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axis, and the meter is zeroed, then when the magnet is withdrawn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.