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Firing failure-partial


Wookiecj

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Hello all, newbie to the blue room here...

I've been doing amateur dramatics for 30+ years and have used the Le Maitre system many times to manage up to a dozen pyro flashes, usually the small, low smoke flashes but sometimes gerbs and confetti cannon so I'm not really a newbie to small stage pyro effects...

I'm working with an experienced magician (magic circle member), who has been on Lincoln's course recently, using an MSQ 12 controller that he has purchased. We successfully used it to fire a smoke cartridge during our set-up today but had a partial failure on a string of 8 electronic matches wired in series. Only the 8th match detonated i.e. the one closest to the control on the 'negative' wire. We were using pyro splicers to connect electronic matches sitting at the bottom of custom made stainless steel flash pots with a copper chimney to direct the direction of 'fire' which was effected using flash cotton under flash paper to produce a flame which travelled about 20inches.

Now, to my way of thinking, the circuit must have been correctly wired for ANY of the effects to fire...

However, I am prepared to believe that if there was any lag in the current reaching the matches then the fact that, as one fired, the rest of the circuit was disrupted. Could this be the case?

What is puzzling though, is the fact that only the effect on the 'negative' side of the circuit activated NOT the one on the positive side...

Your thoughts would be appreciated. Thanks.

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My pyro knowledge is limited apart from running a home made pyro system years ago before it was dodgy to make your own kit I used to fire smoke puffs for a rock band

My homemade box was set to fire 4 individual circuits singly or together on one fire button

My theory would be that the first blew but that lost the circuit to the others?

Does it normally work or is this the first fire?

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The position in the circuit of the igniter which fired is irrelevant.

If you're wiring igniters in series, and they're not of the same type (or sometimes even from the same batch, if they're cheap and cheerful ones) it's likely that the difference in the way that they respond will result in one firing and disrupting the circuit before they've all gone. Were you using identical igniters? If not, it's safer to wire in parallel - more chance of getting them all to go.

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IMO (and only that) --

8 igs in series may be beyond design spec for the controller, -read the book.

the batteries may be old or well used and fail to deliver their peak current.

Was it really wired correctly? I've seen several attempts to wire in series all very varied.

 

Given a combination of low battery condition and lots of igs in series, I suggest that all may have passed current but one fused first, cutting power to all the rest, this may be due to mixed batch numbers for the igs or simply that the current available was low so they fired slowly and one fired first.

 

To fire ten cues in series 1/ I'd look for a firing box rated for 20 cues, 2/ I might set up as two series cues of four, wired in parallel, 3/ maybe I'd look for fatter connection wire, Maybe I'd get black wire Davy -bickford igs rather than orange wired cheap (and variable, Chinese) igniters

 

 

Wire it all up again, there's no need to fire it(!), use a digital ohm meter and see what the reading is, With bell wire assume an ohm per 10m of wire and an ohm for each igniter So you are at about 10 ohms, that's beyond one PP3 battery, and at the limit of two.

 

LeMaitre's www says "It is advised that no more than 5 effects are fired from one channel,..." for the 12 channel sequencer, and that 8 devices can be fired from a 2 or 6 way controller channel.

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Hi, So I am the other guy that WookieCJ was working with yesterday. We did wire it correctly and have double checked both with the manufacturers instructions, Le Maitre instructions, the suppliers instructions, plus others found on the web, all say the same thing. The instructions say that with the materials purchased you can fire up to 100 electronic matches in series, although distance is a factor and you have to reduce the amount of ignitors per cue, but 8 over 20 ft should be no issue, confirmed that all igniters were from the same batch, I think the issue is, as Jivemaster pointed, out poor batteries were to blame, they started out indicating 12V on the display and fired the smoke wired approx. 50 feet cable length (shooting wire Heavy Duty), the issue on checking after the 1 fire and 7 failures the display showed only 8.9V. So a new external 12v supply fully charged will be used this afternoon, we will keep you posted

 

Thank you all for your help and assistance very appreciated.

