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The cast-resin coil dry-type transformer represents the high-end tier of power distribution. Distinct from standard impregnation processes, its windings are integrally cast in a dedicated vacuum mold using high-strength epoxy or specialized resins. This forms an impenetrable, rock-solid dielectric shell around the oxygen-free copper coils. Delivering unparalleled resistance to short-circuits, fire, moisture, and dust, it is the ultimate choice for highly demanding environments such as high-rise skyscrapers, Tier IV data centers, subway systems, and top-tier hospitals.
Core Parameters:
• Structure: Integral Vacuum Mold Casting (Ultra-low partial discharge).
• Voltage Configuration: 10kV / 20kV / 35kV to 0.4kV.
• Insulation Class: Class F (155℃) / Class H (180℃).
Product Features
Unlike standard dipping, the copper coils are placed in a mold and injected with liquid resin under strict vacuum. This creates a dense, bubble-free, rock-hard insulation shell.
The solid-cast resin structure provides immense resistance to the massive electromagnetic forces generated during short-circuits, preventing coil deformation or cracking.
100% oil-free and utilizing premium flame-retardant epoxy resin, it acts as a self-extinguishing barrier. It is the safest choice for densely populated high-rise buildings and subways.
Pairs the cast oxygen-free copper coils with a 45° step-lap high-permeability silicon steel core, minimizing both no-load iron losses and operational acoustic noise.
Standard Natural Air (AN) cooling provides silent base loads, while Forced Air (AF) fan activation securely boosts the operational capacity by 30%~50% during demand spikes.
The impenetrable resin casting blocks out extreme humidity, coastal salt spray, and industrial dust, rendering the unit virtually maintenance-free across its lifetime.
Key Specifications (Cast Coil Series)
| Parameter | Typical Value | Description |
| Rated Capacity | 10kVA ~ 2500kVA | Scalable from local precision instruments to massive commercial substation hubs. |
| Rated Voltage | HV: 10kV / 20kV / 35kV LV: 0.4kV | Highly precise distribution output to directly power 3-phase machinery and grids. |
| Vector Group | Dyn11 / Yyn0 | Standard connection ensuring robust handling of severe unbalanced electrical loads. |
| Insulation Class | Class F (155℃) / Class H (180℃) | Premium thermal endurance ensuring stable operation without insulation breakdown. |
| Partial Discharge | Extremely Low | Integral vacuum casting eliminates air pockets, ensuring zero internal arcing risks. |
| Cooling Method | AN / AF | Natural air handles standard loads; Forced air (AF) safely boosts capacity by 30%~50%. |
Full Series Technical Reference (30kVA ~ 3150kVA)
| Capacity (kVA) | Impedance (%) | No-Load Loss (W) | Load Loss (W) | Total Weight (kg) | Dimensions W×D×H (mm) |
| 30 | 4.0 | 180 | 600 | 250 | 800×600×900 |
| 50 | 4.0 | 240 | 870 | 320 | 850×650×950 |
| 100 | 4.0 | 380 | 1500 | 550 | 950×700×1000 |
| 160 | 4.0 | 540 | 2000 | 750 | 1050×750×1050 |
| 200 | 4.0 | 620 | 2400 | 880 | 1100×800×1100 |
| 250 | 4.0 | 720 | 2800 | 1050 | 1150×800×1150 |
| 315 | 4.0 | 880 | 3400 | 1250 | 1200×850×1200 |
| 400 | 4.0 | 980 | 4100 | 1450 | 1250×900×1250 |
| 500 | 4.0 | 1160 | 4900 | 1700 | 1300×950×1300 |
| 630 | 4.5 | 1340 | 6200 | 1950 | 1350×1000×1350 |
| 800 | 4.5 | 1520 | 7500 | 2300 | 1400×1000×1400 |
| 1000 | 4.5 | 1770 | 8800 | 2700 | 1450×1050×1450 |
| 1250 | 4.5 | 2090 | 10800 | 3200 | 1550×1100×1550 |
| 1600 | 4.5 | 2450 | 13200 | 3800 | 1650×1150×1650 |
| 2000 | 4.5 | 3000 | 16000 | 4500 | 1750×1250×1800 |
| 2500 | 4.5 | 3600 | 19500 | 5300 | 1850×1300×1900 |
| 3150 | 4.5 | 4300 | 24000 | 6500 | 2000×1400×2100 |
* The comprehensive table above displays the standard parameter range for dry-type technology. Cast-coil technology typically yields highly stable dimensions matching these standard footprints, ensuring seamless upgrades.
FAQ
While both are excellent dry-type technologies, Integral Cast Coil transformers represent the high-end tier for critical applications due to three main factors:
1) Structural Rigidity: In a cast coil transformer, the copper windings are placed inside a mold and flooded with epoxy resin under vacuum. Once cured, it forms a thick, solid block of resin. This provides vastly superior mechanical strength to withstand extreme short-circuit forces compared to the thin varnish layer applied in VPI processes.
2) Absolute Moisture & Dust Barrier: The thick resin casting completely seals the conductors. Unlike VPI, which can be susceptible to long-term harsh humidity if the varnish cracks, cast coils are practically impervious to heavy moisture, chemical vapors, and heavy industrial dust.
3) Partial Discharge Elimination: The strict vacuum casting process removes 100% of air bubbles from within the winding block. This results in an exceptionally low partial discharge rate, ensuring the transformer will not suffer from internal electrical breakdown over its 25+ year lifespan.
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E-mail: junqiu.wang@czguanghui.cn
jocelyn.duan@czguanghui.cn
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Mobile: 0086-15380068868
