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Material, dimensions, and profile of target |
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| Change in output characteristics due to material |
| GAP-SENSOR works as long as the target is metallic. Note that both thesensitivity and the measuring range are dependent on the material of thetarget. |
| Dimensions of target |
| It is recommended that the relative surface area of the target should be atleast twice as large as that of the sensor coil. When the surface area ofthe target is less than this size, the sensitivity is decreased. If the target ispowder, laminated material (when measured at its cross section), or awire bundle, the sensitivity is decreased as well, and at worst themeasurement may be impossible. |
| Thickness of target (In the case of PU-05) |
| When the thickness of the target is more than 0.2mm
(irem SCM440), 0.4mm(Alminum A5052P), 0.3mm (copper C1100P) the sensitivity
is not affected by the thickness. |
| Profile of target |
| When the target is cylindrical (e.g., shaft) and its diameter is at least 3.5times as large as the sensor coil, the sensitivity is not affected by the profile of the target. Should this ratio be one to one, the sensitivity isdecreased to about 70 %. |
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| Run-out phenomenon |
In the measurement of axis vibrations,
the output that does not correspond to true value may be observed.
This event iscalled " run-out phenomenon". The mechanical
run-out attributable to scratches, unevenness and elliptical or eccentricsurfaces
can be prevented by corrective machining. For the electrical run-out
observed in the measurement of axis vibrations on magnetic substances,
particularly steelproducts, the causes are not simple, and it has
been considered that electrical run-out is caused by the remainingmagnetism,
uneven crystalline structure, and dispersed surface quench hardness
of the steel material. Differentcountermeasures as shown below may
be needed depending on the measurement objective.
a. Demagnetizing
the target axis after machining.
b. Lining copper sheet around the
target axis and machining the target axis.
c. Decreasing the compressive
stress from the target axis.
d. Changing the target from steel to
copper or any other appropriate material. |
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