Capacitors

[MEMPHIS91]

Hey guys, First off thanks so much for you help on my last few problems. The firework show I did went perfect! I had 500 people show up and no one died. lol

My new problem comes from a brain storm of an idea I had. I am making a small 200 cue pin board to manual fire some new fireworks. But the wire need to run it is gonna cost me alot of money due to the fact the im running 24VDC through 200 feet of 18AWG wire. So do the math and see that 200 feet x 200 cues = ALOT!! So my idea is to use a smaller wire and use capacitors to send more power down the line.

So what i need is a capacitor that can charge on 24VDC and then send MEGA power out through 200 feet of 22AWG wire. It needs to be able to charge kinda quick because some of these cues fire about a second apart. And I may have to use more than one and have it switch to give the others time to charge back up.

I have no idea about any thing to do with them, so treat me like a 5 year old. lol

Thanks so much again guys. Yall have been AWESOME!

 

[ronsimpson]

I need to understand. You run 200 wires of #18 or #22. This is 200 feet away from the power source. There are 200 switches.
(?)

 

[MEMPHIS91]

Well I can fire it right now using the #18, but I want to save money and use #22, that's the reason for the Capacitors. And yes 200 feet away from power source and 200 switches. But only 2 switches will be used at once.

BTW I'm using 34 Gauge Nicrhome about 1-2 inches long. That's what the load is. But I need to be able to fire several at once. =D

 

[ronsimpson]

If we added some barins to this:
Run two large wires fore power and two small wires for signal.
Have a 200 switch board that sends commands.
Have a 200 relay board that receives commands and closes the correct contact.
What do you think?

 

[MEMPHIS91]

Done that. Tired that. I want something that I don't have to use relays or PCBs on at all. So that I KNOW everything will work perfect.
Plus I really like the capacitor idea.

 

[ronsimpson]

I do not see a way of doing what you want with capacitors on this end of the wire.

If you had very very small wire it can not supply enough power to light the NiChrome wire. One option is to put the capacitor on the far end of the wire. The capacitor will charge over time and now this power is at the other end. Then through a switch on the far end that power can be used to light the NiChrome.

Idea two: I have a problem much like this. I need to drive a 24 volt load over 300 feet away. I am using parallel printer wire which is small. I am using 30 a volt supply. About 6 volts are lost in the small wire and that puts 24 volts on the far end.

What is the current to light the NiChrome wire?

 

[MEMPHIS91]

The current is very very small. That's why I think the Capacitor would work. I know people make systems like this. And they use capacitor on the switch end of the wire.
So I know it can be done. I just need to know how.
All it has to do is dump a huge load into the wire. The Nichrome will burn before the #22 wire does.

 

[MEMPHIS91]

https://www.pyromate.com/black-magic.htm

 

[crutschow]

Capacitors only reduce the apparent impedance of the power supply to transient currents, they will not increase the current through the wire if the supply is able to supply the current already.

One way to get more current though a higher resistance wire is just to use a higher voltage supply. According to my calculations the nichrome wire has a resistance of about 20Ω and 400' of 18AWG wire has a resistance of 2.55Ω. The current at 24V is thus 24/22.6 = 1.06A. 400' of 22AWG wire has a resistance 6.45Ω. Thus to get the same current you would need to increase the voltage by 1.06*(6.45-2.55) = 4.14V or to 28V. Can you do that?

 

[MEMPHIS91]

Im not trying to keep the same voltage or current. In fact i'm trying to make current go down, and increase the voltage. Follow the link. They use a 9V and make 250V. So im trying 24V and trying to get about the same.

 

[ericgibbs]

Im not trying to keep the same voltage or current. In fact i'm trying to make current go down, and increase the voltage. Follow the link. They use a 9V and make 250V. So im trying 24V and trying to get about the same.

hi,
Your link explains the step up to 250Vdc to charge the capacitors in order to fire the remote e-matches.
Why dont you use the same method.?

 

[MEMPHIS91]

Oh, I thought the Capacitor is what stepped it up.... hmmm..... So what do I need to use to step it up?

 

[ericgibbs]

Oh, I thought the Capacitor is what stepped it up.... hmmm..... So what do I need to use to step it up?

You could buy a commercial 24Vdc to 230Vac converter, say about 50Watt, rectify to 250Vdc.

Are the 200 circuits fired electronically or by manual switches.?

 

[MEMPHIS91]

Pin board, so manual switch.
And explain more about the converter? Can you show me part numbers?

 

[buteman]

I think that from what I have read from the link that the 250 volt output from the unit pushes a very high current through the wire. Now this is probably fine as long as the wire you use can handle this current for longer than the nichrome wire because they will both start to heat up rapidly. i expect that during the time the capacitor is discharging it will not be connected to the circuit which charges it up so it will discharge rapidly and so the current will fall rapidly also. You would probably need to use several capacitors each of which can be kept fully charged until used so that after each use they are put back on charge.

 

[MEMPHIS91]

I would like to be able to have it always connected to power, Or make some kind of switch board that swaps capacitors after one is drain and reconnects it to power.

 

[buteman]

Just a thought, if you are going to be using a voltage as high as 250, you are talking about lethal voltages, especially if the capacitor is connected all the time.

 

[MEMPHIS91]

True,,,, hmmm.. ill be carefull lol

 

[ronsimpson]

Do you have a part number on the Nicrome wire?
How many e-matches will you connect in series. (how many will you light at one time?)

 

[ronv]

You might try the flash card out of a disposable camera. If that works you could go from there to reduce the charge time.