Cast Resin Dry Type Transformer – Full Guide for Buyers & Engineers

Cast resin dry type transformers are among the safest, most durable, and widely used dry-type transformers for commercial, industrial, infrastructure, and high-rise applications. They use epoxy resin casting for high mechanical strength, fire resistance, and low maintenance.

This blog covers structure, features, advantages, applications, specifications, and key buying points.

What Is a Cast Resin Dry Type Transformer

A cast resin dry type transformer is a transformer where the high-voltage and low-voltage windings are

• wound with copper or aluminum conductor
• vacuum-cast with epoxy resin under pressure
• cured to form a solid, rigid insulation structure

No oil is used, making it fire-safe, explosion-proof, and environmentally friendly.

Main Structure & Features

1. Cast Resin Windings
   • Epoxy resin + quartz sand filler
   • High mechanical strength, resistant to cracking, moisture, dust, and corrosion
2. Core
   • High-grade cold-rolled silicon steel
   • Low no-load loss, low noise
3. Enclosure
   • IP20, IP23, IP30, IP42, IP54
   • Protect against contact, rain, dust, and foreign objects
4. Cooling System
   • AN (Air Natural)
   • AF (Air Forced) with cooling fans
5. Temperature Monitoring
   • Built-in PT100 temperature sensors
   • Over-temperature alarm & fan automatic control

Key Advantages

• Flame retardant & fire safe – suitable for indoors, basements, high-rises, hospitals, subways
• Moisture & dust resistant – works in harsh, humid, or dirty environments
• Low partial discharge & high reliability
• Long service life – up to 30 years
• Maintenance-free – no oil leakage, no oil replacement
• Environmentally friendly – no oil contamination risk
• Good short-circuit withstand strength
• Low noise

Typical Applications

• High-rise buildings, hotels, shopping malls
• Hospitals, schools, data centers
• Airports, subway stations, tunnels
• Factories, chemical plants, mines
• Power stations, offshore platforms
• Indoor substations, densely populated areas

Common Specifications

• Capacity: 10kVA – 2500kVA (up to 10MVA for special)
• Voltage class: 10kV, 11kV, 15kV, 20kV, 35kV
• Phase: 3-phase
• Vector group: Dyn11 (most popular for export)
• Insulation class: F (155°C) or H (180°C)
• Frequency: 50Hz / 60Hz
• Standards: IEC 60076, GB, CE, IEEE

Cast Resin vs. VPI Dry Type Transformer

• Cast resin:
  • Epoxy cast solid
  • Higher strength, better moisture/dust resistance
  • Higher cost
  • For demanding environments
• VPI (Vacuum Pressure Impregnated):
  • Paint-impregnated winding
  • Lower cost
  • Suitable for cleaner indoor environments

Why Choose a Professional Manufacturer

• Mature casting & vacuum pouring technology
• Strict raw material control
• Full type test & routine test for each unit
• Complete certificates: CE, IEC, ISO, test report
• Stable quality for export markets
• Custom design for special voltage & capacity

Conclusion

Cast resin dry type transformers are the top choice for safety-critical and indoor applications.

They provide high reliability, low maintenance, and long service life while meeting strict international standards.

If you need a safe, durable, and export-grade transformer, cast resin dry type is the ideal solution.