Transformers

Le Cosinus has been a recognised specialist manufacturer of electrical transformers for over 80 years. We manufacture all our low-voltage, Ecodesign, medical and standard transformers at our site in Ozoir-la-Ferrière, in the Île-de-France region.

Whether single-phase transformers, three-phase transformers or three-phase-single-phase transformers, you will find our entire catalog of standard products offered for sale online on these pages.

You can also contact us for any requests for customised transformers or transformers adapted to your needs. Le Cosinus can meet all your needs, whether standard or specific.

Single-phase transformers

Single-phase isolation transformers are typically used in low-power installations or inside electrical cabinets, thanks to their high electrical insulation capacity, which separates networks to secure installations, equipment and users.

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Three-phase transformers

Three-phase isolation transformers are typically used in high and very high power installations within industrial environments. With substantial galvanic isolation, generally 3,000 Volts minimum, they play a key role in separating electrical networks.

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Three-phase to single-phase transformers

Three-phase to single-phase transformers, commonly referred to as "tri-mono", convert a three-phase network into a single-phase network while ensuring better load distribution across the three-phase network than a simple phase-to-neutral connection.

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Medium-voltage

Three-phase medium voltage oil-immersed transformers

Three-phase medium voltage oil-immersed transformers use ONAN (Oil Natural Air Natural) cooling. This means these transformers use oil to extract heat from the transformer core and dissipate it naturally into the air, without the assistance of fans.

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Three-phase medium voltage dry-type transformers

Three-phase medium voltage dry-type transformers are typically used in high and very high power installations. Voltages range from a few kilovolts to a few tens of kilovolts in industrial environments.

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Other Transformers

Ignition transformers

Ignition transformers are specialised transformers designed to generate high voltages. Voltages typically range from 5,000V to 10,000V, in order to create an electric arc to ignite a gas or oil boiler. This works on the same principle as a spark plug in petrol engines.

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In particular, we can add electrical protection (circuit breakers, disconnectors, fuses), adapt input and output voltages, add an electrostatic screen or adjustment Taps, adapt the transformer to harmonics, phase angle or pulse width modulation dimmer, multiply secondary voltages, perform any type of coupling, supply silent blocks or swivel castors, adapt dimensions, colours and protection ratings of enclosures, supply input and output cables, and much more.

All our transformers are, by definition, isolation transformers, systematically complying with international standards (IEC) and, upon request, with the UL/CSA insulation standard.

Note: if you are looking for a Le Cosinus product that is not listed in the standards offered on the website, you can find it directly using the search engine. If it is listed, you can obtain information about it or request a quote from us.

If you cannot find your product among the 10,000 references on this site, please contact us directly. It may be a very old product, but we are able to reproduce products even if they were manufactured many years ago.

Today's standard voltages are 230 V single-phase and 400 V three-phase. Many people still use 220 V and 380 V voltages out of habit. Our products, with 400 V and 230 V voltages, will easily adapt to older voltages. They will only work better!