About us

Le Cosinus: French Manufacturing Excellence at the Heart of Your Electrical Projects

For nearly 80 years, Constructions Electriques Le Cosinus has been much more than a simple electrical component manufacturer; we are a trusted technical partner, deeply rooted in the French industrial fabric. Founded in 1957 in Paris, our company has built a strong reputation as a specialist in the design and production of transformers, autotransformers, inductors and direct current power supplies. Our longevity is no accident: it reflects our resilience, our ability to weather economic cycles and adapt to technological developments, offering our customers a powerful signal of reliability and sustainability.

An Unwavering Commitment: Quality and French Manufacturing

Our brand identity rests on a fundamental pillar: an absolute commitment to quality, embodied by our slogan

"French manufacturing, a guarantee of trust".

As an agile and specialised SME, we stand out from mass producers through total control of our value chain. Every product that leaves our Île-de-France factory is the result of a rigorous process: 

Digital Precision

Our windings are produced on CNC winding machines, ensuring perfect geometry and flawless electrical performance.

High-Performance Impregnation

Our entire production is systematically varnish-impregnated under vacuum. This high-quality process eliminates air bubbles to guarantee perfect insulation, improved thermal dissipation and vibration-free operation, thereby significantly extending product lifespan.

Systematic Individual Testing

Where others test by sampling, we impose an iron discipline: 100% of our products are individually tested before dispatch on our own test benches. This gives you the ultimate guarantee of compliance and reliability for every unit delivered.

Your Technical Partner, from Standard to Custom

We believe our role goes beyond simply supplying products. We position ourselves as a true technical partner. Our value proposition begins well before manufacturing, with expert consulting and engineering services. Our specialists work with you to precisely define your requirements, whether related to voltage drop constraints, inrush current or electrostatic shielding.

This collaborative approach, combined with the flexibility of our structure, enables us to offer exceptional responsiveness: lead times of 24 to 48 hours for products in stock and one to two weeks on average for specific manufacturing. Whether you need a single-phase or three-phase transformer up to 800 kVA, a filter inductor or a stabilised power supply, our design office creates the solution perfectly suited to your application.

A Forward-Looking and International Vision

Our expertise, recognised in France, is successfully exported. We are proud of our ability to meet the most demanding international standards, including North American certifications (UL/CSA). This considerable technical and financial investment, which few European competitors undertake, is a strategic passport that opens the doors to the most demanding markets and demonstrates our international ambition.

Ideally positioned to address the challenges of the energy transition and the reshoring of supply chains, we are also committed on the environmental front. The use of solvent-free varnish reduces our ecological impact, and our compliance with the REACH directive demonstrates our sense of responsibility.

Choosing Le Cosinus means opting for deep technical expertise, uncompromising quality and the reliability of a historic, agile and resolutely forward-looking French industrial player.