After our first article on transformer cores, we are here with our second article on transformer coils. In this article, we will talk about the effects of Eco Design Directive losses on coil design and production.

In general, we can say that the core cross-sections (diameters) will increase due to the reduced no-load losses in transformers. We can say that the coil heights will increase in order to tolerate the short circuit impedance, which tends to increase with increasing core diameters.

In addition, the cross-sections of the wires used in the coils will definitely increase compared to the past due to the lower load losses. We can easily say that the use of parallel wires will also increase.

In summary, we can list the changes that will occur in the coils as follows:

• Sections will increase in both LV and HV coils. Wire suppliers and transformer manufacturers should arrange their production and stock levels accodingly.
• Flat wire usage will increase comparing with round wire usage. Winding machine capabilities should change according to more flat wire usage.
• Parallel wire usage (axial or parallel) will increase. Winding machine capabilities should change accordingly.
• Coil heights will increase – machine mandrel lengths should be increased.
• Busbar dimensions will change.
• Labor cost will increase for coil production.
• Foil limits will change. Foil suppliers and transformer manufacturers should arrange their production and stock levels accodingly.
• Parallel foil usage will increase (both radial and axial). Winding machine capabilities should change accordingly.
• Coil weights ( material consumption) will increase.

Our third article will be published soon!