---- July 9th 2025 ----

www.ccr.gov
CAGE Code: 5DME2
ITAR Registration Code: M28889
Call: 1 (800) 377-3244
Monday to Friday 8 A.M. - 5 P.M. (Pacific Time)
E-mail questions and requirements to: sales@coilws.com

Pricing is subject to change depending on product availability and backorders.
*Please Note: Items without price are listed for CWS' capability purposes.

Single and 3-Phase 50/60 Hz, Dry and Oil-Filled Padmount Transformers

High-Efficiency Oil-Filled Distribution Transformers | CWS

High-Efficiency Oil-Filled Distribution Transformers | CWS

Powering Industries with Reliable & Energy-Saving Solutions

CWS designs and manufactures high-performance distribution transformers (up to 1000 KVA / 1 MVA) for industrial, commercial, military and utility applications.

Types of Distribution Transformers

  • Dry-type and oil-filled transformers
  • Single-phase and three-phase configurations
  • Voltage support from 120V to 22,900V

Transformer Technologies

1. Conventional Silicon Steel Core Transformers

  • Grain-oriented silicon steel lamination
  • Available as oil-filled (Mineral Oil or FR3) or dry-type
  • Fail-safe construction with long service life

2. Amorphous Metal Transformers (AMT)

  • 75% lower core losses using Metglas or nanocrystalline cores
  • Ideal for variable load applications like renewable energy
  • Preferred by industry leaders such as Shell Oil

Why Choose CWS Transformers?

  • High Efficiency - Reduced core & copper losses
  • Custom Designs - Tailored to industrial and utility needs
  • Durability - Long-lasting dielectric fluids in oil-filled designs
  • Future-Ready - Supports AMT technology for sustainability

Technical Specifications

FeatureConventional (Si-Fe)Amorphous (AMT)
Core MaterialGrain-oriented silicon steelMetglas/Nanocrystalline
Core LossStandard75% Lower
Efficiency at Low LoadModerateExcellent
SizeCompactLarger

Applications

  • Utility distribution
  • Military and industrial installations
  • Oil & gas fields
  • Renewable energy infrastructure

Medium Voltage Oil-Filled Transformers

MV oil-filled transformers operate from 2.4 kV to 34.5 kV and support up to 69 kV. Used in utilities, industry, and commercial power, they use mineral oil or FR3 esters for efficient insulation and cooling.

Primary Applications

  • Utility distribution networks (e.g., 34.5 kV -> 4.16 kV)
  • Industrial plants and commercial buildings
  • Renewable energy grid interfacing

Typical Ratings

  • Voltage Classes: 5-35 kV
  • Power: 500 kVA to 20 MVA
  • Cooling Types: ONAN, ONAF, KNAN

Advantages of Oil-Filled vs. Dry-Type

FeatureOil-FilledDry-Type
CoolingBetterAir-cooled
VoltageUp to 345 kVUp to 35 kV
Lifespan30+ years20-30 years
CostLower for high ratingsHigher
MaintenanceOil checksMinimal
Fire RiskHigherLower

Maintenance Practices

  • Oil testing (DGA - Dissolved Gas Analysis)
  • Infrared inspections
  • Bushing and winding resistance checks
  • Leak detection

Future Trends

  • Biodegradable ester fluids
  • IoT-based smart monitoring
  • Compact, modular designs


Disclaimer: Coil Winding Specialist, Inc., its affiliates, agents, and employees acting on behalf of Coil Winding Specialist, Inc. (collectively, CWS) disclaim any and all liability for any errors, inaccuracies or incompleteness contained herein or in any other disclosure relating to any product. CWS reserves the right at any time and from time to time to make changes to design, technical specification, or construction of any product listed on this website without notice. CWS also reserves the right to discontinue or limit sale of any product or service available throughout this website on temporary or permanently basis without notice. CWS highly recommends customers not to use its products offered on this website for inappropriate use and applications. Products should be tested for its suitability by prospective customers in all possible applications and conditions. Customers using or selling CWS products for use in other than recommended applications do so entirely at their own risk and agree to fully indemnify CWS from any damages arising or resulting from such use or sale.

WARNING: This product can expose you to chemicals which is [are] known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go towww.P65Warnings.ca.gov.


Any Comments, Suggestions or Questions? Contact us!
Email: sales@coilws.com
CWS 353 West Grove Ave. Orange, California 92865
Call us Toll Free: 1-800-679-3184 or 1 (800) 377-3244

Tel: (714) 279-9010, Fax: (714) 279-9482

Copyright 2008, Coil Winding Specialist, Inc
Updated July, 2013

CAGE Code: 5DME2(Registered with www.ccr.gov)