Company lists · Data refreshed September 2026

Top 25 Transformer diagnostics companies based in the United States

RevenueBase identified 285 transformer diagnostics companies headquartered in the United States as of September 2026 and tracks 8,043 professional contacts across them, including 3,092 with verified work emails. Houston is the largest hub.

This list covers transformer diagnostics companies headquartered in the United States, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 22, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 22, 2026 86% judged on-target in blind review
285Companies
8,043Contacts tracked
3,092Verified emails
Explore this list → Free signup · no credit card · 500 free credits

The 25 largest transformer diagnostics companies based in the United States

Ranked by team size
Top 25 of 285 transformer diagnostics companies based in the United States, ranked by team size, largest first. Data refreshed Sep 22, 2026. RevenueBase Smart Search rates how each company's information relates to transformer diagnostics companies: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#CompanyRevenueBase Smart SearchHeadquartersEmployeesContacts
1Indirect evidenceIrving, TX, United StatesHQ checked Sep 22, 20261,001-5,0001,221 contacts →

Indirect evidence

“Shermco Industries is a provider of safe, reliable testing, repair, professional training, electrical outage planning, maintenance and analysis of rotating apparatus and…”

Source: RevenueBase Database · checked Sep 22, 2026
2Indirect evidenceMaryland Heights, MO, United StatesHQ checked Sep 22, 2026501-1,000653 contacts →

Indirect evidence

“Electric Power Systems is an independent electrical testing & engineering organization.”

Source: RevenueBase Database · checked Sep 22, 2026
3Partial evidenceMarlborough, MA, United StatesHQ checked Sep 22, 2026501-1,000619 contacts →

Partial evidence

“Doble is the world’s most trusted brand in electrical diagnostics.”

Source: RevenueBase Database · checked Sep 22, 2026
4Partial evidenceGreer, SC, United StatesHQ checked Sep 22, 2026201-500286 contacts →

Partial evidence

“Maddox serves the commercial, industrial, utility, and renewables segments of the transformer market.”

Source: RevenueBase Database · checked Sep 22, 2026
5Indirect evidenceHuntersville, NC, United StatesHQ checked Sep 22, 2026201-500274 contacts →

Indirect evidence

“Structural Integrity Associates is the most-trusted provider of proven engineering services for the energy and process industries.”

Source: RevenueBase Database · checked Sep 22, 2026
6Indirect evidenceWesterville, OH, United StatesHQ checked Sep 22, 2026201-500228 contacts →

Indirect evidence

“In business since 1971, Electrical Reliability Services, Inc.”

Source: RevenueBase Database · checked Sep 22, 2026
7Indirect evidencePasadena, TX, United StatesHQ checked Sep 22, 2026501-1,000226 contacts →

Indirect evidence

“The TechCorr name is synonymous with safe, quality inspection services.”

Source: RevenueBase Database · checked Sep 22, 2026
8Partial evidenceTallmadge, OH, United StatesHQ checked Sep 22, 2026201-500195 contacts →

Partial evidence

“SDMyers is the industry leader in transformer and substation maintenance and electric power system reliability.”

Source: RevenueBase Database · checked Sep 22, 2026
9Partial evidenceCanonsburg, PA, United StatesHQ checked Sep 22, 2026201-500169 contacts →

Partial evidence

“Pennsylvania Transformer Technology LLC (PTT) is a US-owned, industry leading manufacturer of a wide range of sizes and types of power transformers for the investor-owned…”

Source: RevenueBase Database · checked Sep 22, 2026
10Partial evidenceSolomon, KS, United StatesHQ checked Sep 22, 2026501-1,000157 contacts →

Partial evidence

“Solomon Corporation buys, sells, repairs, recycles, and disposes of transformers, regulators and reclosers.”

Source: RevenueBase Database · checked Sep 22, 2026
11Partial evidenceIrvine, CA, United StatesHQ checked Sep 22, 202651-200153 contacts →

Partial evidence

“THE AUTOMOTIVE AFTERMARKET INDUSTRY LEADER Innova Electronics Corporation is a leading supplier of test equipment and diagnostic reporting for the automotive aftermarket, offering…”

Source: RevenueBase Database · checked Sep 22, 2026
12Partial evidenceVernon, CA, United StatesHQ checked Sep 22, 2026201-500147 contacts →

Partial evidence

“MGM Transformers is now part of Forgent Power Solutions.”

Source: RevenueBase Database · checked Sep 22, 2026
13Indirect evidenceOklahoma City, OK, United StatesHQ checked Sep 22, 2026201-500145 contacts →

Indirect evidence

“In 2025, Southwest Electric Co.”

Source: RevenueBase Database · checked Sep 22, 2026
14Partial evidenceMckinney, TX, United StatesHQ checked Sep 22, 2026201-500138 contacts →

Partial evidence

“Emerald Transformer is the premier national single-source solution for oil-filled electrical equipment with services including repair, re-manufacturing, field technical services…”

Source: RevenueBase Database · checked Sep 22, 2026
15Partial evidenceLake Mary, FL, United StatesHQ checked Sep 22, 2026201-500134 contacts →

Partial evidence

“At JST Power Equipment, we pride ourselves on delivering world-class transformer and electrical equipment solutions.”

