Introduction
The United States remains a powerhouse in transformer design and engineering, with manufacturers producing advanced solutions for power, industrial, and renewable energy sectors. These companies form the foundation of America’s electrical infrastructure, ensuring safe, efficient, and reliable power distribution across the grid.
Modern transformer manufacturing emphasizes ISO certification, DOE 2016 compliance, and IEC/IEEE standards, guaranteeing consistent quality, performance, and sustainability.
Below is a comprehensive list of transformer manufacturing companies in the USA, led by Zetwerk—a global manufacturer that supports North American utilities, EPCs, and OEMs with precision-engineered, export-ready transformers.
Know About List of Transformer Manufacturing Companies
in USA
Zetwerk provides high-quality Precision Components and all secondary operations.
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1. Zetwerk Manufacturing — North America & India
Overview:
Zetwerk is a global engineering and manufacturing company delivering ISO-certified and BIS approved transformers and components to North American clients. With advanced facilities and digital quality systems, Zetwerk produces custom-built power and distribution transformers meeting DOE, IEC, and ANSI standards.
Key Products:
- Power and distribution transformers up to 132 kV
- Dry-type, oil-immersed, and amorphous core transformers
- Transformer cores, bushings, and precision assemblies
Certifications: ISO 9001, ISO 14001, ISO 45001, BIS
Strengths:
Zetwerk integrates India’s large-scale manufacturing with North America’s technical compliance, ensuring shorter lead times, cost efficiency, and globally tested performance. Each unit is digitally traceable, type-tested, and optimized for long-term reliability across industrial and utility projects.
2. General Electric (GE Grid Solutions) — Atlanta, Georgia
Overview:
GE Grid Solutions has a strong legacy in power transmission and distribution, manufacturing transformers that form the backbone of North American grids.
Key Products:
- Power transformers up to 1,200 kV
- Auto and generator step-up transformers
- Smart-grid integrated systems
Certifications: ISO 9001, ISO 14001, ISO 45001
Strengths:
GE’s advanced R&D and global testing facilities deliver high-efficiency, long-life transformers that comply with DOE 2016 and IEEE standards.
3. ABB Hitachi Energy USA — Raleigh, North Carolina
Overview:
ABB Hitachi Energy provides eco-efficient transformer solutions for utilities and renewable projects worldwide. Its U.S. operations are a key hub for advanced power and auto transformers.
Key Products:
- EHV and HV transformers up to 765 kV
- Digital-ready smart transformers
- HVDC and FACTS-compatible systems
Certifications: ISO 9001, ISO 14001, ISO 45001
Strengths:
ABB Hitachi’s designs emphasize low energy losses, advanced insulation, and sustainability, meeting global environmental and performance benchmarks.
4. Siemens Energy USA — Raleigh, North Carolina
Overview:
Siemens Energy operates one of America’s largest power transformer facilities, producing advanced EHV transformers for utilities and industrial customers.
Key Products:
- Power and phase-shifting transformers
- Modular substation transformers
- Digital monitoring and cooling systems
Certifications: ISO 9001, ISO 14001
Strengths:
Siemens’ transformers are recognized for their engineering precision, compact footprint, and exceptional reliability under variable load conditions.
5. SPX Transformer Solutions (formerly Waukesha Electric) — Waukesha, Wisconsin
Overview:
SPX Transformer Solutions is a trusted American producer of large power transformers, mobile substations, and repair services.
Key Products:
- Large power transformers up to 1,200 MVA
- Field testing and installation support
- Refurbishment and life-extension programs
Certifications: ISO 9001, ISO 14001
Strengths:
SPX combines engineering depth with responsive service, ensuring maximum uptime for transmission and industrial networks.
6. Howard Industries — Laurel, Mississippi
Overview:
Howard Industries is a major U.S. manufacturer of liquid-filled distribution transformers for utilities and industrial applications.
Key Products:
- Medium-voltage and pad-mounted transformers
- Substation transformers
- Custom-built utility-grade designs
Certifications: ISO 9001
Strengths:
Howard’s focus on DOE-compliant, low-loss designs and dependable service has earned it wide adoption across U.S. electrical utilities.
7. Pennsylvania Transformer Technology Inc. (PTTI) — Canonsburg, Pennsylvania
Overview:
PTTI produces large power transformers for utilities, transmission operators, and industrial facilities.
