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[moved] 24,000j Capacitor Bank (Now Complete)

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Tesladownunder

Fri Apr 24 2009, 02:09AM

Registered Member #10 Joined: Thu Feb 02 2006, 09:45AM
Location: Bunbury, Australia
Posts: 1424

FastMHz wrote ...

It'd be rather neat if I could get a *low cost* accelerometer

Silicon based accelerometers running to 5g wont do it. The forces are acting only over a few cm and must be in the order of well over 20G. Hard to measure as metal will deform at these forces and reduce the acceleration.
Simplest to measure kinetic energy gained is to use a variant of the ballistic pendulum. Basically see how high it flies and do the simple physics. If it is a light object like a drink can and air friction is an issue, fire it into a heavy padded object that will catch it and see how high that goes (momentum is conserved).

Secondly, I am still concerned about cap failure. I bet you didn't fail with 24kJ charged. Probably cap failed on the reverse ringdown when a lot of the energy is gone then was short when charging was attempted so didn't reaccumulate.
24kJ into single cap = b o m b

FastMHz

Fri Apr 24 2009, 04:34AM

Registered Member #179 Joined: Thu Feb 16 2006, 02:08AM
Location: Hagerstown, Maryland - Close to Prime Outlets
Posts: 287

Actually, failure occured during charge....what a surprise that was, blew through the lexan cover and all.

Not sure that any electronic accelerometer would survive these forces, or the EMP. I think the 'ShockWatch' may be my answer...or video analysis. I should get Discovery's TimeWarp to do a segment on my launchers!!

Finn Hammer

Fri Apr 24 2009, 04:59AM

Registered Member #205 Joined: Sat Feb 18 2006, 11:59AM
Location: SkÃ¸rping, Denmark
Posts: 741

FastMHz wrote ...

Actually, failure occured during charge....what a surprise that was, blew through the lexan cover and all.

Not sure that any electronic accelerometer would survive these forces, or the EMP. I think the 'ShockWatch' may be my answer...or video analysis. I should get Discovery's TimeWarp to do a segment on my launchers!!

I have a 2kJ disk launcher.
I launch 4" dia. by 3/4 inch thick aluminum slugs with it.
They fly 20 meters into the air. Haven't measured it, but I estimate like that.
Thick discs is the key to high flying objects, in my opinion.

Cheers, Finn Hammer

FastMHz

Fri Apr 24 2009, 08:54PM

Registered Member #179 Joined: Thu Feb 16 2006, 02:08AM
Location: Hagerstown, Maryland - Close to Prime Outlets
Posts: 287

I found that as well, thicker seems to work better than thinner....the only problem is thicker ones come down harder too :-o I have 1/4" on my bucket, a 11" diameter 1/2" platter might weigh so much that it'd cancel out the gains...if only I had a chunk of aluminum that big to try.

Tesladownunder

Tue Aug 11 2009, 12:37PM

Registered Member #10 Joined: Thu Feb 02 2006, 09:45AM
Location: Bunbury, Australia
Posts: 1424

Is there any more news on the launcher. Caps still functioning? Things launched etc

FastMHz

Fri Dec 25 2009, 06:13PM

Registered Member #179 Joined: Thu Feb 16 2006, 02:08AM
Location: Hagerstown, Maryland - Close to Prime Outlets
Posts: 287

Yes, the system is still operational! I have yet to launch the bucket from the giant coil as other things have taken priority, but it will happen! On the other hand, the bank has been utilized for purely entertainment purposes a few times as can be seen in my YouTube videos. Regards

teravolt

Mon Dec 28 2009, 08:21AM

Registered Member #195 Joined: Fri Feb 17 2006, 08:27PM
Location: Berkeley, ca.
Posts: 1111

nice work FastMHz, I am surprized that the caps haven't shorted between the cans yet. I wanted to try this expieriment but using 6 scrs with 6 banks in seqence but I got nevice because if 1 bank fails the others will dump into that one bank. are you using gradeing resistors? can you poast a link to your youtube vid. thanks NB

FastMHz

Mon Dec 28 2009, 06:19PM

Registered Member #179 Joined: Thu Feb 16 2006, 02:08AM
Location: Hagerstown, Maryland - Close to Prime Outlets
Posts: 287

All my videos can be found here:

http://www.youtube.com/fastmhz

And technical information is on my blog:

http://www.fastmhz.com

Hope everyone had a spectacular holiday!!

RogerInOhio

Wed Dec 30 2009, 02:05AM

Registered Member #1034 Joined: Sat Sept 29 2007, 12:50PM
Location: Chillicothe, Ohio
Posts: 154

Hi Ceyn, I love your pancake coils. That is really a neat way to launch things. One thing I was wondering about though is if you discharge your capacitor bank into an inductive load doesn't the thing oscillate causing the capacitors to get charged in the revers polarity and wouldn't that be bad if they are electrolytic capacitors?

One more question. Have you noticed if the conductivity of the disk being launched makes much difference in how high it goes ? There is a good demo at the end of this video

where a washer is cooled with liquid nitrogen before launching and it seems to help a lot.

Roger

FastMHz

Wed Dec 30 2009, 04:22AM

Registered Member #179 Joined: Thu Feb 16 2006, 02:08AM
Location: Hagerstown, Maryland - Close to Prime Outlets
Posts: 287

I'm sure it does ring my caps, but I don't seem to be having a problem. The bank hasn't seemed to have weakened despite hundreds of pulses into coils and other objects.

I'm sure a super-conductive disc would be better, however there is also the issue of this amount of energy deforming them - a super-cooled disc might explode or at least crack. It'd be worth trying if I could get my hands on some liquid nitrogen!

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