Source: RevenueBase Database · checked Sep 22, 2026
16Indirect evidenceFort Worth, TX, United StatesHQ checked Sep 22, 2026201-50091 contacts →

Indirect evidence

“For over 25 years, Sentinel-TDS, based in Dallas/Ft.”

Source: RevenueBase Database · checked Sep 22, 2026
17Indirect evidenceHolbrook, MA, United StatesHQ checked Sep 22, 2026n/a91 contacts →

Indirect evidence

“Specialists in Electrical Power Systems - Testing, Commissioning, Maintenance.”

Source: RevenueBase Database · checked Sep 22, 2026
18Indirect evidenceBlairsville, PA, United StatesHQ checked Sep 22, 2026201-50090 contacts →

Indirect evidence

Source: RevenueBase Database · checked Sep 22, 2026
19Partial evidenceWaco, TX, United StatesHQ checked Sep 22, 202651-20086 contacts →

Partial evidence

“VanTran Transformers is now part of Forgent Power Solutions.”

Source: RevenueBase Database · checked Sep 22, 2026
20Indirect evidenceMassillon, OH, United StatesHQ checked Sep 22, 2026201-50066 contacts →

Indirect evidence

“Magnetech is an ISO-quality provider of electrical-mechanical industrial services, including testing, repair, rewind and refurbishment of ac/dc motors and generators…”

Source: RevenueBase Database · checked Sep 22, 2026
21Indirect evidenceConverse, TX, United StatesHQ checked Sep 22, 202651-20058 contacts →

Indirect evidence

“WELCOME Power Engineering Services is an Accredited, Full-Member of the International Electrical Testing Association (NETA), and a Registered Engineering Firm in 46 states.”

Source: RevenueBase Database · checked Sep 22, 2026
22Indirect evidenceLanham, MD, United StatesHQ checked Sep 22, 2026201-50057 contacts →

Indirect evidence

“ABM Electrical Power Solutions, LLC is an electrical power engineering, testing, and maintenance company based out of 4390 Parliament Pl, Lanham, Maryland, United States.”

Source: RevenueBase Database · checked Sep 22, 2026
23Partial evidenceFort Myers, FL, United StatesHQ checked Sep 22, 202611-5055 contacts →

Partial evidence

“Voltech provides innovative, reliable test equipment for the Power Electronics Industry, specializing in wound component and transformer testing.”

Source: RevenueBase Database · checked Sep 22, 2026
24Partial evidenceRichmond, IL, United StatesHQ checked Sep 22, 202651-20051 contacts →

Partial evidence

“75 Years of Engineering Excellence in the Delivered Worldwide Olsun Electrics is the industry’s most trusted partner for custom dry-type transformers.”

Source: RevenueBase Database · checked Sep 22, 2026
25Partial evidenceSacramento, CA, United StatesHQ checked Sep 22, 202651-20051 contacts →

Partial evidence

“TJ|H2b Analytical Services is a full service laboratory that offers analytical testing and diagnostic evaluation of oil and gas insulated electrical equipment at our global lab…”

Source: RevenueBase Database · checked Sep 22, 2026

Showing 25 of 285 transformer diagnostics companies based in the United States

See the full list, filter by size, metro and specialty, and get verified emails and direct dials for all 3,092 reachable decision-makers.

Free signup · no credit card

View the full list →

Transformer diagnostics companies based in the United States at a glance

As of Sep 22, 2026
38.4%Verified-email coverage
28.2Average contacts per company
11-50Median size (employees)
4.2%Largest-city concentration · Houston
Sep 22, 2026Page data refreshed

Companies by employee count

1-10
98
11-50
112
51-200
44
201-500
18
501-1,000
9
1,001-5,000
3

Email recency for this list is measured worldwide rather than for United States, so it is reported there. Company counts and contact totals on this page are exact for United States, over 285 companies.

How this list was built

Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among transformer diagnostics companies, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.

Source
The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
What qualifies
Companies headquartered in the United States whose own description of what they do matches “transformer diagnostics companies”. Matching reads each company's description, not its industry code or its name.
RevenueBase Smart Search
RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names transformer diagnostics companies), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
What we exclude
Companies whose own description does not clearly place them among transformer diagnostics companies, and records with no verified work email. Companies headquartered outside United States are excluded even when they keep an office there.
Match quality
In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
Ranking
Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
Verification
Every listed company carries at least one verified work email, 3,092 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
Refresh
This page's figures were pulled from the company graph on September 22, 2026. Lists refresh periodically as the graph is re-checked.
Corrections
Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.

Frequently asked

What is RevenueBase Smart Search?

RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names transformer diagnostics companies, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.

How many transformer diagnostics companies are there based in the United States?

RevenueBase identified 285 transformer diagnostics companies headquartered in the United States as of September 2026, matched on each company's own description of what it does rather than its industry code.

What is the largest company on this list?

Shermco Industries, headquartered in Irving, tops this list with the largest team on record.

Which city has the most transformer diagnostics companies?

Houston leads with 12 headquartered companies, followed by Atlanta (3) and Canton (3).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 3,092 verified decision-maker contacts tracked across these 285 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 22, 2026.

Ready to reach these companies? Verified emails and direct dials for all 285 transformer diagnostics companies based in the United States. Start with a free account, no credit card.

Download this list →

Related lists

About this data

RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.