A320 blue system

[dartagnan]

I am revising the systems on the 320,just a question to the A320 pilots to resume if i got it right, I seem to be confused now!!!.

the electric pump on the blue system is powered after starting both engines.
the 2 engines power the battery which powers the electric pump, ...right?

in case of 1 and 2 engine shutdown (case of contaminated fuel)or AC1 &2 lost, the RAT exits automatically.
the RAT powers the hydraulic pressure at least 2500psi, and in same time charge the batteries(the RAT has 2 function, to pressurize the blue system and load the battery).The battery make turn the electric pump which pressure the blue pressure too(???).so in this case we have the blue electrical pump and the RAT which pressurize the blue system?



when the RAT stalls below 120 knots, I have enough power for 30 minutes to power the plane in emergency mode(NAV1, VHF1, ...).in this case the battery powers the bluepump, and after 30 minutes(when batteries are dead) I loose all hydraulic pressure(so I have to be sure to be on the ground).

please, ad you comment, and correct me. thank you.

[celtic mech]

I am gonna answer this in relation to the A330, which runs along the same kind of idea, except the Emer Gen is via the Green System instead of the Blue System. Slight Differences but nothin too major.
The Rat can Extend on 2 circumstances. There are 2 Solenoids on the RAT...one for Manual Extension via RAT MAN ON p/b overhead in cockpit Or 2nd solenoid via Automatic deployment Logic.
Ok, RAT drops for either of the above reasons...Airspeed causes RAT to turn, thus turning causing the Hydraulic Pump located on the back of the RAT to pressurize the Green System exclusively. The Green system then allows the CSM/G (EMER GEN) to run....i.e We now have Electrics provided. (limited as they are). Certain Shedding occurs obviously as the output of the EMER GEN is not the same capacity as the EDP's.
Coming in to Land, you are using the EMER GEN...under a certain airspeed the RAT will not be able to produce enough HYD Pressure to maintain the systems...this is when you can press the LAND Recovery P/B and this will then draw the power required via the Batteries.

You said in your post above " the 2 engines power the battery which powers the electric pump, ...right?"... The Engines are running...The Electrics that we have on the aircraft come from the Engine via the IDG's....basically,they convert the turning motion into electrical power...and this what the aircraft is powered from...under normal circumstances Engine 1 powers AC Bus 1 and Engine 2 powers AC bus 2. The batteries are fed from the DC Bat Bus. which under normal circumstances comes from DC BUS 1 via the TR from AC Bus 1. The Batteries are controlled by the BCL's...Battery Charge Limiters...these "connect" the batteries to the DC Bat bus whenever the voltage of the battery in question goes below a certain value...therfore the system now re-charges the batteries and when fully charged, disconnects them. The Elec Hydraulic pumps are not powered via the batteries. they are fed from the AC Bus.

Hope this helps!

[OutOfRunWay]

The Blue Pump is available when

1)there is AC power (not just Battery) with or without engines running in flight, and


2) AC power avail and one engine running on the ground.

3) There is also a Blue Pump Override switch which will force it to on regarless

The RAT extends on loss of both AC Busses and will pressurize the Blue system to 2500 psi(I think, cant look it up now)

The RAT does not have its own Generator and hence does not Provide AC power directly. AC Power is provided by an Emergency Generator running off the Blue Hyd system.

If your RAT stalls (at 100 kt, I seem to recall), the Batteries will power the AC busses via the static inverters. The AC SHED DSS and DC SHED DSS busses are .. well.. shed.

I really dont know how long your bats will last in this configuration..

Cheers, and good luck to you.
OORW

[Clandestino]

RAT on A320 deploys automatically if both AC buses are lost - if both engines fail, this is certanly gonna happen.

Blue hyd pump is powered by AC1 bus only, it can never be powered by battery.

If you lose both donkeys and you're left with blue hyd (pressurized by RAT) only, the RAT stall at 100kt will be pretty much irrelevant to you, as flaps will be lost and slats will be available up to config 3 or 22° (they can be set to full, or 27°, but it's not recommended with no flaps) and even empty A320 would stall above 100kt in that config.

