Patent ID: 6201386
Filing Date: 2001-03-13
Classification: G01R

Abstract:
A high speed method of characterizing high coercivity permanent magnets for high throughput production testing of the same, said method comprising:(a) providing a fully magnetized high coercivity magnet for testing;(b) subjecting said fully magnetized high coercivity magnet to a progressively changing magnetic field such as progressively to demagnetize the magnet;(c) monitoring the state of magnetization of the magnet during the progressive demagnetization step;(d) monitoring the strength of said progressively changing magnetic field during said progressive demagnetization step;(e) noting the strength of said progressively changing magnetic field when the magnetization of the magnet is reduced to zero; and(f) deriving from said noted strength an indication of the coercivity of the magnet;wherein the progressive demagnetization of the magnet around its hysteresis curve is not recorded.