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Appendix
Reference Materials
1. Measuring Principle
The measuring principle of the magnetic balance electromagnetic
induction method is shown in the illustration below, the magnetic
circuit sensor is composed of an exciter coil connected to the both
sides of the detection coil, the magnetic field generated by both
exciter coils are blanketed in the vicinity of the center detection coil.
Normally, the center detection coil does not generate an induction
voltage, on the other hand when the sampled grease containing iron
particles is inserted into the exciter coil, the magnetic field is offset
by the magnetic permeability variation, and an induction voltage is
generated in the detection coil. The induction voltage can measure
the concentration of the iron particles in the sampled grease.
Amplifier
circuit
Transmission
circuit
Sampled grease
Exciter coil 1
Detection coil 2
Exciter coil 2
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