Eddy currents
The currents induced in the core, limited by the lamination of the sheets.
Definition
Eddy currents are induced electrical currents that loop within the magnetic core itself, under the effect of the varying flux. Like any current flowing through a resistance, they dissipate heat and make up a significant part of the iron losses.
To limit them, the core is never solid: it is laminated, i.e. made of thin sheets insulated from one another by a varnish. This lamination breaks the large current loops into many small low-energy loops, drastically reducing the losses. The thinner the sheets, the lower the eddy-current losses.
This is one of the reasons why the quality and thickness of the sheets are decisive.
The ABL tip
Lamination and inter-sheet insulation make all the difference to losses. ABL Transfo uses thin, quality insulated sheets to minimise eddy currents, especially on efficiency-critical applications.
