F.W. Bell 7030, Instruction Manual

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F.W. BELL Model 7030 Gauss/Tesla Meter Instruction Manual
Section 3 - Probes 3-1
Section 3 Probes
OVERVIEW
F.W. Bell’s 7000 series gauss/tesla meter probes are designed to meet
the electrical and mechanical requirements of virtually any application.
Models are available for transverse, axial, 3-axis and very low field
measurements. The probe style is dependent upon the measurement
environment. The standard fiberglass stem is recommended for
laboratory or light handling environments, while the heavy duty aluminum
stem is recommended for harsher environments. The probe’s length,
outside diameter (axial probes) or thickness and width (transverse
probes) are important if there are physical constraints where the probe
will be used.
In “transverse” probes the Hall generator is mounted in a thin, flat stem
whereas in “axial” probes the Hall generator is mounted in a cylindrical
stem. The primary difference is the axis of measurement, as shown by
“+B” in
Figure 3-2 . Generally transverse probes are used to make
measurements between two magnetic poles such as those in audio
speakers, electric motors and imaging machines. Axial probes are often
used to measure the magnetic field along the axis of a coil or solenoid.
Either probe can be used where there are few physical space limitations,
such as in geomagnetic or electromagnetic interference surveys.
A 3-axis probe is a special configuration of three sensing elements
positioned orthogonally within a cylindrical stem. The instrument can
provide a separate reading for each axis as well as a vector sum of all
three axes.
The low field probe is designed for high sensitivity, volumetric
measurement such as mapping variations in the earth’s magnetic field or
detecting the presence of ferrous objects.
Handle Hall probes with care. Do not bend the stem or apply
pressure to the probe tip as damage may result.