Top 10 Electrical Transformer Repair Services in USA

Electrical transformer repair services in USA play a critical role in ensuring the uninterrupted power supply for industrial, commercial, and utility networks. Transformers are the heart of electrical systems — stepping up and stepping down voltages efficiently. Over time, due to electrical faults, insulation breakdowns, or oil leaks, transformers require professional repair and maintenance. Choosing a reliable service provider not only saves costs but also extends the transformer’s lifespan and enhances system reliability.

This guide explores the top 10 electrical transformer repair services in USA, their core expertise, and why they stand out in the industry. Whether you’re managing a substation, manufacturing facility, or renewable energy plant, selecting the right repair partner is essential for safe and efficient operations.

Key takeaway

• The U.S. transformer repair industry is driven by decades of expertise, modern testing facilities, and certified technicians who ensure reliability, safety, and compliance with IEEE and NETA standards.
• Quality transformer repair isn’t just about fixing faults — it’s about restoring full functionality through diagnostics, rewinding, and advanced testing.
• Selecting one of the top transformer repair companies in the U.S. ensures longer equipment life, reduced downtime, and lower maintenance costs.

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1. ABB Power Service Division

ABB, now part of Hitachi Energy, remains one of the most trusted names in electrical transformer repair services in USA. The company offers full-service transformer maintenance, diagnostics, and life extension programs. ABB’s transformer repair facilities across the U.S. are equipped with vacuum drying ovens, oil filtration units, and digital testing systems.

They provide services for:

• Power transformers up to 800 MVA
• Distribution transformers
• Transformer rewinding and re-insulation
• On-site repair and testing

Why ABB stands out:
Their combination of predictive maintenance software and expert field engineers helps utilities reduce unplanned outages and improve transformer performance.

2. Siemens Energy Transformer Services

Siemens Energy is a global leader offering comprehensive transformer repair, testing, and refurbishment solutions across the United States. Their U.S.-based service centers provide expert handling for power and distribution transformers used in industrial, transmission, and generation applications.

Siemens uses proprietary diagnostics tools such as TRACER and Transformer Monitoring Systems to identify aging components before failure occurs.

Core services:

• On-site oil filtration and degassing
• Core and coil replacement
• Tap changer repairs
• Dielectric testing

Their engineers follow ANSI/IEEE C57 standards, ensuring reliability and precision. Siemens Energy’s focus on digital maintenance and sustainability makes them one of the most preferred service partners for high-voltage equipment.

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3. SPX Transformer Solutions

SPX Transformer Solutions (formerly Waukesha Electric Systems) is one of the leading companies providing electrical transformer repair services in USA. Known for its large-scale repair centers and OEM expertise, SPX handles transformers up to 500 kV.

Their facilities include in-house winding shops, vacuum dry-out systems, and oil processing plants to ensure thorough refurbishment.

Key services include:

• Transformer rewind and re-core
• Oil reclaiming and degassing
• Bushings and gaskets replacement
• Factory acceptance testing

Advantages: SPX offers complete life-cycle management and custom engineering for utility and industrial clients.

4. National Field Services

National Field Services (NFS) is a U.S.-based leader specializing in transformer testing, repair, and maintenance for commercial, industrial, and utility sectors. Their technicians are NETA-certified and trained to handle both dry-type and oil-filled transformers.

NFS provides both in-shop and on-site transformer repair. Their rapid-response mobile repair units allow quick restoration of failed transformers.

Their services include:

• Transformer oil analysis and replacement
• Insulation resistance testing
• Core and coil rewinds
• Thermal imaging diagnostics

Why choose NFS: Their field expertise and fast response time make them ideal for critical power facilities like hospitals, data centers, and manufacturing plants.

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5. Delta Star Inc.

Delta Star Inc. is widely recognized for both transformer manufacturing and field repair services in the U.S. Their repair capabilities cover mobile substations and large power transformers, ensuring minimal downtime for customers.

They provide:

• Transformer inspection and condition assessment
• Field rewinding
• Load tap changer replacement
• Oil processing and reclamation

Strengths: Delta Star’s on-site repair service reduces shipping time, saving both cost and downtime. Their engineers follow NERC and IEEE maintenance protocols.

Their strong reputation in utility-grade transformer handling makes them a preferred vendor for electric cooperatives and transmission operators.

6. SDMyers Transformer Maintenance

For over 60 years, SDMyers has focused exclusively on transformer health and maintenance. Their technical approach combines preventive testing with predictive analytics to minimize transformer failures.

