Both work, both reach Tier 2, and both equip transformers all across Europe. So the debate is not "which is good", but what each costs in volume, weight and lifetime. Here is the comparison, without dogma.
The heart of it is one number: copper conducts better than aluminium (about 1.6× for equal cross-section). To carry the same current with the same losses, an aluminium winding must be larger. Everything else, size, weight, price, connection design, follows from that. Neither is "bad": they are two different trade-offs.
| Criterion | Copper | Aluminium |
|---|---|---|
| Conductivity | Higher (~1.6× for equal section) | Lower: bulkier winding for equal losses |
| Footprint | More compact at equal performance | Bulkier |
| Weight | Heavier (dense copper) | Lighter |
| Material cost | More expensive | Cheaper |
| Connections | Stable at terminals, low maintenance | Need particular care (creep, oxidation) at the joint |
| Mechanical strength (short circuit) | Robust | Adequate if well designed |
| Lifetime | Reputed very durable, especially at connections | Reliable if well designed and correctly connected |
| Tier 2 compliance | Achievable | Achievable (winding sized accordingly) |
Aluminium is not a "lesser copper": it is a legitimate choice when weight or budget dominate and the extra bulk is acceptable. Well designed and correctly connected, an aluminium winding does its job perfectly. Its watch-point remains the quality of the connections: that is where yesterday's poor workmanship gave aluminium a sometimes unfair reputation. With careful design, it is no longer an issue.
The right choice depends on your priority: compactness and longevity (copper), or weight and budget (aluminium). State your preference in the configurator, or let us steer you by application.
General guidance; the exact winding design is confirmed case by case according to power, target losses and project constraints.
Neither is "better" in the abstract. Copper is more conductive, more compact and reputed to last longer, especially at connections; aluminium is cheaper and lighter, but the winding is bulkier for equal performance. Both reach Tier 2.
Yes, a properly designed and correctly connected aluminium winding is reliable and widely used. The historic watch-point is the connection (creep, oxidation): it needs particular care. Done well, aluminium is a legitimate choice, especially when weight or budget dominate.
By default we favour copper, for its compactness and durability, particularly at the terminals. Aluminium remains available on request when weight or cost justify it. The choice is made case by case in the configurator.
The conductor choice crosses with the core, the type and efficiency.
Tell us your priority (compactness, weight, budget): we size the winding accordingly, first reply within 48 h.
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