A level revision

Permeance

Permeance is the measure of the amount of flux for a given number of current-turns, it is given the symbol (lambda). Permeance, like conductance from AS, is related to both cross sectional area and length meaning a larger diameter iron core will yeild a greater permeance.

Permeance can be calculated in two ways, firstly there is the relationship between current-turns and flux:

Where is the current-turns

Alternatively there is an equation which is similar to that of conductance:

Where:
is the permeability of the material
is the cross sectional area
is the length

Permeance is given the units Webber per ampere-turn