Aircraft generator

[renzodelfabbro]

Do somebody known where I can find a scheme showing the connection between the aircraft-engine and the electric-AC-generator.
Thanks

 

[WKTaylor]

renzodelfabbro ..

Any A&P general textbook on the subject will have simple schematics. There are some texts with pretty sophisticated schematics [typical systems], also.

Some good websites for texts with aero-EE/EL topics...

http://www.aeroelectric.com/

http://12.111.162.100/

http://www.buildersbooks.com/

http://www.avionics.com/

Regards, Wil Taylor

 

[renzodelfabbro]

thank you wktaylor
but I'd like something more !
I just know turbojet aircraft for ex at take-off 12,000 RPM
6,000 RPM cruising, 3,000 RPM at landing, and so the alternator must be drive through a "constant speed drive" but I'd like to see the layout.
(BTW: sorry for my BAD english!

 

[rikman]

renzodelfabbro,

Perhaps the most common method of getting a constant speed output on modern turbine aircraft is to use an Integrated Drive Generator (IDG) mounted directly onto the engine's auxillary gearbox. This is a single unit that contains the basic generator (powered from the gearbox and therefore variable speed), a control unit (to adjust the power supply to the output drive to maintain a constant speed) and the constant speed output drive itself.

Hamilton Sunstrand hold most of the patents rights to this, though they do license other companies to produce their own versions. I'm not aware of any diagrams on the web, but the following link explains the basic principle:

http://www.fincor.net/pdf-files/eng.pdf

You could also try Hamilton Sunstrand's home page:

http://www.hamiltonsundstrandcorp.com/

- though I'm not sure if they give any details of how it works.

Rikman

 

[renzodelfabbro]

Thanks rikman

But I'd like a doc like this :

http://www.teijinseiki.co.jp/topics/20020802_presentation.pdf

( but in English .... of course

Ciao,
Renzo

 

[FredGarvin]

What exactly do you want to know. I work with CSDs and IDGs every day. If you are more specific I can help you.

 

[renzodelfabbro]

I know something about the single parts but I'd like to understand their layout ... so, for example, I'd like to know what "rikman" means when he writes... "(IDG) mounted directly onto the engine's auxillary gearbox" .
I'd like to see a real-scheme where there r the physical connection between the aircraft-engine and the Alternator
(... not the functional ones).
Thanks!
Renzo

 

[FredGarvin]

Well, I guess the easiest way to do that would be to show you an actual installation. Perhaps I can elaborate a bit on the previous explaination.

There is basically 2 different versions of the installation. The first is the older CSD/generator combination. The CSD is what is directly mounted to a pad on an engine's accessory drive. There will be a QAD ring or V-band clamp providing the actual restraint of the unit. The CSD will be coupled to the driveline via a splined shaft that is turned by the gearbox. The CSD will have an output shaft that extends out the end opposite that of the drive side. The end opposite the gearbox will have a female spline that will accept the male spline of the generator. The generator is mounted directly to the CSD and driven solely by the CSD, thus getting speed regulation. As far as electrical connections, there will be either 4 or 6 large gauge wires connecting the generator mains to the power bus. Three will be for each phase and the fourth (and possibly 5th and 6th) wire will be grounds or neutral leads. There will also be at least one plug that will connect the generator to the generator control unit (GCU) which will regulate the DC field voltage that regulates the output at the mains (and other things as well). If the generator is oil cooled, the CSD will share it's oil system with the generator by feeding thru the generator drive shaft to the rear bearing of the generator and nozzle for oil misting of the stator assembly. The combination is a large over hung assembly off of the gearbox.

The IDG is the newer version that combines both the CSD and generator into one assembly. It is conatained in one single housing. The theory and interface with the engine accessory drive is still the same however. The IDG can be either an in-line configuration or a side by side configuration. The side by side has efficiency advantages over the in-line version, but has a larger case size.

Hope this helps.