Active and Passive Speed Probes and their Gapping?

U should see API-670

Thank you very much. I've found one and it has all that I want to know.

The one I found is : Machinery Protection Systems

API 670 FOURTH EDITION, DECEMBER 2000

So I'd like to know, Is it worth studying or it has become obslete and a newer has come?

Thanks!

Edition does not matter but the contents. When new edition comes few things were changed rest were remained same. So its worth studying for your instrumentation related quries

Dear Usman,

Could you please tell me where I can see the part where Gapping of speed probes is desribed in API-670.Though it's has detailed information about Active and Passive type with their application, I can't seem to find the anything related to Gapping. Please Help me.

Thank you.

The gap depends upon many factors like

pole diameter

Gear pitch

Target Material

Usually this gap is given in manual of the probe which you are using