In our site 9e Ge gas turbine i noted that crank motor didn't stop after 1800 rpm and FSNL, and it rotate with low speed. the site supervisor sad this normal condition? is this true? and what can we do to over come this problem? and what is the drawback of this problem?

other problem that gas purge vent didn't close at its time (we work with liquid fuel), and it need to toggle forced. what is the drawback of leaving it open for one or to hour until i&c engineer came and force it to close?

 

ibr2016,

How fast is the cranking motor spinning? Rated Speed?

What is the state of L52CR when the unit is at FSNL?

Which purge vent solenoid are you talking about? 20VG-1?

If it's 20VG-1, why would you think 20VG-1 should be closed when the unit is starting or operating on liquid fuel?

 

ibr2016,

Without more information, we can't comment on the gas fuel purge/vent valve.

As for the cranking motor, I suspect it's not really running--meaning that it's not getting voltage/current at it's terminal from the mains high voltage supply. More likely there is some condition in the torque converter that is causing torque from the output shaft of the torque converter to work "backwards" through the torque converter, causing the starting motor shaft to turn.

The reason could be a failed or failing 20TU-1, or some other similar problem. If the unit has 20TU-2, it could be a failed or failing 20TU-2.

But, again, we don't have enough information to be of much more help.