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HAWK21M
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Ground Cables Near Bay

Wed Jun 28, 2006 2:07 am


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Explain the Yellow Container & the Yellow Cables.Something to do with Ground Power.Why Two cables.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
kaddyuk
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RE: Ground Cables Near Bay

Wed Jun 28, 2006 2:12 am

The A330 has two busses to supply power to the aircraft, PWR A can supply the whole ship with PWR B also reducing the load.

You can run the aircraft from just A or just B however A is prefered, B will be automatically used if available.

I think some systems will not function with just PWR A connected however dont quote me. I've not sat the A340 Gen or Tech Fam course yet, only the B744...
Whoever said "laughter is the best medicine" never had Gonorrhea
 
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HAWK21M
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RE: Ground Cables Near Bay

Wed Jun 28, 2006 2:34 am

What Wattage. 90KVA
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
Tristarsteve
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RE: Ground Cables Near Bay

Wed Jun 28, 2006 2:54 am

Sorry don'y know A330, but on B777 and B744 there are two ground power connectors.
The B777 will operate on one, but it must be Nbr 1 or the ground handling bus is unpowered. However with 90kva you are up at 80pc all the time. If you want to turn on pumps or ovens then a second 90kva connector is required.
We always connect two ground power on B777 at ARN, but I see SAS only has one on their A330.
The electrical system will protect the aircraft from overload if only one is fitted by a load shedding system.
 
kaddyuk
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RE: Ground Cables Near Bay

Wed Jun 28, 2006 3:18 am

Quoting TristarSteve (Reply 3):
The B777 will operate on one, but it must be Nbr 1 or the ground handling bus is unpowered.

Thats the one... I was trying to remember, its a similar method with the Airbus. If you wish to operate hyds, flaps or other functions, you'll need PWR B as well as PWR A.

I normally split the ship if the APU is available (Normally for Air Con). Have the APU Supply the AC Power and have PWR A as back up. That way, if either fails, you wont loose power.
Whoever said "laughter is the best medicine" never had Gonorrhea
 
n8076u
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RE: Ground Cables Near Bay

Wed Jun 28, 2006 3:27 am

I can't speak of the A330, but in general, if there are two receptacles on the aircraft, you need to use both if you need to run all/some of the galley ovens. Otherwise, one is usually sufficient, but there may be exceptions. On the 744, the aircraft will load shed with only one source plugged in if you try to run a lot of users. We used to do "B" checks with only one plug, and that was sufficient for our purposes, and never used more than one at the gates as well. If I remember right, you use the rear plug first on the 744.

90kva sounds right to me, but it's been a few years.

Chris
Don't blame me, I don't work here...
 
kaddyuk
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RE: Ground Cables Near Bay

Wed Jun 28, 2006 3:29 am

Quoting N8076U (Reply 5):
90kva sounds right to me

I've got 115KvA stuck in my head, i'll check tomorrow morning at work...  Smile
Whoever said "laughter is the best medicine" never had Gonorrhea
 
Tristarsteve
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RE: Ground Cables Near Bay

Wed Jun 28, 2006 3:31 am

Quoting N8076U (Reply 5):
you use the rear plug first on the 744.

Correct. Why did Mr Boeing make it the rear plug on B744 and the fwd plug on B777? Our rampers can never remember, but if they get it wrong and I shut down the APU then they have no power in the holds!!
 
n8076u
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RE: Ground Cables Near Bay

Wed Jun 28, 2006 4:58 am

Quoting Kaddyuk (Reply 6):
I've got 115KvA stuck in my head, i'll check tomorrow morning at work...

That could very well be. Keep in mind we had a lot of old ground equipment as well, and the newer terminal areas may have had higher output at the built-in power connections than at our vintage 50's-60's era maintanance base.  Wink

We had some tugs that had GPU's built into them, and were apparently handy, so I've been told, for towing aircraft with a dead APU or something like the DC-8 that had no APU. But that was a bit before my time, and they were never used while I was there.

