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FrozenGate by Avery

BIG capacitor bank

The hardware stores arounf here want $20 for an 8' section of 1/2" pipe!

And no trevor, normal sized wire will likely explode, and I don't have 2ga wire.

Hrm, maybe tractor supply has reasonably priced aluminum stock...
 





Flat aluminium bars can be found where they sell windows and doors frames (the ones made in aluminium, ofcourse :p), if you can't find them on your local hardware store ..... or also, angular profiles can work (the ones used for cover wall corners in some cases).

Just remember to sand away the anodization layer from the contact points, sometime is insulant.
 
Aluminium won't have electrical characteristics as good as copper, but if you can't find copper, I suppose its your next best shot. The local hardware stores around here all sell flat aluminium stock. Not sure of the pin spacing on your capacitors, but it comes in a few sizes. You could even cut a strip in half and stack them for more current handling.
 
You just need more Aluminum to have the same current capacity as Copper. 10mm diameter Aluminum has far less resistance and can carry a lot more current than 2mm of copper.
 
I ended up getting some aluminum stock at tractor supply. It cost me $30 for enough to make 80% of the busing, and I need to go back and spend another 10. Not too bad really, but more than I'd like to have spent.

As for copper stock, that stuff can't be found anywhere.



@Cyparagon Remember it's best to have a flat busbar rather than a thick one due to the skin effect.
 
Naah ..... think better ;)

skin effect is related to high frequency, more the frequency is high, more the skin effect is intense.

But, also if the discharge is a pulse, is a high current DC pulse, not a frequency ..... here is the thickness (total cross-section, if you prefer) that count more.
 
But the shorter the pulse, the higher the frequency (even if it is just one cycle) right?
 
I should be able to get copper tube from my local hardware shop - They stopped selling ammonium nitrate to any tom dick and harry a while ago (anfo bombs) but we can still get tubing. I also found a huge hockey puck SCR for firing. Just need to make a mount for it. has a 17,000 kA pulse rating :D

So looks like I am going for a solid state trigger. What are you going to trigger yours with Grenadier?

My IRF540 Mosfets turned up yesterday. I'm expecting 2-3 weeks for delivery of my boards (ordering them this week before I go get my copper). Grenadier, do you want one of the boards and some mosfets?

edit: I found a box for the remote console (this will control everything remotely from the bank - contactors, charging, bleeding and firing. :)

R232724-01.jpg
 
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I don't have any SCRs...

Hell if you were interested in x-rays I'd trade you a coolidge tube for that puck at any moment, or a neon sign transformer. My bank would explode a stud SCR so I need a puck, while yours could be used with a stud.

@Cyparagon
Correct. Skin effect applies to pulses too.
 
Cyparagon said:
But the shorter the pulse, the higher the frequency (even if it is just one cycle) right?
Click to expand...

grenadier said:
.....
@Cyparagon
Correct. Skin effect applies to pulses too.
Click to expand...

Uhm, half and half :p

Skin effect is due mainly to interaction of alternate current and magnetic field in the conductor, so, also if, theorically, a (very very very ..... 1/1000000 s :p) quick pulse can have some appreciable skin effect, a normal DC discharge pulse from a capacitor bank ( milliseconds, or also longer) have technically very low skin effect on the conduction bus bars ..... in this case, that what count more is the total cross section, for the high currents involved (at these currents, insufficent cross section not just risk to melt the wires, but also increase the total resistance of the circuit, slowing down the discharge time).

Other than this, keep in mind that you cannot double the skin of a conduction bar just cutting it in half and paralleling it ..... in fact, if you don't insulate the two bars one from the other, you effectively lower the skin surface of them, doing that ;)
 
vk2fro said:
Remember that thread where i scared the bejeebus out of myself with a charged 160v cap? well guys look what I recently got to play with....

attachment.php


Sitting on the foreground cap is a computer power supply capacitor. The monstrosity its sitting on is 450v 2400uF, so that entire bank is 24 MILLI Farad :) Works out to be just shy of 2.5 kJ.

Heres the charger I intend to get them up to voltage:
attachment.php


Depending on what I want, I can set them up in parallel for 24mF at 450v or series parallel for 900v at 12mF.

Now just need to find a gigantic SCR to fire them - Should be fun launching hard drive platters with a lorentz coil, and of course the old favourite, exploding bits of wire :)
Click to expand...

Can you please fix those pics :D I wanna see how this thing looks like!
 
LaZeRz said:
Can you please fix those pics :D I wanna see how this thing looks like!
Click to expand...

Fixed em - I think I had the photos in the "way to big catagory for the forum" thing, and they got deleted. That or something went screwy with the attachment server.

Either way they are displaying now :)
 
Almost done with the busbars on bank #1. Total is 48 capacitors, and I have about 42 good ones left to make another bank with. I ran out of aluminum to make that one with though, and I'll need to sell another tritium tube to afford it.

I think I'm going to make a pneumatic contactor to switch the cap bank with, as I have some pneumatics that need a good job.
 
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