Hi again.

I need to monitore two large reciprocating compressors (10 pistons) driven by a diesel engine (10 pistons). Neither have rolling bearings.

I think a good starting point would be the ISO 10816-1 (Evaluation of machine vibrations by measurements of non-rotating parts). Does anybody has experience in this kind of machines? What typical frequencies should be monitored?

This message has been edited. Last edited by: mechanical pawn,

Look over the maintenance history, failure records, rebuilds,materials used in rebuilds, MTBF and see what type failures you are having then develop a plan from there.

You may have a problem of rod deflection which can be monitored via eddy current probes. Some monitoring is going to be necessary and a correlation made operational parameters, failure history and type of measurements, possibly even perssure of the combustion chamber and strain measurements along with vibraton data.