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| starman |
 Posted: 06/20/2008 12:04 PM Post subject: |
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Big Daddio
Joined: 11 Dec 2007
Posts: 1744
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| Ragnarok wrote: |
Actually, copper pipe is very popular for high power electrics, because in addition to having a low resistance, you can run cooling water through the middle to stop it from overheating, allowing you to put even higher currents through it. 
With a sufficently hefty water pump, I could force thousands of amps down a piddlingly narrow piece of copper pipe, yet still keep it cool to the touch.
It's fairly common to do so on induction heaters. |
I've worked with and around electrical installations in the US for many years and have never seen copper pipe used electrically for anything other than a ground tap on a cold water pipe. I'm sure it has usage in more esoteric applications, just not out with the common folk.
5 - 10' copper rods are standard use for ground stakes but that isn't a pipe.
Again I ask, why not just use copper buss products that are designed for electrical usage? The telephone industry is awash with plate copper bussing that is used in switching rooms. |
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| rp181 |
| Posted: 06/20/2008 12:20 PM Post subject: |
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Lieutenant Colonel
Joined: 13 Dec 2007
Posts: 467
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| Quote: | 5 - 10' copper rods are standard use for ground stakes but that isn't a pipe.
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Those rods arnt copper, but rather steel rods coated with copper. I've used some as a projectile
Copper bus bars are more expensive than pipe in terms of surface area, which is important for this. The copper will only be conducting a short pulse, so cooling isnt really a problem. I've seen some shows that used induction heaters to melt steel, and it was a water[?] cooled tube. |
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| starman |
| Posted: 06/20/2008 12:30 PM Post subject: |
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Big Daddio
Joined: 11 Dec 2007
Posts: 1744
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| rp181 wrote: | | Quote: | 5 - 10' copper rods are standard use for ground stakes but that isn't a pipe.
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Those rods arnt copper, but rather steel rods coated with copper. I've used some as a projectile . |
Yes I'm aware they are plated...  They are still extremely effective conductors overall.
| rp181 wrote: | | Copper bus bars are more expensive than pipe in terms of surface area, which is important for this. The copper will only be conducting a short pulse, so cooling isnt really a problem. I've seen some shows that used induction heaters to melt steel, and it was a water[?] cooled tube. |
That would definitely qualify as esoteric usage.
It seems to me the context and scope of your project doesn't lend itself well to doing things much on the cheap. Since you're dealing in the high joule world, whatever you construct, be sure you keep the chewing gum and bailing wire aspects way down...  |
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| jimmy101 |
| Posted: 06/20/2008 12:49 PM Post subject: |
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Major General
Joined: 28 Mar 2007
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The copper pipe should work great except for perhaps two problems;
1. Making connections. Anything you connect to the pipe needs to do so through a cross sectional area about the same as the x-sectional area of the pipe.
2. Galvanic reactions. A large surface area between the copper and say steel screws will create a battery. The copper will slowly corode and start to loose contact.
I would think both problems are fixable. |
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| ramses |
| Posted: 06/20/2008 13:11 PM Post subject: |
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Staff Sergeant
Joined: 29 May 2008
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The pipes should work, once you find a way to mount them on the terminals. They will have slightly higher resistance than electrical copper, and a higher inductance. They shouldn't vaporize, though. I am running doubled up aluminum sheet on my 3kj bank and nothing has even gotten hot (except for the 26 AWG steel wire i expected to carry wall current for the charger  ) the skin effect isn't even as bad as you think:http://daycounter.com/Calculators/SkinEffect/Skin-Effect-Calcula tor.phtml
you can i think.
you can figure out your frequency with this:http://www.coilgun.info/mark2/rlcsim.htm
hope that helped! |
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| rp181 |
| Posted: 06/20/2008 16:55 PM Post subject: |
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Lieutenant Colonel
Joined: 13 Dec 2007
Posts: 467
52.76 Spud Bux
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| Quote: | | It seems to me the context and scope of your project doesn't lend itself well to doing things much on the cheap. Since you're dealing in the high joule world, whatever you construct, be sure you keep the chewing gum and bailing wire aspects way down... |
Naa, im not trying to be cheap, on mcmaster a 6x24" sheet .02"thick is 17$, i planned to use two strips for each bus bar, insulated by teflon film. I also plan to stay away from cheap, as some companies have already donated some stuff. |
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