Company lists · Data refreshed September 2026
Top 25 Isolation transformer manufacturers based in the United States
RevenueBase identified 69 isolation transformer manufacturers headquartered in the United States as of September 2026 and tracks 1,504 professional contacts across them, including 367 with verified work emails. Addison is the largest hub.
This list covers isolation transformer manufacturers 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 30, 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.
The 25 largest isolation transformer manufacturers based in the United States
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 202 contacts → | ||||
Strong evidence “HD Hyundai Power Transformers USA, Inc, a subsidiary of HD Hyundai Electric Systems, stands as a premier transformer manufacturer located in Montgomery, Alabama.” Source: RevenueBase Database · checked Sep 30, 2026Thanks. The Data Team will review it. | |||||
| 2 | 177 contacts → | ||||
Indirect evidence “NWL Inc.” Source: RevenueBase Database · checked Sep 30, 2026Thanks. The Data Team will review it. | |||||
| 3 | 169 contacts → | ||||
Strong 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 30, 2026Thanks. The Data Team will review it. | |||||
| 4 | 147 contacts → | ||||
Partial evidence “MGM Transformers is now part of Forgent Power Solutions.” Source: RevenueBase Database · checked Sep 30, 2026Thanks. The Data Team will review it. | |||||
| 5 | 86 contacts → | ||||
Partial evidence “VanTran Transformers is now part of Forgent Power Solutions.” Source: RevenueBase Database · checked Sep 30, 2026Thanks. The Data Team will review it. | |||||
| 6 | 51 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 30, 2026Thanks. The Data Team will review it. | |||||
| 7 | 46 contacts → | ||||
Strong evidence “Founded in 1973, Neeltran is uniquely positioned as one of the few companies in the world that designs and manufactures its own rectifier-transformers and rectifiers in the same…” Source: RevenueBase Database · checked Sep 30, 2026Thanks. The Data Team will review it. | |||||
| 8 | 32 contacts → | ||||
Strong evidence “ITEC, a MacLean Power Systems (MPS) company, specializes in the design and manufacture of dry and oil-filled transformers, ensuring the safety and reliability of electrical…” Source: RevenueBase Database · checked Sep 30, 2026Thanks. The Data Team will review it. | |||||
| 9 | 31 contacts → | ||||
Partial evidence “For over 40 years, Micron has been the supplier of choice for original equipment manufacturers and control system builders around the world.” Source: RevenueBase Database · checked Sep 30, 2026Thanks. The Data Team will review it. | |||||
| 10 | 31 contacts → | ||||
Strong evidence “Vanguard Electronics has been an industry leader for over 60 years in the design and manufacture of inductors and transformers.” Source: RevenueBase Database · checked Sep 30, 2026Thanks. The Data Team will review it. | |||||
| 11 | 28 contacts → | ||||
Partial evidence “Jefferson Electric delivers precision-engineered transformer solutions trusted across industrial, commercial, and utility markets.” Source: RevenueBase Database · checked Sep 30, 2026Thanks. The Data Team will review it. | |||||
| 12 | 27 contacts → | ||||
Partial evidence “Since 1981, Pacific Transformer has remained a market leader in the field of custom transformers, magnetic engineering, and power transformer design.” Source: RevenueBase Database · checked Sep 30, 2026Thanks. The Data Team will review it. | |||||
| 13 | 27 contacts → | ||||
Strong evidence “For over 40 years, Toroid Corporation has been a leading provider of custom-designed toroidal transformers and medical isolation transformers, proudly made in the USA.” Source: RevenueBase Database · checked Sep 30, 2026Thanks. The Data Team will review it. | |||||
| 14 | 20 contacts → | ||||
Indirect evidence “Warner Power is now part of Grand Power Systems!” Source: RevenueBase Database · checked Sep 30, 2026Thanks. The Data Team will review it. | |||||
| 15 | 16 contacts → | ||||
Partial evidence “Norlake Manufacturing Company | Engineered transformers and custom transformer solutions for over 50 years.” Source: RevenueBase Database · checked Sep 30, 2026Thanks. The Data Team will review it. | |||||
| 16 | 13 contacts → | ||||
Partial evidence “MAKING THE FIRST CHOICE AN EASY CHOICE Acutran dry-type transformers are available in multiple designs.” Source: RevenueBase Database · checked Sep 30, 2026Thanks. The Data Team will review it. | |||||
| 17 | 12 contacts → | ||||
Strong evidence “BLOCK – perfecting power BLOCK is a leading manufacturer of transformers, power supplies, electronic circuit breakers, reactors and EMI filters.” Source: RevenueBase Database · checked Sep 30, 2026Thanks. The Data Team will review it. | |||||
| 18 | 11 contacts → | ||||
Indirect evidence “At D Volt Co, we help accelerate the infrastructure behind AI and next-generation data centers.” Source: RevenueBase Database · checked Sep 30, 2026Thanks. The Data Team will review it. | |||||
| 19 | 11 contacts → | ||||
Strong evidence “Custom transformer design and manufacture” Source: RevenueBase Database · checked Sep 30, 2026Thanks. The Data Team will review it. | |||||
| 20 | 8 contacts → | ||||
Indirect evidence Source: RevenueBase Database · checked Sep 30, 2026Thanks. The Data Team will review it. | |||||
| 21 | 7 contacts → | ||||
Indirect evidence Source: RevenueBase Database · checked Sep 30, 2026Thanks. The Data Team will review it. | |||||
| 22 | 4 contacts → | ||||
Indirect evidence Source: RevenueBase Database · checked Sep 30, 2026Thanks. The Data Team will review it. | |||||
| 23 | 4 contacts → | ||||
Indirect evidence “As the Flagship of Custom magnetics, Ensign has come a long way since 1939.” Source: RevenueBase Database · checked Sep 30, 2026Thanks. The Data Team will review it. | |||||
| 24 | 3 contacts → | ||||
Partial evidence “Amgis Toroidal Power Products is now offering an extensive line of toroidal power transformers and products, including off the shelf products and custom designed toroidal…” Source: RevenueBase Database · checked Sep 30, 2026Thanks. The Data Team will review it. | |||||
| 25 | 2 contacts → | ||||
Strong evidence “Shape LLC is a leading designer and manufacturer of custom electrical transformers.” Source: RevenueBase Database · checked Sep 30, 2026Thanks. The Data Team will review it. | |||||
RevenueBase Smart Search
RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: isolation transformer manufacturers. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.
- Strong evidence
- The company's own public description of its business names isolation transformer manufacturers.
- Partial evidence
- Its own public description names part of isolation transformer manufacturers, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name isolation transformer manufacturers. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.
RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.
Showing 25 of 69 isolation transformer manufacturers based in the United States
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Isolation transformer manufacturers based in the United States at a glance
As of Sep 30, 2026Companies by employee count
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 69 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 isolation transformer manufacturers, 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 “isolation transformer manufacturers”. 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 isolation transformer manufacturers), 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 isolation transformer manufacturers, 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, 367 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 30, 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 isolation transformer manufacturers, 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 isolation transformer manufacturers are there based in the United States?
RevenueBase identified 69 isolation transformer manufacturers 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?
HD Hyundai Power Transformers Usa, INC, headquartered in Montgomery, tops this list with the largest team on record.
Which city has the most isolation transformer manufacturers?
Addison leads with 3 headquartered companies, followed by Grand Haven (3) and Cincinnati (2).
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 367 verified decision-maker contacts tracked across these 69 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 30, 2026.
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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.
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