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 Post subject: Stage lighting
PostPosted: Wed Oct 10, 2007 9:32 am 
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Hi,

Last night on James' request, myself & some of the Dorkbot crew had a look at the lighting gear on the balconies. This is what we found out... don't know how much of this was known already.

We have sorted out the working lights from the dead ones, there are eight working in total and these are now all on the two lighting stands. All of these are connected to the large mixing desk, which does seem to work fine.

There are only six channels on the distribution box, two sockets each, so some channels run two lights. Which is which can be swapped around by just shifting the plugs around.

There is a second distribution box with another six channels. This needs an adapter to plug it in to a standard mains socket. If this can be done, it can also be hooked up to the mixing desk and some of the lights transferred to it, so that every light is individually controllable.

There is one spare bulb taped to the mixing desk, which we took from a light which wasn't working, though the bulb looks intact. It may be possible to put this in one of the housings in the "dead" pile (at the far end of the balcony) to get another working light.

The bulb we took out was rated at 500W. If this is the same as in all the lights, it means each will have a current draw of 500/240 = 2.1A and so six lights can just about be run simultaneously on a 13A circuit.

If each of the two distribution boxes is hooked up to a separate and dedicated 13A circuit, or both to a dedicated 30A circuit from the main fuse distribution board downstairs, it should be possible to use the lights in any combination without worrying about blowing things.

Hope this helps!


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 Post subject:
PostPosted: Wed Oct 10, 2007 10:24 am 
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Could the second distribution box (we call them Dimmers) just have the big plug pulled off and a 13 amp one added safely on a permanent basis?

I've done this before, but in the back room of a pub as an emergency on some hire equipment with a chocolate block and lots of electrical tape.

That's great about the big board working, thanks ....


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PostPosted: Wed Oct 10, 2007 11:33 am 
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I am a little concerned with altering electrical appliance fuses. If we use an incorrect fuse this can lead to possible electrocution from power surges bigger than an appliance is used to handling if we use fuses that are too high and fire hazard from overheating plugs if we use fuses that are too low.

It's a while since I studied electrics but I have some horror stories from old friends from uni about fuck ups after messing with fuses. I am sure that someone is better qualified to judge - but I think we need to ensure that all fuse changes are ok'd by someone who is qualified to do so.

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 Post subject:
PostPosted: Wed Oct 10, 2007 12:42 pm 
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James - yes, that should be possible as per the other one. It has big 30A cable on it though so it may be necessary to replace that with a fresh 13A cable to take the new plug.

Laura - I'm keeping track of all the current levels and fuses here, don't worry. We'd be running each dimmer at under half its rated capacity, to ensure it's okay to run from a 13A circuit, wiring, plug and fuse.

James - do you know if there are two separate 13A or higher circuits available nearby? I'm guessing all the sockets there are on the same one.

We've got to rewire the new meeting room in the near future, so we could just take the opportunity to run 30A cable right from the main distribution board at the same time. Might cost a bit though.


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 Post subject:
PostPosted: Wed Oct 10, 2007 5:14 pm 
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I understand the concern ... the Dimmers are big beasts, and can quite happily draw far more than 13A. So there is no danger of us over powering the actual dimmer. There is a danger of us melting the 13A wire and plug, and this is why it absolutely will have a 13A fuse in it. (Although given the current lights we have and the current load we can draw, we shouldn't have a problem, but the fuse will definitely be there as a safety.)

Main rings, we need to look at this closer ... I don't know for certain. It wasn't a issue in August but with extra lights it might become one and its better to find out first.

If we have a forest person who's a trained electrician, I'm happy to show them round and get their advice ...


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 Post subject:
PostPosted: Fri Oct 12, 2007 11:34 am 
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The lighting board doesn't entirely work - channel 6 on the grey sliders is out. I'll make a full list of what's broken after this weekend.


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PostPosted: Sat Oct 13, 2007 10:26 am 
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I can't remember which the grey ones are - does that mean channel 6 isn't working at all (it did for us) or just some of the sliders don't work? If the latter we may be able to fix it, possibly cannibalising some bits from the little one.


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 Post subject:
PostPosted: Sat Oct 13, 2007 10:37 am 
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Dont canabalise bits from the little one - we always need a board that works, something simple ... we should keep it as backup. Plus it might be good as a focuser. (For focusing lights, you sometimes have to run a long way from the board to the lights. If you can have a wee board on a long extension you can take where you are it saves time and energy)

Instead, seeing the main board has 3 groups of dimmer controls, but we only have two dimmers and not enought lights, and the fact we are unlikely to get more, canabalise bits from the 3rd group to make the 1st two groups work perfectly.

Channel 6 works on the white top slider but not the grey bottom slider. It could be the grey A/B switch, which has the cover missing and is unmovable. I'll make a full list this week.


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PostPosted: Sat Oct 13, 2007 6:06 pm 
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Okay, will do.


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 Post subject:
PostPosted: Thu Oct 18, 2007 11:30 am 
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right. Some of it is outright broken, but a lot of the sliders dont run smooth. ie when you try to fade a light up slowly it flashes all over the place.

I'm hoping the board just needs to be taken apart and given a really good clean inside. There is a big bit of bird shit across it, after all. :-)

I don't mind doing this, unless one of the Dorkbot guys wants it as a project?


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PostPosted: Thu Oct 18, 2007 12:06 pm 
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Maybe you could give it a clean out and see how that goes? If there's still problems after that, next Dorkbot is scheduled for 13th Nov, or I can just have a go at it myself at some point.


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