Does anyone have a procedure for setting the thrust probes on a GE gas turbine? I have a difficult customer that wants me to provide documentation.

By trade I am a mechanical guy. I have been around many Bently Techs and Controls Techs. Each has there own flavor for setting them. I have never seen a written procedure in my 26 years in this industry. (This could be because I am a mechanical guy!)

Best Regards,
Jason Hampton

 

A written procedure? For something to do with adjustment/calibration of a device providing indication to a Speedtronic turbine control system?

Surely you jest!

And, difficult customers?

Again, surely you jest!

If I recall correctly, setting thrust probes involves "bumping" the rotor against the active thrust face and adjusting the gap voltage if necessary, setting a measuring device to zero (such as a dial indicator), then "bumping" the rotor against the inactive face, measuring the distance traveled, then setting the probe sensitivity.

This does require having the Mechanical Department's assistance with a hydraulic jack of sufficient size and placement to "bump" the rotor in both directions. Sometimes, this took longer (finding suitably strong places to jack against) than the rest of the procedure.

It's been many years since I was part of a group of people getting OJT on this topic (in other words, we figgered out how to do it in the absence of any documentation or on-site knowledge). But, I would point the (difficult) Customer to the thrust probe manufacturer's documentation and then follow that procedure. If memory serves correctly, that's basically what we did.

 

Hi Jason,

I do have a procedure that was written by a controls TA.

It is for a 9E and also from what I recall it wasn't totally correct. It may be a good basis to start on though.

Let me know if you would like me to send it.

Regards
M

 

by checking the floatation of the rotor on the either side, we can set the thrust probe gap. First of all Mechanical people measure the total floatation, which is in "Thou".

Suppose if the total Floatation of the rotor is 10 Thou, they make it center. That means at "0" Thou, we instrument people have to adjust the thrust probe gap voltage as -9.5V.

Take the rotor one side. That means at 5 thou adjust the gap voltage as -9.5 V+ (-1 V)= -10.v.

Now take the rotor other side, That means at 5 thou, adjust the probe gap voltage as -9.5V- (-1V)= -8.5 V.

This is the procedure for the Thrust probes gas voltage adjustment.

Regards,
R.Jagan Mohan Rao
Kuwait