ESS PWR SEL

[execeng]

Would like to clear up 3 (4) questions:
1) The ESS PWR SEL only selects the source of electrical power for
the ESS AC Bus. Correct?
2) If the selected source fails, does the STANDBY BUS automatically
receive power from the battery via the static inverter? (until the
ESS SEL is switched?)
3) In the event of an engine failure, or generator failure, do the
packs and galleys automatically get kicked of the line?
Thanks, louross.

[Boeing Fixer]

> 1) The ESS PWR SEL only selects the source of electrical
>power for the ESS AC Bus. Correct?

It does select the source for only the ESS AC bus as well as selecting the STANDBY in the event of complete AC power loss.


> 2) If the selected source fails, does the STANDBY BUS
>automatically receive power from the battery via the static inverter?
>(until the ESS SEL is switched?)

Short answer is no. There is no AUTO switching for STANDBY BUS power. The ESS POWER selector must be moved to an operating AC source to restore ESS AC power. It's the job of the F/E S/O to ensure the ESS buses are always powered.


> 3) In the event of an engine failure, or generator failure,
>do the packs and galleys automatically get kicked of the line?
>Thanks,

There is no auto power sheding on the 727. It's the back seaters job to do this function. The late model 727's had an AUTO PACK TRIP feature for an engine failure on takeoff as well as a reserve engine power feature.

[execeng]

Okay, thanks for clearing that up for me, louross.