AC / DC System B737
 

hello

I am reading a little about the B737NG, and when talking about the electical system they always mention AC and DC. I know this means Alternating Current and Direct current, but what I don't understand is if they come from different sources, or how that works??

If someone could explain this to me I would be most happy! Or if someone has a good link to a good explanation!

thanks, pt

AC to DC is via Transformer Recitifiers. They are listed as TR 1 TR2 and TR 3 on this schematic...



Hope this helps...B737 Electrical Schematic

Be awarre that the electrical systems on the Classic and Next Gen are pretty different.

The the basics are always the same.

The primary sources of AC power are the (2) IDGs (Integrated Drive Generators) which are engine-driven and the APU Starter-Generator. There is also External Power.
In an emergency, Standby AC power can be supplied by a Static Inverter which changes DC to AC power.

The primary sources of DC power are the (3) Transfornmer Rectifers which rectify 115VAC (from the generators or External power) into 28VDC. The battery also supplies 28VDC.

737 APU starter/geny?!

They must have changed a lot since I last worked them.:suspect:

:confused:

Yes the APU has a starter/generator capable of 90KVA up to 31K and 66KVA up to 41K. Things they are a changin'
Don't forget the battery charger is on line when it's charging and the battery when the charger is cutoff. That makes four sources of DC on the NG with the engines running.

http://www.b737.org.uk/electrics.htm
Here's the rest of the story after you look at the schematics.