What is the permeance coefficient and how it is used in magnetic design?
In its broadest sense, the permeance coefficient is a figure of merit for a magnet, or magnetic circuit, which indicates the ease with which flux travels from the North Pole to the South Pole (of course, magnetic flux does not actually travel, or flow. However, it is conceptually beneficial to describe the system in this manner). After magnetization, a magnet, or magnetic circuit, will operate at some point on the demagnetization curve for that magnet. Certain shapes of magnetic circuit will operate lower down on the demagnetization curve than others. The permeance coefficient, calculated by using values based purely on the geometrical parameters of the magnetic circuit, allows the magnetic design engineer to determine this operating point of the magnet on the demagnetization curve. A good example to indicate the qualitative difference between magnets of low and high permeance coefficient would be to consider a long, pencil shaped magnet (magnetized through its length) and a flat, coin
