Toroidal windings built to your drawing
We build toroidal transformers, autotransformers and inductors in Carate Brianza, Italy. One piece for the prototype, a few thousand for the run, always with the same testing.
Five winding families, one workshop
We do not keep a catalogue transformer that suits everyone. We start from the voltage you need, the power, the space you have in the machine, and build the part around those three constraints.
Toroidal isolation and safety transformers
The part we make most. It separates your electronics from the mains, brings the voltage down to what you need, and does it with very low no load losses and almost no stray field.
02Toroidal autotransformers
When galvanic separation is not required and only the voltage has to be adapted, an autotransformer does the same job in less space and with less copper. Typical for imported machines brought onto European mains.
03Inductors, line reactors and common mode chokes
Coils on ferrite, iron powder or nanocrystalline toroidal cores, to smooth a current, limit a rate of rise or take conducted noise off the line.
04Current transformers and sensors
High ratio windings for measuring a current without breaking the conductor. The primary is the busbar or cable that passes through the hole, the secondary is what we wind.
05Special coils and windings to order
Everything outside the four families above. Air coils, winding on cores you supply, rebuilding a part that is out of production, samples for laboratory work.
Useful numbers before you write to us
A workshop, not a catalogue
Toroidal Winding is a winding shop in Carate Brianza, in the middle of the Brianza district that has been building machines for sixty years. The person who answers the phone is the person who winds the part.
That changes two things. A doubt about the drawing gets settled in one call instead of three emails. And the awkward part, the one nobody wants because only twenty are needed, gets made here.
How a part comes together
Five steps, in the order they actually happen. The first and the last we do with you, the three in between stay in the workshop.
Specification
You send voltages, rating, maximum envelope and insulation class. If all you have is the old part to replace, that works too: we measure it here.
Calculation
We size the core, the turns count, the wire gauge and the layer build. You get back real rating, no load losses, estimated temperature rise and finished dimensions.
Winding
The wire is laid onto the closed core on a shuttle winder. Primary, shield if requested, then the secondaries, with insulating tape between layers.
Finishing
Impregnation, flying leads or faston terminations, part marking, potting or a containment cup where the application calls for it.
Testing and delivery
Electrical tests part by part, test report on request, packing and shipping. The batch number stays traceable.
Where our windings end up
The standard changes, the thermal class changes, the way the leads are terminated changes. The core stays the same trade.
Professional audio and high fidelity
The toroid was born here for a reason: almost no stray field and no mechanical hum passed to the chassis. We build supplies for power amplifiers, preamplifiers and studio racks.
Medical equipment
Here the separation between mains and patient is not a good idea, it is a requirement. We work to the manufacturer specification with double insulation and verified clearances.
Lighting and architectural
Supplies for extra low voltage luminaires, transformers for halogen lamps and for museum and outdoor lighting runs, where the envelope matters more than anything.
Automation and industrial panels
Control and isolation transformers for panels, line reactors for drives, common mode chokes to cut the noise inverters push back onto the supply.
Measurement, laboratory and test
Current transformers, reference windings, coils for test benches. Small quantities, tight tolerances, documentation required almost every time.
Power, charging and conversion
Filter inductors for converters, reactors for charging stations, isolation transformers for installations where separation from the mains is part of the safety case.
No part leaves without being powered up
Testing is not a separate service. It is the reason a toroidal transformer built here reaches the line and stays there.
- Dielectric strength between primary, secondaries and core
- Insulation resistance under direct voltage
- Turns ratio and open circuit voltage on every secondary
- No load current and inrush peak check
- Continuity and ohmic resistance of each winding
- Thermal test on the production sample under load
You have a drawing, an old part or just a voltage to reach
Send us what you have. If a figure is missing we will ask, and you get a quotation within two working days.