Patent ID: 8547086

Claim:
A coercivity performance determination device for determining whether or not each part of a coercivity distribution magnet has a coercivity that is equal to or greater than a required coercivity, the coercivity performance determination device comprising at least: a substantially C-shaped magnetic body; excitation means that generates a magnetic flow in the magnetic body; and a flux meter that measures a residual magnetic flux of the coercivity distribution magnet, wherein protrusions are respectively provided at corresponding positions on two opposing end faces of the substantially C-shaped magnetic body, and the coercivity distribution magnet is held between the two protrusions to form an annular magnetic circuit comprising the substantially C-shaped magnetic body and the coercivity distribution magnet, external magnetic field generation means is formed by a magnetic region caused by the protrusions and a non-magnetic region comprising air in the periphery thereof, and a reverse magnetic field, which comprises the sum of an external magnetic field that is generated when magnetism generated by the excitation means flows through the protrusions forming the external magnetic field generation means and a demagnetizing field that the coercivity distribution magnet has, has the external magnetic field so adjusted as to correspond to the coercivity required of each part of the coercivity distribution magnet, and the residual magnetic flux when the coercivity required of each part of the coercivity distribution magnet has acted on the coercivity distribution magnet as the reverse magnetic field is measured with the flux meter to determine whether or not each part of the coercivity distribution magnet has the required coercivity.