If
a magnet is placed in the space between the coils, aligned
with the coil axis, and the meter is zeroed, then when the
magnet is withdrawn from the coil (regardless of the rate),
the fluxmeter indication is proportional to the magnetic moment
of the magnet. The magnet's magnetic moment may be defined
either as the average axial magnetic flux density in the magnet,
times its volume; or as the magnetic pole strength (an amount
of flux) times the magnetic pole spacing. The fluxmeter/Helmoltz
coil combination may be very fast, accurate and easy to use
for bar magnets, using proper equipment. With a suitable correction,
it may also be used for measuring arc segments. This method
will not work for magnets with multiple pole pairs, or for
ring mangets with radial magnetization, however. |