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Decades of Experience

Take a look at our company milestones


International Transformers

International Transformers, was founded by Ernest Lee in the 1930s and became one of the main UK specialist manufacturers within the industry. With a world-wide range of well-known customers including the Ministry of Defence (MOD), British Aerospace, Alstom, UKAEA/BNFL, BP and others.



Stewart Transformers

Stewart Transformers began as a small operation supplying transformers to the London radio repair sector, just prior to the second world war. During the war the still fledgling company was called upon, as part of the war effort, to supply transformers to the naval arm of the Ministry of Defence, starting a relationship which was set to continue and strengthen for decades.

Over the years the Company developed a sound reputation as a specialist manufacturer of transformers and reactors. The company has also expanded from its traditional markets of railways, shipbuilding, defence, semiconductor and high voltage testing to embrace requirements for the utility industries.

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Transtech Transformers

Transtech Transformers was founded in the mid-1970's, as part of a group of companies supplying high volume, custom-built transformers. Transtech developed a range of transformers from 1VA single phase to 100kVA three phase, double wound with voltages up to 650 Volts, including toroidally wound components, ferrite assemblies and resin encapsulated units.  Transtech also developed a range of battery chargers, principally for the refrigeration, mobility and leisure industries.


 iST Power

In 2007 the three companies merged into one entity, known as 'IST Power Ltd'. We rationalised our production capabilities and facilities into two focused factories with a clear strategy and supporting investment for each. Our Leicester factory focuses on dry and resin cast transformers, reactors and other wound components. Our Manchester factory is focused on liquid immersed transformers & reactors.

We are a market leader in the supply of HV DC isolation transformers, earthing auxiliary transformers, auxiliary transformers & MOD shock rated auxiliary transformers.

We are committed to offering innovative products that meet customer expectations and the development of our people is critical in ensuring this is achieved!

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