Dash 8 dc gen fail
04-08-2011, 07:33 AM
#1
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Dash 8 dc gen fail
Hi,
working on my take home aqp. If a dc gen fails, I know the main busses will tie thanks to the bus tie logic system. What I want to make sure I'm clear on is, the secondary busses will not tie so long as the mains tie. If for some reason the mains fail to tie, perhaps due to both dc gens failing, that is when the secondaries will tie, providing current via the trus to each main?
Thanks
working on my take home aqp. If a dc gen fails, I know the main busses will tie thanks to the bus tie logic system. What I want to make sure I'm clear on is, the secondary busses will not tie so long as the mains tie. If for some reason the mains fail to tie, perhaps due to both dc gens failing, that is when the secondaries will tie, providing current via the trus to each main?
Thanks
04-08-2011, 10:56 AM
#3
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Joined APC: Jul 2010
Position: duck & cover
Posts: 142
'DC Logic' will try to tie horizontal (main to main) first and if not avail.. in your senerio then go vertical.. secondary to main. Think of it this way..
DC logic will try to find a like source first: main 2 main, secondary 2 secondary.
I think that was your question...
DC logic will try to find a like source first: main 2 main, secondary 2 secondary.
I think that was your question...
04-08-2011, 01:31 PM
#4
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100 and 300. That's it. Just wanted to make sure. So long as the mains tie, there is no need in that example for the circuit to close from the secondary to a main.
Also, with main bus tie switch to ON, how does that affect auxillary battery power on the left bus vs main battery power when only on battery power. ie, does the auxillary battery power only the left main and essential bus, or will the main battery power both mains, leaving the auxillary to only the left essential bus?
I hope this question makes sense.
Thanks again!
Also, with main bus tie switch to ON, how does that affect auxillary battery power on the left bus vs main battery power when only on battery power. ie, does the auxillary battery power only the left main and essential bus, or will the main battery power both mains, leaving the auxillary to only the left essential bus?
I hope this question makes sense.
Thanks again!
Last edited by CentralPa717; 04-08-2011 at 01:33 PM. Reason: forgot a word
04-08-2011, 03:40 PM
#5
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Joined APC: Mar 2008
Position: B777/B787 - Flight Test
Posts: 317
Originally Posted by CentralPa717
Also, with main bus tie switch to ON, how does that affect auxillary battery power on the left bus vs main battery power when only on battery power. ie, does the auxillary battery power only the left main and essential bus, or will the main battery power both mains, leaving the auxillary to only the left essential bus?
Any more questions, feel free to PM me. You'll need to make 10 posts on APC first.
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