Vibration Probes

I think I know what you are asking but am not positive, I am not sure if I understand the question fully. Did my answer to your prior post this morning, Keyphasor and Eccentricity Probe help or did I not understand your prior question fully? Are these two questions related? Was your prior question about turbines too? Let me know and I will try and assist.

Yes there is but the answer is a multiple complex answer. Vibration analyses requires specialized equipment and experience. Common techniques examine the individual frequencies present in the signal regardless of gas, steam, coal, hydro, etcetera. Frequencies correspond to certain mechanical components like a shaft bearing and then would match to certain malfunctions like a shaft misalignment. The equipment will show harmonics and frequencies so you can identify the component and likely problem, most of the time, or sometimes – that is why it is complex. Sometimes there is no warning and the machine breaks and sometimes there are too many things wrong and it is hard to determine one specific cause. Just like a bearing failing will increasingly cause higher harmonics and more vibration, so will a number of other problems. The reason some types of probes are used on some types of turbines is because those are better suited for the driving force and for the specific turbine. Sometimes I have seen manufacturers recommend what type of equipment to use for monitoring.

ACTUALLY I AM NOT SURE BUT NORMALLY USED BITH TYPE OF VIBRATION PROBE USED IN GAS TURBINE VELOCITY AS WELL AS PROXIMATERY SWITCH.NORMALLY GAS TURBINE PROTECTION GIVEN ON VELOCITY PROBE & FOR MEASURMENT O=& OBSERVATION OF SHSFT BEHAVE DISTANCE VIBRATION (PROXIMATRY ) PROVIDED. ONE MAY BE REASON OF INTERNAL COMBUSTION OF MACHINE. BUT IN STEAM TURBINE NORMALLY DISTANCE VIBRATION PROBE USED FOR PROTECTION ALSO.

ONE MORE THING KEY PHASER IS THE DIFFERENT MATTER. IT IS USED FOR TO MEASURE THE SPEED OF THE SHAFT WHICH IS INSTALLED ON SHAFT & SPEED PROBE INSTALLED ON THE STATIONARY PART BY CUTTING OF EDGE DISTANCE PROBE CAN MEASURE THE TEETH & THAT CAN CONVERT TO SPEED PROFILE

Normally I think both seismic and proximity probes X and Y are both have trip voting system or machine protection system. The deferent is the seismic probe receiving the measurement by MM and the main specification of seismic is to detect the high vibration which is located on the gearbox and bearings housing only means overall vibration. Proximity probes its very good probes design to give us and show us data about shaft behavior, shaft centerline position, eccentricity, shaft motion, alignment between shafts. The proximity probes as well read the vibration data by um p-p or mils for the shaft movement in side bearing clearance if the clearance get more bigger or white metal defect will generate more movement thus lead the machine to get high vibration and lead to trip. Finally both are have same specification for machine trip who is getting higher value will be first to trip.

Proximity probes show shaft movement relative to the bearing. The seismic probes show bearing housing movement.

Many companies do not trip machines on radial vibration as a spurious trip can be very expensive and they rely on the operator to intervene when alarms go off.

For gas turbines (internal combustion engines) the failures can be very quick and without warning, so they use a simple "seismic" probe (usually reading velocity) to trip the machine in case of catastrophic failure, which happens too quickluy to allow for operator intervention. The purpose is to try to keep the rotor inside the casing.