Furse Dimmer, 5amp socket Power Question

[woody74]

Given the spelling and grammar, and the nature of the question(s), should this perhaps be moved to "Next Generation"?

 

-w

[billy bobinski]

I'm with John on this one.

 

I didn't serve a four year apprenticeship to start giving advise on this forum on how people should go about blowing themselves up. It has been said before and I'll nick some one else's phrase; If you have to ask about it, you probably shouldn't be doing it!

 

Also, Woody, I half agree with you about it being moved, but in light of a (very) recent thread, now in issues, would that be right as the young chap could be getting all sorts of bad advice on this which is, after all probably more of an electrical & power question?

[GEN]

I only wanted to see if people could point me in the rite direction. Learning from others. I am not useless with this system and I would never mess around with electrics.

 

All I wanted to know is how much power I can have on this system. I always thought I could run more than 8 PAR64s on this system. Now It is an old Furse delta I know that. I have 48 5 AMP sockets. With 1-24 10 Amp fuses inside the dimmer.

[springgrove]

Now It is an old Furse delta I know that. I have 48 5 AMP sockets. With 1-24 10 Amp fuses inside the dimmer.

So it sounds as though you have four 6-way dimmer packs.

 

All I wanted to know is how much power I can have on this system.

I really don't think people can reasonably give you more help until you are much clearer what you have and what supply it is connected to. Try to find someone with more electrical knowledge at your school. We may have come to the point of 'if you have to ask, you shouldn't be doing it'.

 

Nigel

[sleah]

I only wanted to see if people could point me in the rite direction. Learning from others. I am not useless with this system and I would never mess around with electrics.

 

All I wanted to know is how much power I can have on this system. I always thought I could run more than 8 PAR64s on this system. Now It is an old Furse delta I know that. I have 48 5 AMP sockets. With 1-24 10 Amp fuses inside the dimmer.

 

 

GEN

Please don't think anyone is trying to put you down or simply say "Don't do that!". As has been stated electricity is a potentially dangerous thing with serious consequenses if things go wrong. That's not just about messing with wiring or opening enclosures. Simply connecting too many lanterns to a system using readily available parts that are quite safe and legal when used correctly could result in someone being killed or a building being destroyed - it has happened somewhere at some time!!

 

That's why you are being asked for more detailed information, and if you cannot supply that information or don't fully understand the answers, people are saying you should find somebody who does. We all want you to succeed in your activities, but especially want to see you do it safely.

 

You will have gathered from responses so far there is no simple answer to your question, there are several factors involved that have to be considered.

 

Simon

[GEN]

Thank you guys for all your help with this issue so far.

 

Simon I agree with you so thanks for your help. I have a sparky coming in tomorrow, all I need to find out now is the mains supply going to the dimmers which after consulting CCT is not as easy to find as it maybe should be.

 

I have learnt a lot to do with our system just from this thread so again thank you to all the people that have gone out their way to post and help to give me advice on this topic. I am also sorry I couldn't be more descriptive on this subject but I am still learning a lot to do with stage lighting systems.

 

thanks again guys

[billy bobinski]

Hi Gen,

 

I am in agreement with Simon, I may have come across as being a bit harsh, but as he says, there are so many variables in a system to be able to comment on it safely. You (or your school) have done the right thing to get a sparks in. While he's there ask him (I'm sure I wouldn't mind) to give you an overview on the system starting from the main feed to the distribution board mcb's to your dimmers and then out to your lighting bars.

 

If you do that and he explains cable loadings, csa, fuse and mcb ratings and suchlike to you, it will give you a fair idea of how these power ratings are arrived at, and you will know for sure how many lamps you can hang off it. It will also demonstrate the basics of load sharing across your dimmer channels and supplies.

 

You're obviously not afraid to ask, as you have come on here, so don't be afraid of asking a chap who is actually hands on on site. He will be able to tell you volumes more than we can, doing it blind.

 

Hope it helps.

[GEN]

Thanks billy bobinski both you simon and a lot of people of this thread have been very helpful. Thats a great idea I will ask him/her to go through the whole system with me and be taking hard notes as he/she goes along.

 

Thank you very much for you help

[Ynot]

GEN.

 

I will ask the question that I'm sure several have considered asking...

Are you a student or an employed technician at the school?

 

If the former, then AS a student you do not really have the responsibility of assessing what's available to you to use.

That's not to say that you shouldn't use the system (assuming you're monitored by an appropriate teacher) but you should not be put into the position where your conclusions/decisions are taken on face value.

 

If the latter, then ignore the above.

