[Rafe Britton]

Hi @sergey.manevitch, great question! Yes, I should clarify. When I said that Fe (ppm) isn’t important, I meant the absolute value. Let’s say you have 100 ppm. Is that high? Low? It varies by OEM and application type. Now say 500 hours later, the value is still 100 ppm. That’s good! This means there are no additional wear metals that have been generated in the application.

By contrast, I could have a value of 80 ppm, which is less. But if 200 hours ago the value was 10 ppm, than this unit is wearing at a significantly faster rate.

That’s really what I meant – we should be focussing on the rate of change of the number, rather than the absolute value.