Magnetic flux density (Tesla)
The flux density (B) that sets the operating point of the core.
Definition
Magnetic flux density, denoted B and expressed in teslas (T), is the density of magnetic flux in the core, i.e. the flux divided by the cross-section: B = Φ / S. It characterises how hard the magnetic material is being driven.
Every magnetic steel has a saturation flux density (typically 1.5 to 1.8 T for silicon sheets). Designers choose a working flux density below this threshold: too low, and the core is oversized and costly; too high, and the iron losses and noise rise sharply while the risk of saturation increases.
The working flux density is therefore a central design trade-off, set according to the frequency, the type of lamination and the loss targets.
The ABL tip
A high working flux density reduces the size and cost of the transformer but increases heating and noise. ABL Transfo calculates the optimal flux density project by project, depending on whether you prioritise compactness, efficiency or quietness.
