[moved] Power generator on Boeing passenger planes?

[treez]

Hi, do you know what is the power bus on a Boeing passenger plane?....is it a 235VAC source as in the following link?

https://787updates.newairplane.com/787-Electrical-Systems/787-Electrical-System

Are there also batteries for eg the lighting etc , and what voltage are they?
Surely the 235VAC would simply charge up a battery bank? (via an ACDC charger)

 

[BradtheRad]

The article tells how the 787's designers gave ever more functions to be done by electricity, and it seems to include crucial systems. Perhaps lightning strikes are no longer the threat they used to be, because reports say an aircraft gets struck by lightning about once a year. So perhaps the designers installed safeguards against lightning.

The article also tells about redundant electric generators and redundant electrical wiring. Is it good to have the added weight? Having backups is good, and perhaps it's possible since there is less in the way of mechanical and hydraulics, and that lessens weight of the aircraft. But on the other hand isn't it sensible to have plain mechanical control over the aircraft, instead of electronic? Who can say for sure? I guess time will tell.

235 VAC... This brings land-based convenience up into the air. While inflight, both passengers and crew like to operate their appliances.

However there's an issue about bringing batteries on a commercial airliner, because of fires and explosions caused by Li-ion type. The FAA introduced rules saying what is and isn't permitted.
Their current webpage:

www.faa.gov/about/office_org/headqu...fo/media/Airline_passengers_and_batteries.pdf

 

[smijesh]

In aircraft, power generating through anteaters, output is 115V AC three phase at 400Hz to 800Hz. Then auto transformer rectifier unit will convert this power to 270VDC bus distributed over the aircraft. Most of the equipment will consume power from 270VDC bus. Some equipment required 28VDC, so converting from 270VDC to 28VDC as DC to DC converter. This is the overall view f aircraft power distribution system

Auxiliary power unit (APU) is an additional energy source normally used to start the engines. ram air turbine also is available as backup power in flight in the unlikely event of a power failure.

 

[treez]

Thanks, i presume its just a three phase rectifier that converts the three phase to DC?...and not three separate Boost PFCs (each having its own bridge rectifier) , one boost PFC on each on each phase?

 

[treez]

Whilst flying the other day, i wondered if there was much transient activity on the 115VAC bus?.....akin to mains transients as is well known to outdoor electrical fixtures.