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Questions on 'Electrics'
07-11-2011, 12:07 PM
Post: #1
None of the above? :><.:
I don't see any answers there.

Real planes have propellers!
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07-11-2011, 09:47 PM
Post: #2
Let's do some elimination process.
When charging the lead acid battery, current is going INTO the battery, so we can remove answers b. and d.

The battery plates when discharged are covered with lead sulphate (which is actually lead + sulphuric acid), during charging they are converted back to Lead and Sulphuric acid is released back into the electrolyte (putting the acid back) Hence the best answer is a.

Also during charging current passing through the electrolyte and water will convert the water into it's elements, H2 and O which is released as gas into the atmosphere making the electrolyte more 'concentrated' ie 'loss of quantity/volume' that necessitates the usage of battery water/distilled water to be used to top up the level.
:^^:

Real planes have propellers!
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06-17-2012, 10:16 AM
Post: #3
Hi, I have a question for VSVF generator in A380.....How does the A380 regulate the frequency to constant 400 Hz when the generators cant give constant steady 400 Hz frequency to the instruments? and does B2 guys also needed when carry out hydraulic systems task in the hangar/line since A380 used EHV & EBHA as backup system for hydraulic?

“Learn from yesterday, live for today, hope for tomorrow. The important thing is not to stop questioning.”
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05-21-2014, 11:46 PM
Post: #4
nobody's thrown an answer to question asked by jack848.. i hope you will see my reply anytime soon.

VSVF gen.. variable speed, variable frequency gen,,.. if i still remember.

VSVF gen requires less mechanical rotating parts hence it lower the engine's effort in rotating it.. Unlike the constant speed generator which mechanically generates constant frequency but more effort from the engine is desired and of course more fuel needed.

BUt the question is : how the frequency is regulated if a system need a constant frequency? I would say SOLID STATE INVERTER is doing the job. To conclude, the main idea is to reduce fuel used by engines - then eliminate heavy mechanical parts -then replace with solid state device.

for second question it depends on the QA system in a company.I'd rather say for b1 the function is limited to normal operational check + removal/installation + visual inspection. Normally for a system which requires special functional check for electrical/electronic+ the used of 'test set' then the B1 and b2 will overlap meaning that they both certify.

“A friend cannot be considered a friend until he is tested in three occasions: in time of need, behind your back, and after your death.”
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05-22-2014, 05:38 PM
Post: #5
Good answer mosumo.
It's a type rated question, hence I did not response. (A380)
However smaller jets that i came across, namely Challengers and the like, also uses 'frequency wild' generator.
No issues if the electricity is used for lighting and power but frequency sensitive equipments will be fed from a box that generates constant voltage and frequency.

Real planes have propellers!
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05-25-2014, 07:02 PM
Post: #6
from the question, i would say (guess) jack848 is now doing his study in getting his LWTR Smile

btw the trend now moving a lot to electronic system due to it's wide range of application and lots of weight reduction but as usual there are pros and cons. like modern cars nowadays...sensors / box problematic issue is a nightmare to me.

I heard a story (this is confirmed) an aircraft (one of our operator) went crazy about it's altitude control during almost entire flight except for take off and landing although it is not caused by weather. it was approx a 1 hour flight time. The whole cabin went silent and only prays accompanied. No in-flight serviced allowed and after landing the whole pax and crews felt so lucky and grateful.

“A friend cannot be considered a friend until he is tested in three occasions: in time of need, behind your back, and after your death.”
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