They provide transformer services throughout the USA, including:

• Comprehensive oil testing
• Insulation drying
• Vacuum filling
• Complete rebuilds and rewinds

SDMyers also offers a cloud-based monitoring platform called Transformer Dashboard, allowing real-time health tracking.

Why SDMyers is a top choice: Their focus on transformer reliability and energy efficiency makes them a leading name in the U.S. repair sector.

7. Reinhausen Manufacturing Inc. (MR)

Reinhausen Manufacturing, the U.S. division of Maschinenfabrik Reinhausen (MR), provides high-end electrical transformer repair services in USA, focusing on on-load tap changer systems and diagnostic maintenance.

They provide complete overhaul services for power and distribution transformers. Their expertise includes:

• Tap changer replacement and diagnostics
• Oil filtration and regeneration
• Winding resistance measurement
• Advanced field testing

Why MR is unique: Their deep specialization in on-load tap changer systems gives them a competitive edge, ensuring smoother voltage regulation in transformers.

8. Electric Power Systems (EPS)

Electric Power Systems offers comprehensive electrical testing, repair, and commissioning services across North America. Their transformer repair division provides end-to-end support for both dry and oil-filled units.

EPS technicians use Doble testing, dissolved gas analysis (DGA), and partial discharge testing to detect problems early.

Their services include:

• Transformer oil regeneration
• Power factor testing
• Coil and core drying
• Protective relay coordination

Why clients trust EPS: Their expertise spans from substation commissioning to transformer rehabilitation, making them a one-stop provider for electrical infrastructure.

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9. Shermco Industries

Shermco Industries is one of the largest independent electrical testing and repair firms in North America. They offer transformer repair, maintenance, and field testing services for industrial and utility clients.

Their repair workshops are equipped for both medium- and high voltage transformers. Shermco’s technical staff includes PEs (Professional Engineers) and NETA Level IV technicians.

Key offerings:

• Core and coil replacement
• Transformer oil regeneration
• Failure analysis and diagnostic testing
• Acceptance and maintenance testing per NETA standards

Shermco advantage: Their integrated testing, engineering, and repair solutions provide unmatched reliability in transformer maintenance.

10. HPS (Hammond Power Solutions) Field Services

Hammond Power Solutions (HPS) is a North American manufacturer and service provider offering specialized electrical transformer repair services in USA. They handle both custom-built and standard distribution transformers.

HPS service engineers specialize in diagnosing insulation issues, rewinding, and thermal performance testing. They also supply replacement parts for obsolete models, reducing downtime.

Core capabilities:

• Rewinding of dry-type and cast resin transformers
• Short-circuit and impulse testing
• Transformer load and temperature monitoring
• Preventive maintenance programs

Why HPS stands out: Their combination of manufacturing expertise and responsive service ensures high-quality, durable repairs.

Comparison of Top 10 Transformer Repair Services in USA

Factors to Consider When Choosing a Transformer Repair Service

Choosing the right repair company can save significant downtime and cost. Consider the following factors:

1. Certifications and Standards: Look for NETA, IEEE, or ISO-certified providers.
2. Repair Capability: Ensure they handle your voltage class and transformer type.
3. Emergency Response: 24/7 service is crucial for critical applications.
4. Testing Facilities: The presence of advanced testing systems ensures accuracy.
5. Warranty and Support: Always check the service warranty and after-repair monitoring.

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Future of Transformer Repair Industry in the USA

The demand for transformer repair services is expected to rise due to aging grid infrastructure and renewable energy integration. Companies are investing in AI-based predictive maintenance, real-time monitoring systems, and eco-friendly insulating oils.

Digital twins and smart diagnostics are shaping the next generation of electrical transformer repair services in USA, enabling remote condition monitoring and predictive fault detection.

Conclusion

Reliable electrical transformer repair services in USA ensure safety, stability, and cost efficiency across all electrical systems. The top companies mentioned — from ABB and Siemens to Shermco and SDMyers — have proven expertise in restoring transformers to optimal condition through precise diagnostics, rewinding, oil treatment, and performance testing.

Selecting the right service partner depends on your specific transformer type, location, and maintenance requirements. With the right provider, your transformer can achieve decades of efficient service life with minimal downtime.

To explore further and find industry-leading equipment providers, visit top power and distribution transformers suppliers — your trusted source for premium transformer solutions across the USA.

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