Hi all

we have a problem with the fuel servo current "FAL" at start-up which should be more then 27% but it is fluctuating between 25% and 28%. Therefore we can't start the turbine.

we verified the wiring for earth, changed the Moog, even the TBCI but nothing changes.

Could you help plz

 

Hi,

FAL is the Liquid Fuel control servo output current.

You haven't told us what fuel you are trying to start with, what version of Speedtronic the turbine has, and what alarms (Process- <b>AND</b> Diagnostic!) are being annunciated when you are unable to start the turbine.

Also, you haven't told us when the problem started (MOST important).

If this is a problem when the turbine is at zero speed, and the Control Constant is preventing you from re-setting the alarm and getting a "Ready to Start" then it's even more important to get as much information as possible. If the unit is operating on Liquid Fuel or can't start because of this liquid fuel condition it's important to know if there is any liquid fuel flow feedback at zero speed which could be causing this problem.

Please also tell us what Frame size machine you are working on.

A Mark VI or Mark VIe TBCI has nothing to do with servo-valve outputs.

 

CSA thank you for your reply.

we have GE frame6 with Mark 6 and we start the machine with diesel.
The problem is that at stand still the "FQROUTTV1" bloc compare the "FAL" to 27% constant and if FAL<27% the L3LFLT (liquid fuel control fault) output is active which inhibit the starting of the machine or during start up causes a pre-ignition trip.

Sometimes the fault is active before start-up so we couldn't start and sometimes it occurs during start-up then we trip.

By the way TBCI was a mistype I mean I changed the TSVO.

Thanks for your help

 

MIKEVI:

We have two MS7EA turbine with MARKVI(same problem).

We use diesel and crude oil as fuel and the bypass valve doesn't have LVDTs.
I verified all the wiring and all seems good.
I even connected a new Moog directly to the TSVO but I got the same problem.

CSA:
I already changed the constant to 25% which resolved the problem for the moment but I am trying to understand the cause that making me crazy.
sometimes FAL>28% and sometimes <26%