Reluctance.
In a magnetic circuit or portion thereof, the resistance offered to the
flow of lines of force. The magnetic circuit as has already been stated
is treated like an electric circuit, and in it reluctance occupies the
place of resistance in the electric circuit. It is the reciprocal of
permeance. S. P. Thompson expresses the law thus:
Total number of magnetic lines = (magneto-motive force) / (magnetic
reluctance)
Synonyms--Magnetic Reluctance-Magnetic Resistance.
Reluctance, Unit of.
The reluctance of a circuit through which unit magnetizing power
(magneto-motive force) can produce a unit of induction or one line of
force. This value is very high; the reluctance of ordinary magnetic
circuits ranges from 1E-5 to 1E-8 unit of reluctance.
Reluctivity.
Specific reluctance; the reluctance of a cube of material whose edge
measures one centimeter in length. It is a quality bearing the same
relation to reluctance that permeability does to permeance.
It is defined as the reciprocal of magnetic permeability. (Kenelly.) If
plotted as a curve for different values of the magnetizing force it is
found to be nearly a straight line, a linear function of the magnetizing
force, H with the equation a + b H. Reluctivity is the property of a
substance; reluctance is the property of a circuit.