AMH-DC-T-S | SOFT MAGNETIC MATERIALS
LABORATORIO ELETTROFISICO (RINGS)
IEC 60404-4, ASTM A773
AMH-DC-T-S Permeameter is an automatic DC measuring system to characterize toroid shaped
soft magnetic materials. Rings are the best shapes for such magnetic characterization: due to
the naturally closed magnetic circuit, the demagnetizing field inside the material is zero.
The sample must be wound with a primary set of NH turns for excitation. A secondary set of
NB turns must also be wound around the sample to record the magnetic flux. The H field is
determined measuring the current i in the primary winding: H = NH • i /l, where l is the length
of the magnetic path (i.e. the averaged ring circumference, when the ring O.D and I.D. are not
too different similar). The B field is determined measuring the magnetic flux ¥Õ from the secondary
winding: B = ¥Õ/(NB A), where A is the cross section of the specimen toroid.