the United States
Connection Group
Dyn11 or Dy1
· Dyn11: For Middle East and Africa (IEC system)
· Dy1: Compliant with ANSI phase standards for the US market
Frequency
50Hz or 60Hz
· 50Hz: Municipal power grids in the Middle East and Africa
· 60Hz: United States and overseas self-contained generator sets
Short-Circuit Impedance
4%, 5.75% or 6%
· 4%: Conventional power distribution for the Middle East and Africa
· 5.75%/6%: For the US and oilfield working conditions with high short-circuit risks
No-load Loss
≤480W (50Hz) or customized per DOE standards (60Hz)
· Original loss values apply to 50Hz models; loss values shall be recalculated and retested to meet DOE energy efficiency standards for US shipments
Load Loss
≤1700W (120℃, 50Hz) or corresponding values specified by DOE (60Hz)
· Original parameters apply to 50Hz models; load loss recalculated for 60Hz US orders
Power Frequency Withstand Voltage
3kV/1min, 4kV/1min or UL specified withstand voltage levels
· 3kV basic version: For general African projects
· 4kV: For high-standard clients in the Middle East
· UL exclusive withstand voltage: For US certified models
Insulation Class
Class F or Class H
· Class F: Conventional indoor environments
· Class H: Harsh high-temperature and dusty environments in the Middle East
Cooling Mode
AN/AF
· Dual modes of natural air cooling and forced air cooling, applicable to all markets
The iron core is processed with high-quality grain-oriented silicon steel, and the yoke end faces are coated with special resin adhesive, delivering low loss, low noise and stable performance.
The interlayer of low-voltage coils is wound with pre-impregnated DMD material and cured at high temperature, providing excellent insulation performance and high overall mechanical strength.
The high-voltage coil adopts a segmented multi-layer cylindrical structure with longitudinal air channels, manufactured via vacuum pressure casting. It boasts high mechanical strength, strong short-circuit resistance, low partial discharge, and superior resistance to moisture, dust and salt spray.
The overall structure is concise, reasonable and elegant, facilitating easy operation and maintenance.
Single unit available with both CE and UL certifications, supporting barrier-free global sales. Our dry-type isolation transformers cover but are not limited to the following application scenarios: As common electrical equipment in industrial and civil power distribution systems, dry-type transformers have specific selection criteria due to their structural features and applicable environments. They are widely deployed in locations with strict fire and explosion protection requirements, including high-rise buildings, metro stations, hospitals, data centers and other indoor power distribution sites. With air or resin as insulation and cooling medium without oil filling, they gain wide recognition for outstanding safety and environmental performance.
Are you looking for a dry type isolation transformer solution suitable for your project? Contact us for professional advice.
| Parameter Item | GB / IEC (Domestic, Middle East, Africa) | North America UL (United States) | Description |
| Rated Capacity | 10~2500kVA | 10~2500kVA | Apparent power in kVA, single-phase / three-phase optional |
| Rated Voltage Combination | Common ratings: 380V/380V, 400V/400V; equipped with ±2×2.5% off-circuit tap regulation | Common ratings: 480V/480V, 480V/208V; tap positions customized on demand | The primary and secondary sides of isolation transformers can adopt identical voltage to achieve electrical isolation |
| Connection Group | Dyn11 (mainstream for three-phase); Ii0 for small-capacity single-phase models | Dy1 (mainstream for three-phase) | Dyn11 features stronger harmonic suppression, ideal for buildings and energy storage systems |
| Rated Frequency | 50Hz (60Hz compatible) | 60Hz | Iron core redesign and no-load loss adjustment required for frequency changes |
| Rated Current | Three-phase: I=S/(√3U); Single-phase: I=S/U | Same formula | Calculated directly based on capacity and voltage |
| Parameter Item | GB / IEC | North America UL | Description |
| Insulation Class | Class F (temperature rise limit: 100K), Class H (temperature rise limit: 125K) | Class F / Class H, temperature rise tested per UL standards | Class H is preferred for high-temperature environments in the Middle East |
| Power Frequency Withstand Voltage | Low-voltage winding: 3kV/1min; high-voltage winding rated per voltage class | Low-voltage winding ≥4kV/1min; high-voltage winding rated per UL classes | Destructive test to verify main insulation strength |
| Induced Withstand Voltage | 2×rated voltage; test frequency＞100Hz, test time t=120×(50/f), minimum 15s | Same principle, test voltage and duration comply with UL specifications | Inspects interlayer and turn-to-turn winding insulation |
| Insulation Resistance | Measured with 2500V megohmmeter; ≥1000MΩ at ambient temperature, absorption ratio ≥1.3 | Same measurement logic with stricter acceptance thresholds | Non-destructive test to judge insulation dampness |
| Partial Discharge Level | Epoxy cast type ≤10pC | ≤5pC for stringent projects | High partial discharge standards apply to new energy and energy storage projects |
| Parameter Item | GB / IEC | North America UL | Description |
| No-load Loss | Adopts high-grade grain-oriented silicon steel, complying with national energy efficiency limits; fixed values at 50Hz | Must meet DOE energy efficiency certification, loss recalculated for 60Hz | Loss generated by iron core during no-load operation |
| Load Loss | Measured winding copper loss at reference temperature: 120℃ for Class F, 145℃ for Class H | Tested at temperatures specified by DOE | Heat loss of windings under rated load |
| Short-circuit Impedance | 4% and 6% common for power distribution | 5.75% and 7% common | Higher impedance delivers stronger short-circuit resistance yet larger voltage drop |
| No-load Current | 1%~3% of rated current under rated voltage | Same range, subject to energy efficiency requirements | Excitation current of iron core; lower value with higher-quality silicon steel |
| Parameter Item | Details |
| Cooling Mode | AN Natural Air Cooling, AF Forced Air Cooling; fan activation boosts overload capacity by 30%~50% |
| Temperature Control System (Standard Pt100 temperature probes) | Fan starts at 80℃; high-temperature alarm at 130℃; over-temperature trip at 150℃ |
| Noise Level | 50–60dB under rated operating conditions, suitable for indoor environments such as hospitals and office buildings |
| Short-circuit Withstand Capacity | Tolerates 2-second internal and external short-circuit current impact without winding deformation |
What is the maximum capacity of dry-type transformers manufactured by CHBEB?
30kVA to 20MVA. Contact us for special customized requirements.
As a transformer manufacturer, what raw materials does CHBEB select?
We adopt different materials in accordance with capacity standards and customized client demands, including high-permeability low-loss cold-rolled grain-oriented silicon steel sheets, enameled wires with heat resistance up to 180℃, high-temperature resistant BT terminal blocks and insulation boards. Clients with strict quality requirements are welcome to consult us.
We will reply to you within 1–2 business days.Please pay attention to the email with the suffix”@chbebpower.com”.
