Driving 1,000 computer monitors?

How?

Actually, what jargon should I use to search for circuits to build.

The background is that I do work for a community group that re-uses old computers and we currently have premises in an arts centre. Our "rent" is basically technical knowledge and assistance to support vqarious "artistic" projects.

This one comes out a project that will be a wall of computer monitors (db15 plug driven) all showing the same image, so my understanding says that we are going to need an amplifier and splitters or splitter-amplifier, preferrably with the least number of stages.

Hence, my question for assistance in what jargon I should plug into search engines.

This is basically for the mathematics of costing the construction of the video splitters, etc.

TIA.

Reply to
Terry Collins
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The proper term is "Video Distribution Amplifier" There are plenty of commercial units, as well as chips designed for this application. The biggest problem will be cable lengths causing roll off of higher frequencies. National. maxim and others make suitable chips for the project.

--
Link to my "Computers for disabled Veterans" project website deleted
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Reply to
Michael A. Terrell

I've seen something like this using TV sets? video monitors? at a shopping centre, only they formed 1 *BIG* picture. I'd suggest it'd be cheaper/easier to use TV's and you'd get the same result.

John Mackesy

Reply to
John Mackesy

"Terry Collins"

** Are you serious ?????

***1000*** monitors ???

The average monitor draws circa 0.5 amps rms from the supply - so 1000 of them means 500 amps !!!!!!!!

Even with 3-phase that load is 170 amps per phase - with no neutral current cancellation !!!!!!!

Monitors have large switch on surges too - circa 50 amps peak EACH !!!!

.......... Phil

Reply to
Phil Allison

You want a video distribution amplifier, and one with the maximum number of outputs possible. Something like this:

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What you want to do is try to minimise the number of cascaded units. So if you have one with 10 outputs, you'll need to casacde an array of 3 of these boxes in series to get 1000 outputs. You have to make sure it can do this at the bandwidth you need. What resolution and frame rate are you thinking of using?, this may have a large impact on the number of units you can cascade without problem. Shouldn't be too hard if you are using a low-ish resolution and refresh rate, say 800x600 and

Reply to
David L. Jones

Umm, this is "art", you know, here today, gone tomorrow, faster than a movie set. so, there is no/absolute minimal budget. (hmm, anyone know of a movie set that needs something like this).

And since we pass on computer monitors, they are "free", plus, the local supplier of "TVs" has just soiled his pants on supplying reliable goods (only 3 out of 20 worked - of course artist didn't test on delivery did he).

So, we have said we can give them to him, one way trip, absolutely no returns will be considered for any reason. This is a future project, so we can pass on our surplus.

Reply to
Terry Collins

He is.

Yep, one of our number has already done this dance, but as I said, it is all just mathematics, HIS.

And we have already had the first discussion session with him and pointed out that he will need to do a lot of calculations on electricity demands, weight and the scaffolding to support it, plus make sure the floor will support it (and no I don't think that your or my welding skills are good enough to make a scaffold), etc, etc,

Well, this is where we can advise him about staging the switch on, but did you mean 5 amp?

Now, the good news is that the hall in which he wants to do it has at least 6 three phase outlets and he knows he has to check circuit numbers, plus he has already asked the site electrician to come and talk to him.

I hope it is in winter, then the concrete mausoleum will not need the 12 radiant heaters is has for this space {:-)

Reply to
Terry Collins

Thanks. Looking at the $$$ I can see this project being radically changed. Well, the last one was to have 20 monitors & x speakers rotating on a clothes line, but it settled for a static wall on TV's {:-).

I don't think it counts as art if you can just buy it. Actually, I personally would not call the project art as it has a commercial solution, but then the "art" may be in what is in the video images.

And good learning for me. {:-)

I can hunt around and see what I can find. I don't mind doing a bit of investigating for amusement, but the materials for trialling will definitely be funded for this, besides I already have my video splitter {:-).

Reply to
Terry Collins

"FruitLoop" "Phil Allison"

** You must be a mug electrician as well as a fruit loop.

The rms value of the neutral current when the load wholly electronic is

1.73 ( sqrt 3 ) times the phase currents.

The is simply no cancellation in the neutral.

........... Phil

Reply to
Phil Allison

neutral

neutral

Na , Im a rocket scientist , more interesting than a lowlife electrician

What about the 120 degree phase seperation . Also I have seen 3 phase power single phase systems with the neutral fully floating and not connected . For this to work a balanced 3 phase load is required + a common star point connection on a transformer . So go root your boot a neutral isnt even required .

Reply to
FruitLoop

"FruitLoop" = one king size, moronic pig

** Must be one of them former Nazi types - eh ???

** No point even trying to inform this anencephalic POS about anythig.

Wanna bet the anonymous cretin is an apprentice ???

.......... Phil

Reply to
Phil Allison

And your normal , hahahahahahahahahaha

Yep even a modern day apprentice is smarter than you phillis . Hahahahahahaha

Reply to
FruitLoop

Phil's post seems valid to me.

This article mentions the non-balanced neutral problem.

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3 phase balancing works when the loads draw sinusoidal current. Computer monitors have bridge rectifiers across the mains input, which charge capacitors with short pulses of current near the peaks of the sinewave. So the phases see large amplitude, narrow current pulses - at 120 degree timing with little neutral cancellation - so the neutral wire is working very hard.

Roger Lascelles

Reply to
Roger Lascelles

"Roger Lascelles" <

** In any case, the only time the neutral can be left floating in when the 3 phase load is ONE device.

Where multiple, single phase devices constitute the total load, each with thier own switches, fuses etc it is utterly out of the question.

.......... Phil

Reply to
Phil Allison

Apologies for the unorthodox method of approaching the subject, but I think I have met you in the company of Dan, Grant, Mark, et al.

If you are who I think you are, would it be possible to get one of them to contact me, pls? Perhaps, Grant or Mark? Pls note that I have emailed them using a new email address.

Thanks.

Reply to
Moses Lim

You never know in a big city like Syd-na-nee :) Know a guy who built a 24:1 pulley system for special fx - gun shots, falling off bikes, etc

Reply to
Moses Lim

Computer

So

the

Phillis , try it yourself get a 3 phase load , all independant , roughly balanced ( like me ) and then connect all the neutrals to create a star point , but dont connect to a neutral . It WILL work .

Reply to
FruitLoop

This question is really obvious which is probably why no one has asked it, but why not LCDs? The extra expense might be saved on what sounds like expensive power considerations and scaffolding.

Michael

Reply to
Michael C

"Michael C" ...

** Because he already has 1000 CRT monitors - old, discarded ones.

Read the damn thread.

.......... Phil

Reply to
Phil Allison

A balanced three Phase load is completely irrelevant to the current topic - that is 1000 Computer monitors being connected to Mains. I am afraid that Phil and Roger are quite correct Computer monitors do not draw Sinusoidal current rather they draw short pulses of current near the peak of each Sine wave. These Pulses on different phases come nowhere close to cancelling each other out.

Reply to
Richard Freeman

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