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Portable, Modular Capacitor Pulse Bank

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Hon1nbo

Sat May 02 2009, 10:14PM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: Pacific Northwest USA
Posts: 1042

So I have finally embarked to combine numerous interests: High Voltage, Capacitor Pulse Banks, Modularity, Pelican Cases, and Portability... Along with: recycled parts, (semi)-professional looks, and durability
My pulse bank project, is to be one of my rather larger projects, on which I plan to spend lots of time on, though it will be spread out due to exams, and will likely be my favorite undertaking, while hopefully being as green as possible (recycled parts, modular parts, lead-free, etc).

Current Power Status (as of 7/25/09): 4.2 kJ - more caps are gonna take time, seller only sells one at a time

Caps: currently 6x caps rated 5600uF @ 500V

General Physical Description:

the Pulse Bank will be designed such that it can fit into two, multi-purpose Pelican Brand Cases. One case will hold the Power Supply (which will also be multi-purpose as well as charge the caps), and the other will hold the Caps, Triggered Spark Gap, and the remote triggering controller... The design allows the parts to be easily removed from the Pelican Cases, so they can be used for other purposes...
the interconnection between the two cases is so far using a few main connections: a 3 pin XLR connector will be for monitoring the charge status to a panel on the charge controller; a terminal Block connects the Charging source to the caps; and a standardized 12V power connector connects 12VDC for various uses in the bank Assembly (such as the Spark Gap Trigger)...
The Triggered Spark gap consists of its own box allowing me to use it for other purposes and for easier maintenance... the same box will also hold the Diodes that protect the capacitors, the Resistors for the meters on the Charging Panel, and the general connectors for the cables between the two cases...

Electrical Design:
for the Charging Circuit, when using relatively low energies, I am going to use Uzzors Boost Converter Circuit; as for the higher energies, assuming that Uzzors circuit is not enough, I plan to use a transformer

I will rely now, primarily, on a mains fed transformer adjusted via a variac and switched with the shown circuitry - I may still build a boost converter for low energy purposes, but I will not use it for testing as it will no longer be a primary source of Capacitor Charging

The power input to the Charging Panel will allow for a mains connection, or for a 12V Battery...
the triggered spark gap will use a purpose made pulse transformer (I have officially decided to NOT to use a solenoid due to the likelihood of spot welding the electrodes)

Charging Panel:
The panel has (currently) a safety interlock key, a covered toggle switch, a charging momentary push button, and power source select switch, and a switch to enable to meters, a big, red Mushroom Button that, when normally closed, selects to charge the bank and when pressed will fire the bank
the panel will have charge status meters, a knob for varying the charge, and adjustments for the carious inner-workings of the charging circuits

Recycled Parts:
Bolts: I have used the same set of 1/4-20 Nuts and Bolts for several years, from one project to the next - something I think few can be proud of
PVC: I use lots of PVC, but I always recycle it when it is not from something like a cannon
Switches: the two covered switches, and the tubular key interlock switch have been in my work for years, with two of them having been in my very first Rocket controller... from 5th grade
Pelican Cases: I like to make these multi-use... and they make great enclosures!
Standard ABS Enclosures: the kind you get at radioshack or Fry's, has lots of holes, but most of them I make work out very nicely... even looks! - used same case for years, holds now the triggered spark gap assembly
Spark Gap Electrodes: I have used these since my first Tesla Coil
Meters: recycled from a Ham-Fest
Aluminum Tread-Plate: when my camera ballistics case went down the tubes... I actually though of using it for this exact purpose... and I am.
Cable Holders: I have used these for CNC machines... which I am upgrading, so these go here

not the most extraordinary set of re-used parts... but the list keeps growing, and count the money saved ^_^

Work Checklist:

assemble Triggered Spark Gap Assembly: Done
cut and install Capacitor Rails: [b]Done[/b] -UPDATE: Copper Rails have mostly been cut and installed, but there are two left for the newer caps
Mount Capacitors and Triggered Gap to base: Done
populate Trigger Remote: Done
Wire Trigger Remote: waiting until other circuits are installed due to possible wiring modifications
populate Charging panel: Work in Progress - only thing left are the meters and transformers
Wire charging panel: WIP
install charging Transformer: need to buy/harvest
assemble the Uzzors Boost Converter: POSTPONED
wire basic controls in Charging Panel: DONE
install Diodes in Cap Bank assembly:
perform basic function test without caps:
test low power pulse through triggered spark gap:
build higher energy charger and install:
install meters and associated circuits:
test extraneous functions:
test High Energy charge!:

UPDATE (5/31/09): I laid out the final configuration for the Triggered Spark Gap, then assembled it today, I used an old radioshack project box from an old project as the Triggering enclosure, and the enclosure for one of the electrode's connection to the Bank's load (note that the black box is bolted to the Plexi, so it and the Caps remain in the same relative locations to each other, as otherwise would prove problematic for setup)
I also got the hardware to mount the Capacitors to a piece of Plexiglass I had from an old Spark Gap Tesla Coil

except for the bolts used on the caps, and the Caps themselves - the entire cap/spark gap assembly is recycled from old projects

UPDATE (6/24/09): Posted a Schematic of the Basic Primary Circuits, and I decided to make the Charging Panel also the Firing Panel, but I am keeping the remote as a sub-assembly that can bypass the firing interlocks on the main panel, with its own interlocks, in case I REALLY want to be away from the panel when firing. - the new Primary firing button is also the charging switch... a Large Red, Twist-Release Mushroom Button designed as an Emergency Stop. It has Normally Open (the firing circuit) and a Normally Closed (charging circuit) state, which makes accidentally firing while the charger is on impossible, which is good because that would cause the Triggered Gap to, potentially, never close.

