Why Different LVDT Cores can Give Different Non-Linearity & Sensitivity Results
Considering replacing an LVDT core?
LVDT cores are not always interchangeable without resulting in changes to the LVDT's non-linearity and sensitivity.
Listed below are the primary reasons for variation between LVDT cores:
- Variations in core length and diameter
- Variations in hi-perm alloy chemistry
- Variation in material homogeneity
- Variations in the annealing process
If cores are from same lot of material and annealing, variations in sensitivity and non-linearity are typically less than 0.1 to 0.2 %. Chances are that the core you are using as replacement would not meet this criteria.
Also of note, cores must not be subjected to work hardening actions or their magnetic properties can be affected and cause larger variations.
Best practice after replacing the LVDT core is to recalibrate the LVDT either in situ or on a certified test stand.