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Emergency lights activation by DC bus 4 power loss

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Moderator
Registered: May 2009
Posts: 5140
Hi experts,

as we know, the emergency lights activate (using their inbuilt batteries) when DC bus 4 is unpowered.

I guess the power loss is sensed in the inbuilt battery chargers, because that's the only connection between DC bus 4 and the emergency light units.

DC bus 4 power goes to these units via P7 G14 (forward) and P7 G15 (aft).

So, am I right if I say the forward lights illuminate when I pull G14, and the aft lights when I pull G15?

In other words, the bus power loss is sensed after the CBs, not before them?


Cheers,

|-|ardy
Member
Registered: May 2010
Posts: 843
After the CB.

I just noticed that, according to photos and diagrams, all freighters have one CB only (G14 "EMER/LTS/CHARGING) and ER (pax) have 4 CB's (G12 & G13 "CHG EMER/LT [U/D MID"] and G14&G15 "EMER LTS/CHARGING [FWD AFT]".

Don't ask me why the titles are different on P7-1 and P7-2 :P
Moderator
Registered: May 2009
Posts: 5140
Thanks. Yes, I noticed that single CB on the freighter (and just 5 amps). I'll incorporate this difference in the next update, but I'll keep the normal pax config also for the ER-pax variant (slightly generalized).

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