we have ms9001 e gas turbine controlled by markv tmr. trip generator in sequence start up tnh = 2375tr/min a cause high vibration proximator 39vghh bearing 5!!!!<pre>
when vibration smique
39v4,,,,,6.51 mm/rms
39v5,,,,,3.3
39v6 8.45

and vibration proximtors
39vs42 275um pp
39vs41 189 um pp</pre>

 

There's too little information to provide any assistance.

It's <b>extremely</b> rare that vibration excursions happen without any previous event, such as an emergency trip from load or a maintenance outage (combustion inspection, hot gas path inspection, major inspection, generator inspection, etc.). Another possible cause could be recent work in the collector compartment where someone has "disturbed" the vibration sensors (seismic or proximity).

So, when did this problem occur--after what event: maintenance outage, trip from load, work in the area of or on the vibration sensors?

2375 RPM is approximately 80% TNH, and about the only thing that should be happening at that speed during start-up and acceleration is the IGVs should be starting to open. But they're at the complete opposite end of the machine so that shouldn't be the cause of the problem.

Does field flashing occur on your machine at some speed other than approximately 95% TNH?

It's not uncommon for there to be discrepancies between seismic and proximity vibration sensor. Usually though, the proximity readings are more accurate, presuming the proximity probes are good, the gap voltage is correct, the proximitors are good, the wiring is good, and the sensor (B-N monitor, usually) is good.

 

Ge Frame 9001E
I Am working on frame 9001E controlled by bently Nevada 3500. can i have more information about high vibration in the Turbines :

1* during the start up followed by a forced shutdown ..

2* vibration period sympathetic with rpm.

3* VIBRATION PROXIMETOR BEARING N5 GENERATOR