Landing Lights

ericmark · 26 Feb 2009

I saw a post on Landing lights and it got be thinking again to when I worked with Aircraft Ground Lights (AGL) there all had transformers going to lights and the primary of the transformers were wired is series.
I was never able to understand why? Seemed a very odd way to wire transformers any ideas why?

Taylortwocities · 27 Feb 2009

Perhaps its an easy fault location method: one out, all out sort of thing..

ericmark · 27 Feb 2009

May be I was only on them one day, had to be in pairs for safety and his normal partner was off sick so I had to fill in for day. Just did as I was told. But I have often wondered why since. And Falklands is a bit of long track to ask.

Taylortwocities · 27 Feb 2009

In that case...
I'll bet the landing light systems were Yank. The primaries would be 110V and the base supply is UK 230V so they just wired the transformers in series pairs.

holmslaw · 27 Feb 2009

Taylortwocities · 27 Feb 2009

Not like the jungle airstrips that you work on now,
With those "special consignments"??

holmslaw · 27 Feb 2009

Taylortwocities · 27 Feb 2009

Untitled

Taylortwocities
17 Apr 2008
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ericmark · 28 Feb 2009

holmslaw said:
I worked on airport lighting years ago, not absolutely sure about the voltages.

Each light has its own 5kv to 12volt transformer called a pot - they're about the size of a 5" flowerpot. From each pot a standard flex is taken to each light.

They are wired in series via a single core cable armoured with copper tape and a 6mm core.

A typical runway would have 2 or 4 overlapped circuits and the cables will run for miles and miles.

Because in a series circuit the current is the same in all parts, they are fed via current controllers. During commissioning, the voltage is adjusted on each circuit to get 100% brilliance and the current is measured. And the controller is set to that maximum current. So if you want full brilliance you allow full current to flow, 50% current you get 50% brilliance.

Yes that seems to line up with what I know of the system I know they were very expensive and that would explain why. And yes with length of runway some method would be needed to stop the effects of volt drop so all seems to fall into place. Thank you very much wish I had asked more about it at the time. Eric

ban-all-sheds · 1 Mar 2009

holmslaw said:
Stuff

http://en.wikipedia.org/wiki/Official_Secrets_Act

Steve · 1 Mar 2009

ban-all-sheds said:
holmslaw said:

Stuff

Click to expand...

http://en.wikipedia.org/wiki/Official_Secrets_Act[/QUOTE]
Shouldnt he have told us this? Why not?

I have to say I'm fascinated by it, I never even considered how those lights work.

ericmark · 1 Mar 2009

During my time on the Falklands I was never asked to sign it. It seems I should have been but some how I slipped the net. So I have no reason why I should not talk about my time there.

But it was some of the old stuff which was very interesting. Phones with crank handles to ring with and generators which were auto start these were years old 1950 to 1960 vintage but would auto start as soon as you switched on a light. Have a job finding one today. They produced about 1.5KVA had a single cylinder lister engine and revved at 1000 revs per min air cooled so would not freeze and seemed to use very little fuel.

Yes they were big but 20 years old used every day and still working could you find a 1.5KVA generator today which will still work in 20 years time?

The generator did the starting no separate starter motor it also charged the battery no separate alternator.

With advent of freezers the old units were sort after as the farmer could go away for a week and each time the freezer needed to cool again the trusty old generator would start and as it switched off so the generator would stop.

Most farms found the 1.5KVA too small a 3.5KVA would just about run a shearing shed but depended on type most used 7.5KVA for shearing shed farm I was at was considered to have gone OTT with a 12KVA generator and here we use more than that to have a shower?

holmslaw · 1 Mar 2009

ban-all-sheds · 1 Mar 2009

ericmark said:
During my time on the Falklands I was never asked to sign it. It seems I should have been but some how I slipped the net. So I have no reason why I should not talk about my time there.

Signing it, or not, makes no difference - it applies either way.

could you find a 1.5KVA generator today which will still work in 20 years time?

If you could it would be made in Japan or Germany, not China.

holmslaw said:
BAS, take the blinkers off, you are being extremely naive. There is a whole world beyond the shores of the UK.

Indeed.

Airfields and runway lighting are built to international standards. Every runway in the world uses the method I outlined above because it is the standard, its about as secret as two way wiring.

Or as GLS lamps, but the wattage used in Civil Service offices is an Official Secret.

To further put your troubled mind at rest I have never worked on runway lighting in the uk, but guarantee it is installled as I described - Heathrow, belfast, manchester, glasgow.

I'm not troubled.

Spark123 · 1 Mar 2009

ban-all-sheds said:
Or as GLS lamps, but the wattage used in Civil Service offices is an Official Secret.

How do they order a replacement lamp?

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Landing Lights

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