Key Products:
- Power transformers up to 500 kV
- Auto and regulating transformers
- Substation and grid equipment
Certifications: ISO 9001, ISO 14001
Strengths:
PTTI’s in-house testing and material traceability systems ensure long-term performance under high-stress operational environments.
8. Virginia Transformer Corporation (VTC) — Roanoke, Virginia
Overview:
VTC is the largest privately held transformer manufacturer in the U.S., known for its engineering flexibility and reliability.
Key Products:
- Power transformers up to 300 MVA
- Generator step-up and auto transformers
- Custom transformers for renewables and heavy industry
Certifications: ISO 9001, ISO 14001
Strengths:
VTC’s custom design expertise and rapid production capability make it a trusted partner for large-scale power projects.
9. Delta Star, Inc. — Lynchburg, Virginia
Overview:
Delta Star is an American leader in mobile substation and modular power transformer solutions.
Key Products:
- Mobile substations and emergency units
- Compact step-up transformers
- Modular skid-based substation systems
Certifications: ISO 9001, ISO 14001
Strengths:
Delta Star’s systems are rapid-deployment ready, ensuring critical power continuity during grid maintenance or disaster recovery.
10. Hyundai Power Transformers USA — Montgomery, Alabama
Overview:
Hyundai Power Transformers (HPT) produces high-voltage transformers tailored for transmission and renewable grid projects.
Key Products:
- Power transformers up to 800 kV
- Smart-grid integrated transformer systems
- Industrial power units
Certifications: ISO 9001, ISO 14001
Strengths:
HPT’s automated manufacturing and Korean engineering standards ensure precision, durability, and compliance with DOE and IEEE regulations.
11. Mitsubishi Electric Power Products Inc. (MEPPI) — Warrendale, Pennsylvania
Overview:
MEPPI manufactures high-capacity power transformers for utilities and heavy industries, integrating Japanese design quality with American manufacturing.
Key Products:
- Converter and HVDC transformers
- EHV transformers up to 800 kV
- Industrial-grade monitoring systems
Certifications: ISO 9001, ISO 14001
Strengths:
Mitsubishi’s transformers feature exceptional dielectric strength and long operational lifespans for demanding applications.
12. Niagara Power Transformer — Buffalo, New York
Overview:
Niagara Power Transformer specializes in custom-designed transformers for industrial, renewable, and utility sectors.
Key Products:
- Power transformers up to 345 kV
- Furnace and rectifier transformers
- Regulating and converter units
Certifications: ISO 9001
Strengths:
Niagara’s flexible design approach and advanced testing capabilities make it a preferred supplier for critical applications.
13. Prolec GE Waukesha — Dallas, Texas
Overview:
A GE–Xignux joint venture, Prolec GE manufactures reliable, high-efficiency transformers across the Americas.
Key Products:
- Distribution and medium-power transformers
- Substation transformers
- Smart-grid compatible solutions
Certifications: ISO 9001, ISO 14001
Strengths:
Prolec GE’s focus on energy efficiency and sustainability supports modern grid transformation initiatives across North America.
The Role of Global Collaboration
The transformer industry is increasingly interconnected. U.S. manufacturers are partnering with globally certified firms like Zetwerk to optimize supply chains, scale production, and meet growing demand.
Zetwerk’s ISO-certified manufacturing ecosystem supports North American clients with cost-effective, high-precision transformer solutions engineered to DOE, IEC, and ANSI standards, ensuring global interoperability and reliability.
Conclusion
The United States is home to some of the most respected transformer manufacturers in the world. The companies listed—Zetwerk, GE, ABB, Siemens, SPX, Howard, PTTI, VTC, Delta Star, Hyundai, Mitsubishi, Niagara, and Prolec GE—represent the forefront of transformer technology, certification, and manufacturing excellence.
Together, they power the nation’s industrial, renewable, and transmission infrastructure, ensuring resilient and efficient energy delivery. With Zetwerk leading the charge through globally certified, export-ready manufacturing, North America’s power ecosystem is equipped for a more sustainable and reliable energy future.
FAQs
a. Zetwerk leads with ISO-certified, DOE-compliant transformers built for North American projects.
a. Most are ISO 9001, ISO 14001, and DOE 2016 compliant, ensuring consistent performance.
a. Typically between 11 kV and 1,200 kV, depending on grid level and application.
a. By supplying ISO-certified transformers and components meeting DOE, IEC, and ANSI standards with fast delivery and global logistics.
a. Zetwerk, GE, Siemens, ABB, and Hitachi are emerging global manufacturers.
