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Encapsulated Transformer

Product Overview & Application


Encapsulated (Potted) Transformers (also referred to as Epoxy Resin Encapsulated) are designed for applications where the environmental conditions would not permit a general purpose ventilated dry type transformer. The entire transformer core & coil is encased in a silica sand / polyurethane mixture which protects the windings from any airborne contaminants and moisture. 

Typical areas of use include:

  • Corrosive Environments: Petro-Chemical, steel, pulp and paper industries
  • Damp conditions: Mines, pump-houses underground or rooftop service areas
  • Industrial applications: processes with high degree of airborne dust or conductive particles

Features & Benefits


  • Mixture of silica sand resin forming a solid mass completely encloses and protects the core and coil, also significantly reduces audible noise.
  • Windings utilize Class 220°C Insulating rated for 150°C Rise, but designed to operate at 115°C maximum.
  • The transformer's core is solidly grounded.
  • Enclosure constructed from heavy gauge steel, coated with ASA#61 grey powder paint
  • Suitable for NEMA/CSA Type 3R and Type 4 Enclosure applications for both indoor and outdoor
  • Spacious wiring compartment, cool and easily accessible (bottom or front access may depend on size)

Product Specification

Capacity  3 to 125 kVA Single Phase and 5 to 150 kVA Three Phase
Voltage Class  600V
Cooling  Self Cooled (ANC)
Frequency  60Hz (50/60Hz Optional)
Conductors  Copper (Cu) or Aluminum (Al) Windings
Insulation System  200°C (130°C rise) (Optional 115°C & 80°C Rise Available)
Impregnation  N/A (Core & Coil Are Encapsulated In a Block of Polyeurethane and Silica Sand)
Primary Taps  Typically +/-2 x 2.5% Raps (Refer To Dry Type Distribution Transformer Catalog)
Sound Level  Meets NEMA ST-20
Enclosure Type  Type 3R Indoor/Outdoor (Refer to Catalog)
Enclosure Finish  ANSI/ASA 61 Grey
Warranty  12 Months (See Warranty and Limitations)
Quality System  ISO 9001:2015 Quality Management System
  • CSA Certified
  • UL Listed
Reference Standards
  • CSA C22.2 No 47
  • CSA C9
  • IEEE C57.12.01
  • IEEE C57.12.91
  • NEMA ST-20
Optional Features & Accessories
  • Suitable for 50Hz Nominal Frequency
  • 115°C or 80°C Remperature Rise
  • Thermal Sensing & Indication
  • Thermometers (Analog/Digital)
  • Thermostat Alarm / Trip (N.O. /N.C. contacts)
  • Electrostatic Shielding
  • K-Factor Rated to Handle Current Harmonics (K4, K9, K13, K20)
  • Surge Protection Devices
  • External Anti-Vibration Pads
  • Type 4 or 4X Enclosure 
  • 304 or 316L Stainless Steel Enclosure
  • Custom Enclosure Finish (Color)