Spinning disabled in Siemens SGT400 gas turbine


Thread Starter


Dear all,

We are having 3 nos of Siemens SGT400 type gas turbine to fulfill of our plant power requirements.

In that, one GT we are having a unsolved issue that is, While giving Start Command/Timed spin or whatever we are getting a alarm as "Starter motor failed to turn GG Shaft" after that starter motor gets stop command...

This is happened once we were given a normal stop command to that machine when it was running smoothly while the machine was in coasting down we got a first alarm as "Automatic spin at shutdown <b>disabled</b>" thereafter only we got a alarm "Starter motor failed to turn GG Shaft"

We are suspecting that the logic for automatic shutdown is disabled somehow and the same to be we wants to enable.

I'm looking forward from you all a meaningful solution for this issue...

(GG Shaft- Gas Generator Shaft)

Thanks & regards,

Bintulu Mari

Dear John,

I can't help you here.

Anyhow, probably you want to ask these questions to your Siemens CSA/LTSA FSR/Resident Engineer :-

1. I assumed your plant is on Island mode.

2. Do you have interlock function(s) permissive between these 3 GTs? To allow next GTG to be started-up? Maybe 1 or more interlock function(s) prevent you to pursue the 3rd GTG starting up...

3. What is the objective/purpose of this Alarm: "Starter motor failed to turn" ...my speculation; this Alarm is telling you that prevent starting-up sequence due to hot rotor/ rotor bow after immediate coasting down...hence the logic will prevent you to prevent starting-up sequence...

4. What is the objective/purpose of this Alarm: "Automatic spin at shutdown disabled"...my speculation; this Alarm is being activated that Automatic Spin at shutdown sequence being prevented by permissive/pre-requisite logic whereby to protect the rotor blades, fuel gas valves train problem(s), temperature conditions, or flame
sensor(s) or flame scanner being not healthy or etc...

All the best to you John.

If you don't mind, share your fault findings and what was the culprit.