Quoting Tristarsteve (Reply 7):
Why did Mr Boeing make it the rear plug on B744 and the fwd plug on B777? Our rampers can never remember, but if they get it wrong and I shut down the APU then they have no power in the holds!!

It does seem inconsistent, doesn't it!

Chris
Don't blame me, I don't work here...
 
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HAWK21M
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RE: Ground Cables Near Bay

Wed Jun 28, 2006 11:56 am

Quoting N8076U (Reply 5):
If I remember right, you use the rear plug first on the 744.



Quoting Tristarsteve (Reply 7):
Correct. Why did Mr Boeing make it the rear plug on B744 and the fwd plug on B777

Any Pic of the Panel Connectors.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
dl757md
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RE: Ground Cables Near Bay

Wed Jun 28, 2006 12:14 pm

Quoting TristarSteve (Reply 3):
but on B777 and B744 there are two ground power connectors.

764 as well.

DL757Md
757 Most beautiful airliner in the sky!
 
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HAWK21M
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RE: Ground Cables Near Bay

Wed Jun 28, 2006 4:56 pm

Quoting Dl757md (Reply 10):
764 as well.

Hows it on the Earlier Versions ie B762/3.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
n8076u
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RE: Ground Cables Near Bay

Wed Jun 28, 2006 5:38 pm

Quoting HAWK21M (Reply 11):
Hows it on the Earlier Versions ie B762/3.

Just one if I am not mistaken. It's been a couple years...

Chris
Don't blame me, I don't work here...
 
Tristarsteve
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RE: Ground Cables Near Bay

Wed Jun 28, 2006 10:07 pm

Quoting HAWK21M (Reply 11):
Hows it on the Earlier Versions ie B762/3.

Yes only one, same location as B757
 
pygmalion
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RE: Ground Cables Near Bay

Thu Jun 29, 2006 12:57 am

The 787 will have 4 90 KVA connections. 1 pair in front and one in back.

See Boeing site on airport planning for details...

http://www.boeing.com/commercial/airports/acaps/787sec5.pdf
 
2H4
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RE: Ground Cables Near Bay

Thu Jun 29, 2006 1:13 am



Welcome to Tech/Ops, Pygmalion!




2H4


Intentionally Left Blank
 
pygmalion
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RE: Ground Cables Near Bay

Thu Jun 29, 2006 1:16 am

Quoting 2H4 (Reply 15):

Thanks, I've been lurking for a while and finally decided to express myself by spending $25.
 
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HAWK21M
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RE: Ground Cables Near Bay

Thu Jun 29, 2006 1:43 am

Quoting Pygmalion (Reply 14):
The 787 will have 4 90 KVA connections. 1 pair in front and one in back.

Wow.I guess that'll be the Max till date.
BTW Welcome.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
Tristarsteve
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RE: Ground Cables Near Bay

Thu Jun 29, 2006 1:54 am

Quoting Pygmalion (Reply 14):
The 787 will have 4 90 KVA connections. 1 pair in front and one in back

I wonder how many airports can supply 4 good GPUs!
We have one FEP 90kva on each stand, and for B777 we need one GPU as well. Our handling agent has six GPUs, but only one of them will supply the exact freq and volts that the B777 needs. We find that GPUs that work perfectly on B737 will not work on B777 because the newer aircraft has much tighter volts and freq requirements.
I wonder how many units the B787 requires for engine start? I hope that 2x 90kva is enough otherwise it will be difficult to posn two GPU behind the wing during engine start.
Perhaps everyone is buying new GPU!!
 
pygmalion
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RE: Ground Cables Near Bay

Thu Jun 29, 2006 2:05 am

My understanding is that a minimum of one is "required" but much load shedding will occur during engine start. 4 only required for full ground test of all systems without engines running. Normal use is both of the forward connections. If APU is not available, then engine start is done electrically from ground power. There is no bleed air start for 787, only electric.
 
pygmalion
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RE: Ground Cables Near Bay

Thu Jun 29, 2006 2:11 am

Oops, you need minimum of two to start without APU. I should read the links I post.  Yeah sure
 