[dartagnan]

AC Power is provided by an Emergency Generator running off the Blue Hyd system.this is where I am confused I guess. the Emergency generator is NOT the RAT.(I thought the RAT was providing pressure and elec)...

So how this Emergency generator turns to provide AC?(mechanically spoken).

I have never Seen a RAT deployed, except some pictures on line.the RAT if I am correct just pressurize the system, nothing else?

in this case it is just a rotating pump with the same fluid in the blue system, or it is like the Power transfer unit (PTU)with no tranfer of fluid, and in this case the RAT has his own fluid?

[allthatglitters]

the electric pump on the blue system is powered after starting both engines.Wrong

The blue pump runs automatically when either engine is started and ac power is avail.
With ac power avail, the blue pump runs automatically if the nose landing gear shock strut is extended. (Sensors GA24 or GA25).

Auto RAT extension requires airspeed and posssibly to be in the air. As when doing the auto Rat deployment test we have to switch the ADIRU #1 On and simulate an airspeed and in air mode.

[Polarhero]

To put it simply the rat turns a pump that pressurises the blue system, this in then turn a hydraulic motor to turn the emergency generator to provide power.

There is no direct drive to the generator from the rat, only hydraulic power.

Cheers

:ok:

[79wwow]

The green hydraulic circuit drives an emergency generator that automatically supplies emergency AC power to the aircraft electrical system, if all main generators fail. This generator supplies 8 KVA of three-phase 115/200 V 400 Hz power, except when the Ram Air Turbine powers the green hydrauliccircuit, and the aircraft speed is below 260 kt; in this case, the emergency generator supplies 3.5 KVA, leading to some shedding.

[noptawat]

I am revising the systems on the 320,just a question to the A320 pilots to resume if i got it right, I seem to be confused now!!!.

the electric pump on the blue system is powered after starting both engines.
the 2 engines power the battery which powers the electric pump, ...right?

in case of 1 and 2 engine shutdown (case of contaminated fuel)or AC1 &2 lost, the RAT exits automatically.
the RAT powers the hydraulic pressure at least 2500psi, and in same time charge the batteries(the RAT has 2 function, to pressurize the blue system and load the battery).The battery make turn the electric pump which pressure the blue pressure too(???).so in this case we have the blue electrical pump and the RAT which pressurize the blue system?



when the RAT stalls below 120 knots, I have enough power for 30 minutes to power the plane in emergency mode(NAV1, VHF1, ...).in this case the battery powers the bluepump, and after 30 minutes(when batteries are dead) I loose all hydraulic pressure(so I have to be sure to be on the ground).

please, ad you comment, and correct me. thank you.




the electric pump on the blue system is powered after THE FIRST ENGINE START!

the RAT exits automatically when AC1 and AC2 bus are loss to energize an emergency generator !
RAT -> HYD power to BLUE -> HDY Emergen -> AC EMER


when the RAT stalls below 120 knots, I have enough power for 30 minutes to power the plane in emergency mode(NAV1, VHF1, ...).in this case the battery powers the bluepump, and after 30 minutes(when batteries are dead) I loose all hydraulic pressure(so I have to be sure to be on the ground).

NEGATIVE! Batt never power the BLUE. since 140 is fair for approach speed (see QRH). You will not fly A320 at speed 120 for 30 mins in ELEC-EMER !

Please see QRH or FCTM ELEC-EMER section will give your more what is going on here !

SIR

[sonicbum]

please, ad you comment, and correct me. thank you.

FCOM DSC-29 a couple of times from TOP to BOTTOM then come again for the questions. Does not really seem You have done that so far.

[IFixPlanes]

FCOM DSC-29 a couple of times from TOP to BOTTOM then come again for the questions. Does not really seem You have done that so far.

A little bit harsh, but you are absolut right:D

[akindofmagic]

FCOM DSC-29 a couple of times from TOP to BOTTOM then come again for the questions. Does not really seem You have done that so far.

Maybe he has done so in the ELEVEN SODDING YEARS since this question was posted. :ugh:

[sonicbum]

Maybe he has done so in the ELEVEN SODDING YEARS since this question was posted. :ugh:

Maybe... :)