A transformer’s winding consists of insulated wire or foil conductors applied to the iron core. It is the electrically active component: this is where voltage is induced and current is carried. Its quality decisively determines service life, efficiency, and short-circuit strength. Designing and manufacturing the winding is one of the most demanding steps in transformer production and requires the utmost precision.
What types of windings are there?
Common types are layer windings, disc windings, and helical windings. Layer windings are commonly used in distribution transformers. Disc windings offer better voltage distribution in power transformers during impulse voltage events. Helical windings are frequently found in the low-voltage windings of large machines. Depending on the application, copper or aluminum is used.
Key Characteristics at a Glance
- Material: copper or aluminum
- Types: layer, disc, or helical winding
- Insulation made of a paper-oil system or epoxy resin
- High mechanical strength against short-circuit forces
- Precision manufacturing as a prerequisite for a long service life
- Copper conductors are paper-wrapped in large machines
- Flat conductors, round wire, or foils depending on the application
Frequently Asked Questions
Why must windings be short-circuit-proof?
During a short circuit, extreme axial and radial forces occur that could mechanically deform the windings. A short-circuit-proof design – with precision manufacturing, stable support structures, and correct clamping – prevents such damage and ensures longevity.
What influence does the winding have on losses?
The resistive losses in the winding (load losses or short-circuit losses) are, after no-load losses, the second-largest loss component of a transformer. High-quality materials and well-thought-out winding geometries reduce these losses – and therefore energy consumption over decades.
What trends exist in winding technologies?
Foil windings made of aluminum or copper are increasingly becoming established in distribution transformers. They are particularly short-circuit-proof, mechanically stable, and enable compact designs. For high-voltage windings, higher-grade insulating papers and oil-resistant materials are also being used.
How is the winding protected against moisture ingress?
In oil-type transformers, the oil, together with drying systems, protects the winding. In dry-type transformers, coatings and hydrophobic finishes are used. Cast-resin windings are completely encapsulated by the resin. Residual moisture is measured before every commissioning, since moisture would significantly reduce service life.
For custom transformers with optimized winding design, we will develop the right solution together with you. Contact our experts.