737NG EGT Start Limit Line.

[B737NG_Pilot]

Hello Everyone,

While doing the before taxi procedure, we cannot connect, the Generators to the respective transfer buses, while the EGT Start Limit Line is displayed. How this achieved?

[de facto]

Im not sure ..oh yes I am now...:E

[de facto]

Ok now i feel bad,maybe its a genuine question.
The EEC is sending the EGT info to the your display via the DEU.
As long as the EEC is powered you will get power for your EGT indication.
Now in your example,your power source for the EEC is from the APU powering your transfer buses.
EEC gets power from transfer bus until about 15% N2 then by its own generator.

[B737NG_Pilot]

Defacto, thanks for your reply.

But my question is related to the GEN OFF bus light. We cannot connect the GEN 1 or GEN 2 to the respective engine, unless the EGT Start limit line has disappeared. How is this achieved? I want to know about the mechanism which prevents this.

[de facto]

My bad ,read your question too quickly..:rolleyes:
The GCU is monitoring that the IDG voltage/frequency is good among other things before the gens can be put on bus..
One is that the voltage must be stable for at least 20 secs...
Since your EGT redline still showed it means you tried to put the load on before your engine was at idle.
If it wasnt stable at idle (egt red line on) it couldnt have had 20 sec of stable output so you couldnt connect them.

Now my question is why would you try to put the gens on bus before the engine reached idle in the first place?

[B737NG_Pilot]

Well that's make it clear. Well I did try connecting the generator a couple of time, before the EGT Start Limit disappeared. Hence the question. Just trying understand the system better. A lot of things are not very clear in FCOM.

[Skyjob]

Please armed with the knowledge presented, could you explain as asked:
why would you try to put the gens on bus before the engine reached idle

[de facto]

B737NG_Pilot

Join Date: Mar 2013
Location: Mumbai
Posts: 65
Well that's make it clear. Well I did try connecting the generator a couple of time, before the EGT Start Limit disappeared. Hence the question. Just trying understand the system better. A lot of things are not very clear in FCOM.


So make it clear...you have got a copy of an FCOM and you are a PC sim player right?

[latetonite]

Seen all the posts of B737-NG, he must be trying to get B737-typed on a Flite Simulator X on his home computer.