[AndyJones]

I must admit I only skim read this post, so I'm not sure if this has been mentioned before...

 

Just because you can only have 8 pars (or maybe less!) on at any one time, it' doesn't mean you can't have more than 8 pars in you rig.

 

For example you could have 8 pars in red, all on, then 8 different pars in blue which can be on at a different time, As long as you are careful with what you have on at any one time.

 

HTH

 

Andy Jones

[GEN]

Right..... I have just found out that the main feed is rated at 100 amps. The sparky also said that our hall light were feeding off them so ay most id have to allow about 15 amps off the mains feed for these also. This sounds like good news and surely means I can run more than 8 1000w PAR 64's on the system.

[Ynot]

OK....

 

To start with, I REALLY think you need someone to look at this with more of a stage technical head on, rather than a) just taking what the sparks has said and b) asking vague-ish questions here. The sparks may very well be extremely competent at commercial electrickery, but as has been proven time and again, theatre stuff doesn't always feature in their experience - thus there may be hiccups in his assessments.

 

However, pushing on.

 

A 100A single phase can potentially supply a MAXIMUM of 23kW.

If you take off that 15A allowance for the hall lighting, then that drops to just over 19.5kW - so 19 Par 64s.

 

BUT the big question is exactly how many DIMMERS you have - and I'm not sure this has been answered. 48 sockets has been given as the total number of sockets - but these are on the bars, as I recall. You must have some sort of patch panel at the dimmer end, I assume?

 

You then mention 4 dimmers - I take that to be 4 dimmer RACKS (correct me if I'm wrong) which would possibly mean that (if they are 6 channel racks) you will have a maximum of 24 channels to work with, distributed to those 48 sockets by the patch panel I mentioned. Yes?

 

Then we need to know at what rating each dimmer rack is fused/tripped - Unless incorrectly installed, EACH rack must have it's own fuse or trip, which is likely to either be 32 or 63A rated - I would suspect more likely 32A on a 100 max main feed. But you need to KNOW that rating.

 

IF that is 32A per rack, then each rack INDIVIDUALLY could handle just over 7kW, or 7 Par cans.

HOWEVER, you can only run a maximum of 19 overall, so that would mean maybe splitting the lights roughly equally between them.

 

All of this depends on the answers to the above questions.

So - your best bet might be to give us more detail about the school's location, and maybe a friendly Blue-Roomer with the knowledge could pop in and advise....

 

(Oh, and despite you saying "P.s I do know how right is spelt" you've continued to mis-spell it after that statement - at least 3 times to my count. We do really look for decent SPaG here on the BR, which you'll see from the T & C - something a LOT of the regulars will pick up on (and have...))

[GEN]

Ynot thank you for your help and feedback it made a lot of sense

 

I do have a fellow Blue Roomer coming on site on friday but I wanted to see what the sparky had to say as this is what other people have recommended, although I have to say I do agree with what you said with regards to them maybe not knowing theatre installs that well.

 

it is a 6 way Furse Delta loaded with 24 10 amp fuses if that helps?

 

Where would I find out the rating of each dimmer as you mention? 32A does ring a bell! Although I want to double check.

 

With regards to my awful spelling of the word "right" its a really bad habit I guess, I am sorry and will give up from now!

 

Again thanks for your help.

[Tomo]

The fuse in the dimmer for the outgoing circuit is usually a good indicator of the per-channel rating - in this case, it sounds like you've got 10A dimmers.

 

This defines the maximum load you could put on a single channel - a 10A channel can supply a nominal 2.3kW in Europe.

- I'd usually derate that to 2kW to allow for the supply voltage to actually be higher than the lamp is designed for.

 

However, this doesn't tell you anything about the maximum load you can put on the whole dimmer pack - that's limited by the individual supply to the dimmer pack, and the internal design of the pack.

There will always be a 'supply' circuit breaker or fuse somewhere, usually one for each dimmer pack, although not always.

Upstream of those will be further circuit breakers or fuses, right back to the main incomer(s) for the building.

 

The rating of each fuse or circuit breaker gives you the total maximum current you can draw from the dimmers, ring mains and other sockets and items it supplies. (Assuming a competent installation)

 

As previously mentioned, this doesn't mean the 'maximum plugged-in load', it means the maximum that you can turn on at the same time.

 

I have done some shows in venues where there is an ammeter in the control booth with a big red line on it - stay below that line, or suffer the consequences!

- This has meant 'riding' the fade times to keep nicely below, as a 'snap-to-full' would have surged above the maximum and potentially blown the incoming fuse(s).