APR (automatic Recordig Permeameters) use a closed loop
form of magnetic measurement. Due to the fact Permeameters use
pieces in the process the field is limited to approx. 2.4 Tesla.
As the sample must be in good contact with the pole
pieces, the shape and size of samples to be measured is limited to
simple shapes such as cylinders.
It is typical to use an Integrating Fluxmeter for
detecting sample’s magnetisation in the Permeameter system. This
pose a problem, as the applied field must be dynamic so the Integrating
Fluxmeter can detect it.
If the rate of change of the applied field is too high,
eddy currents will be induced in the sample and even worse in the
highly conductive pole pieces. If the rate of change is too slow,
Fluxmeter may drift and this could affect the measurement signal.
It is therefore important to have Integrating Fluxmeters
with a very good drift performance for use in the Permeameter.