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-   -   RAT to electrical current ??? (https://www.pprune.org/tech-log/381048-rat-electrical-current.html)

a400 12th Jul 2009 09:35

RAT to electrical current ???
 
If anyone has any technical publication or knowledge how rotation of RAT produce Hydraulic pressure on Blue system (A320) and than respectively Electrical current to aircraft systems.:confused:

I appreciate any feed back.

Thanks:)

Jimmy Do Little 12th Jul 2009 10:56

If I understand your question correctly...

The RAT is a "Wind Powered Hydraulic Pump", much like a Wind-Turbine, but in this case attached to the belly of the aircraft.

That pump, powers the Blue Hydraulic System, just like the electric motor normally would. Most hydaulic pumps require some sort of motor - electric, engine driven (accessory case), etc - to power a Hydraulic pump . In this case, it's basically the free spining propellor of the RAT that powers the pump.

Next, an Electrical generator is powered by the Blue Hydaulic system.

Was this what you were looking for? Let me know if you would like me to email you that section of the FCOM or AMM.

Cheers

Akrapovic 12th Jul 2009 11:00

Electrical generator - Wikipedia, the free encyclopedia

a400 12th Jul 2009 11:10

Jimmy

Yep as you explained first part up to Hydraulic Pressure I have no problem with.

But I am still wondering how is Electrical Generator powered by Blue Hyd, System, this is gray area to me. How Hydro pressure turn electrical generator that is question.

Thanks for books I have them but could not find answer.

jimpy1979uk 12th Jul 2009 14:10

The RAT allows the blue system to be pressurised which in turn runs the CSMG (constant speed motor generator) its a hydraulic motor with a generator on its output.

It is controlled by its own GCU which maintains the speed of the motor by varying a swash plate within it. Which in turn maintains the output of the generator at 115Vac, 400Hz.

Depending on what it delievering pressure to the blue system also determines the output available in kVA of the CSMG. When its the RAT the output is its lowest.

Jimpy

Jimmy Do Little 12th Jul 2009 14:55

I assume that you understand how the PTU works. Just imagine that you connect a generator to the output side of the PTU, and basically you have the system.

a400 12th Jul 2009 17:15

OK

bit of google bit of PPRuNe and AMM and picture is clear :8

Thanks for help :ok:


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