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Registered Member #2810
Joined: Sat Apr 17 2010, 07:17PM
Location:
Posts: 22
Hey Everybody! This is my first time posting here and I know this question has been asked many times before but I have looked all over the web and in older posts on this site but I still haven't been able to find exactly what I'm looking for.
so here's the deal:
After a starting a few years ago on my coilgun (yes, a few years-mainly due to the fact that the guy who was helping me wasn't very reliable, and I was busy with school and low on funding), I finally have a working prototype. But I have hit a major Snag: I can't find somewhere to buy More Capacitors!
So here's where I need help: I need Capacitors. None of this disposable camera cap stuff, but REAL Capacitors. I would like to have my cap bank reach at least 5KJ. Unfortunately, alltronics is outta their famous 3900 uf 400v caps (otherwise I would have bought about 50). I am considering buying 2 of these but the fact that they are 225 lbs each is kind of a deterrent(Esp with shipping and transportation but I will buy them if I don't find anything better):
If anyone has any recommendations about sites where I can buy some good caps without paying through the nose (like you sometimes do with digikey) I would greatly appreciate it. If I could find some similar to the 400 v 3900 uf alltronics ones at not more than....say....$20 a pop that would be awesome. Or if anyone knows of sites where I can buy high voltage pulse capacitors that would be very helpful.
Registered Member #1451
Joined: Wed Apr 23 2008, 03:48AM
Location: Boulder, Co
Posts: 661
I wouldn't get the pulse caps for a coilgun... The pulse would be WAY to fast for that. You would need an insanely large coil to get the same rlc time constants.
Ebay is always a great place. A while ago there were a lot of the caps you are looking for on eBay, lots of about 10... Here are some 400v 1000uF ones, but they are a little smaller than you wanted.
I ordered some from theses guys, bad communication skills but I got them in the mail (postage cost me $40 from US to Aus =\ but still cheaper) and the are in okay condition, they have some minor dents. I haven't charged the caps up but they look pretty good.
Registered Member #2810
Joined: Sat Apr 17 2010, 07:17PM
Location:
Posts: 22
Thank you all so much! Thank you Turkey9 for the advice cause I was about to buy some of those huge caps but pulse length was something I hadn't thought about. Also, Special thanks to nicko and ghostnull for the caps. I was so eager to finish this project that I went ahead and bought 50 of those caps so my bank should be well over 5kj-gonna have some fun!
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Capacitor Help
I want some too 
and I hope to see your coil gun here soon 