Tristarsteve
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RE: Ground Cables Near Bay

Thu Jun 29, 2006 2:15 am

Quoting Pygmalion (Reply 20):
Oops, you need minimum of two to start without APU

That makes more sense, thanks.
Also I hear that the B787 will have frequency wild generators. Does this mean that the GPU frequency will not be so important?
 
n8076u
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RE: Ground Cables Near Bay

Thu Jun 29, 2006 4:11 am

Quoting Pygmalion (Reply 19):
engine start is done electrically from ground power

Although my first reaction is to say "bless them for that", I am wondering if that will open up a whole new can of worms, being ALL electric?

Quoting TristarSteve (Reply 21):
Also I hear that the B787 will have frequency wild generators.

Does that mean direct drive, no CSD? Would there be some sort of frequency converter to change the random freqs to 400hz? Seems like the CSD is the easier way to go. Pardon my question if I misunderstood "frequency wild"!

Chris
Don't blame me, I don't work here...
 
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HAWK21M
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RE: Ground Cables Near Bay

Thu Jun 29, 2006 5:02 pm

Quoting TristarSteve (Reply 21):
Also I hear that the B787 will have frequency wild generators.

Whats this term supposed to mean.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
Tristarsteve
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RE: Ground Cables Near Bay

Fri Jun 30, 2006 4:38 am

Quoting N8076U (Reply 22):
Does that mean direct drive, no CSD? Would there be some sort of frequency converter to change the random freqs to 400hz?

Yes it means that there is no CSD. The generators are bolted on the gearbox and the frequency is dependent on engine speed.
The B777 BUG (Back up generator) is frequency wild. There is a convertor in the Electrics bay to convert it to 400Hz.
When the B737-400 was introduced it had frequency wild generators on the CFM56. The converor was bolted onto the generator. It was not very successfull and we replaced ours with conventional IDGs after a couple of years.
 
n8076u
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RE: Ground Cables Near Bay

Fri Jun 30, 2006 5:09 am

Quoting TristarSteve (Reply 24):
It was not very successfull and we replaced ours with conventional IDGs after a couple of years.

Hence my question.  Wink

Quoting TristarSteve (Reply 24):
The B777 BUG (Back up generator) is frequency wild.

Yes, it is, I forgot all about that! But then again, it is also a backup source, so I could see the benefit of not carrying what I can only imagine would be a heavier csd portion around all the time, but instead a lighter electronic frequency converter unit, which would only ever be used "in a pinch".

But I suppose technology has advanced to the point that the electronics could be more reliable and trouble-free than the CSD portion of the IDG would be, where a couple years ago, that would not have been the case.

Thanks much for your insight, TristarSteve.

Chris
Don't blame me, I don't work here...
 
FlyDeltaJets
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RE: Ground Cables Near Bay

Mon Jul 03, 2006 9:12 pm

Quoting Pygmalion (Reply 20):
Oops, you need minimum of two to start without APU. I should read the links I post.

Techncally if the air start is hooked up and is on airpacks mode you dont need any as the cart is acting as an APU thats on a 763 i know for sure.
The only valid opinions are those based in facts
 
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HAWK21M
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RE: Ground Cables Near Bay

Mon Jul 03, 2006 10:12 pm

Quoting FlyDeltaJets (Reply 26):
you dont need any as the cart is acting as an APU thats on a 763 i know for sure.

Is the B763 APU common with type with the Earlier B767 models.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
Tristarsteve
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RE: Ground Cables Near Bay

Mon Jul 03, 2006 10:20 pm

Quoting HAWK21M (Reply 27):
Is the B763 APU common with type with the Earlier B767 models

B762 763 and 757 APU are all the same (on our airline anyway).
 
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HAWK21M
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RE: Ground Cables Near Bay

Tue Jul 04, 2006 5:41 pm

Quoting Tristarsteve (Reply 28):
B762 763 and 757 APU are all the same (on our airline anyway).

Apart from the GTCP 331-200ER.Is there another option.
regds
MEL
I may not win often, but I damn well never lose!!! ;)

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