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To achieve reliable multiple series firing, you need to (a) ensure all igniters are the same type and (b) you need to able to push enough current round the loop for long enough; so in other words, if you are using a 'discharge' firing system it needs to store enough energy to achieve this and if you're using a 'battery' system, the voltage needs to be high enough (without 'sag' under load). As an example, this document from Davey Bickford is worth a look; they suggest that whilst the 'all-fire current' for a single igniter is only 0.6A, for series igniters, the system should be able to supply 1A per igniter - a bit on the high side in my experience, but you get the idea.

 

http://www.knk1301.eu/_source/links/electricigniters.pdf

 

If these conditions are not achieved, the fusible wire in the igniters will heat up too slowly and one will ignite first, breaking the circuit as you have experienced.

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...using an MSQ 12 controller...

 

 

...double checked both with the manufacturers instructions...all say the same thing...with the materials purchased you can fire up to 100 electronic matches in series...

 

Is this the controller you have?

 

post-207-0-23789700-1497861416_thumb.jpg

 

http://www.rfremotech.com/MS12Q2BSeries.html

 

That unit takes 6 x AA batteries to give a firing voltage of 9 volts. That is not enough to reliably fire 8 devices in series let alone 100.

 

 

 

 

Brian

(one of the team who delivered the course you were on)

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...using an MSQ 12 controller...

 

 

...double checked both with the manufacturers instructions...all say the same thing...with the materials purchased you can fire up to 100 electronic matches in series...

 

Is this the controller you have?

 

post-207-0-23789700-1497861416_thumb.jpg

 

http://www.rfremotec...2Q2BSeries.html

 

That unit takes 6 x AA batteries to give a firing voltage of 9 volts. That is not enough to reliably fire 8 devices in series let alone 100.

 

 

 

 

Brian

(one of the team who delivered the course you were on)

 

Hi Brian, Yes that is the controller, and I bow to your knowledge, their website is very misleading then...

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...their website is very misleading then...

 

A misleading Chinese website? Surely not!

 

If you need multiple devices to fire together you might get away with a mix of series and parallel. For example, connect up 4 pairs of series wired devices in parallel. The igniters in each series pair would need to be of the same type, and you'd lose the ability to easily test, but you'd stand more chance of getting it all to go. The other option would be to use an external power supply if you don't need to be battery powered. An 18v external supply would help.

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...their website is very misleading then...

 

A misleading Chinese website? Surely not!

 

If you need multiple devices to fire together you might get away with a mix of series and parallel. For example, connect up 4 pairs of series wired devices in parallel. The igniters in each series pair would need to be of the same type, and you'd lose the ability to easily test, but you'd stand more chance of getting it all to go. The other option would be to use an external power supply if you don't need to be battery powered. An 18v external supply would help.

 

It is a UK company www.EasyPyro.com

 

 

 

 

 

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Although I'm sure when I was on Linc's course last year we series wired about 30 igniters and fired them all from a Le Maitre unit, and they all went off.

 

You did and the hand-held controller used only has a 9v battery in it. It does however step that up to around 300 volts internally and use that to charge a capacitor whose stored energy is then dumped into the connected igniters.

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Although I'm sure when I was on Linc's course last year we series wired about 30 igniters and fired them all from a Le Maitre unit, and they all went off.

 

You did and the hand-held controller used only has a 9v battery in it. It does however step that up to around 300 volts internally and use that to charge a capacitor whose stored energy is then dumped into the connected igniters.

 

Exactly, which brings us back, as ever, to using the right tools for the job.

 

PP3, hmmm ...

 

Capacitive discharge unit designed for the job, oh yes.

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Capacitive discharge unit designed for the job, oh yes.

 

If anyone is looking for a hand-held cap discharge unit at a decent price, I use one of these...

 

http://www.feuerwerks-zuendanlagen.de/frontend/scripts/index.php?groupId=102&productId=15&setMainAreaTemplatePath=mainarea_productdetail.html&query=

 

...it lacks a key switch but there's enough room to add one easily.

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