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Old 26th Apr 2016, 15:21
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NSEU
 
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I am not talking about the Battery, I am talking about the BAT BUS and its indications on the AC/DC metering panel
Sorry, I made this mistake, too. I was confusing BAT with BAT BUS (so the Maintenance Manual is not as ambiguous as I originally thought).

It appears that there is no amperage shown (ever) with the switch in BAT BUS or STBY POWER because it is like this by design. There will be current flow of course with the right circumstances, but, for example, in the case of the BAT BUS, current measurement may not be so easy:
The BAT BUS is broken into 3 sections. Looking at the wiring schematics, the BAT BUS voltage reading appears to be looking at BAT BUS Section 2 only. Voltage will be common to all 3 (parallel) sections (assuming all 3 contacts of the relays are functioning), but the current will be different in each BAT BUS section depending on the load in each branch.

It would probably all make sense to you if you could see the wiring schematics but, sorry, I can't post diagrams here (for copyright and other reasons). The K1 and K2 relays (on Wiring Schematic 24-61-11) are wired up in such a way that it wouldn't be possible to put an ammeter in the circuit at a single point to get a reading of the current in all three BAT BUS Sections in all normal/abnormal situations. Under normal situations, TRU 3 feeds all three BAT BUS sections (and you have the amperage data in the "TRU 3" meter position anyway). When the BAT BUS is powering the DC Busses under abnormal situations, the "BAT" meter position will offer general current information (but note that the BAT may be powering lots of other busses too under certain circumstances: e.g. Standby DC, Hot Bat, Hot switched BAT).

Anyway, I hope this helps more than it hurts

Cheers
NSEU
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