I also managed to get a hold on a true KiloVolt Meter at a Ham-Com! - it is an analog meter, measuring up to 15kV, and I only paid $2

UPDATE (6/29/09): After asking for opinions on my Schematic, it was noted that there were a few oddities that I have since fixed (and will upload once the computer copy has been updated): first the relay controlling the Variac was eliminated, since there is already control between the variac and the Charging Transformer I realized I did not need it, and it was going to likely cause issues since both relays were one the same circuit shorting to ground. I also replaced D1 with a Bridge Rectifier, and am placing an HV Capacitor and a Resistor on the Rectified output of the Charging Transformer. Also I placed a 12VDC Bus to an XLR Jack, along with the shown HV Trigger leads, to the Trigger so that the Bypass Triggering Remote can be used, as I already built it

Also, I have attached a few updated photos...

UPDATE (7/25/09) - I have bought, cut, and installed most of the copper Railing currently required, and the Aluminum Rails will be recycled for other uses. Also I have received two more caps, bringing the bank energy storage to 4.2kJ. Also I have decided that a Boost converter will not be my primary charging source, the transformer will be and the boost converter will be reserved for special use

other than that, things have been slow on the project due to Surgery - should be speeding up soon

UPDATE (10/25/09) - I finally rebuilt the firing panel to much simpler and more compact - the original panel made no room in the Pelican Case to allow storage of cables and the like, and it wasn't as modular as I had planned to noticeable problems in design. - the new unit is mostly built, and I have made a few significant changes in design. First, this is for the controls only now, meaning that the transformer for charging as well as the meters are not included because those are project specific items, so they will be built to be with the bank itself or in a small in-between box. The panel is interconnected with solderless tabs, allowing modifications of the switch and safety interlock arrangement for a specific task. I will keep the XLR type connections available, but there are also screw terminals so that I can use this with other things that XLR connectors would be a waste on, like rocketry controllers.

pictures soon

------------------photos-------

the Big, Red, Mushroom Button (NO and NC Contacts, twist to release):

a photo of the KiloVolt Meter I will be using to Monitor Bank Voltage (once the bank size increases as planned I will really need it):

the HV Transformer from a Neon Clock Tube I am using for the Trigger:

here are some Pics... some show an outdated component, but give the main idea and assembly

shot of the actual Cap. Bank, it's remote control, the case, and the spark gap - most of the major hardware assembled

a shot of the caps and the Triggered Spark Gap Assembly outside of the case

A closeup of the Triggered Gap Electrodes

a photo of the outside of the Capacitor Bank (a standard Pelican 1600 Case)

a closeup of the remote detonator (will replace with a full photo soon, I keep forgeting

some various meters I am choosing from for the main Control Panel

a full view of the Control Panel as it stands

1246329644 902 FT1630 Charging Panel Whole

some closeups of various parts of the control panel

a side view of the control panel, showing how I have designed it to not interfere with the operation of the case and that it will be removable with relative ease so that the case can be used for other purposes...

OLD:

Killa-X

Sun May 03 2009, 12:08AM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
Location:
Posts: 1039

Looks very nice! Good use of the case there, I hope it all works well for you. Looks very good so far :)

3l3ctrici7y

Sun May 03 2009, 05:13AM

Registered Member #1806 Joined: Sun Nov 09 2008, 04:58AM
Location: USA
Posts: 136

modularity

Hon1nbo

Fri May 08 2009, 10:02PM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: Pacific Northwest USA
Posts: 1042

another buyer is having a go at my Capacitor supplier, who only sells one at a time and he won't tell me how many he has left... I may have to start looking for another Capacitor Value Combination, as these capacitors normally are expensive

Hon1nbo

Sat May 30 2009, 01:30AM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: Pacific Northwest USA
Posts: 1042

UPDATE: summer is here, so I can start getting serious with this things...
first, I have installed Aluminum Capacitor Rails - I plan to replace these with copper, but they are good enough to test with and maybe even for full power, but we will see.
Second, I conceived a much simpler, more elegant Triggered Spark Gap assembly, which works with the cpacitor design - in the photos, the PVC end cap marks the location of the third electrode mount (note: it is not going to be mounted that far out of the way, but that is where the base connection will be)
the spark gap assembly and the Caps will be mounted to a thick sheet of Plexi I have, but I have to cut it first

this way, everything will be stable and not shift around in a way that might disrupt things (like the foam when used by itself might have caused)

PS: this is not the full size of the Capacitor Bank - it is designed to be expandable, and it will be expanded as soon as my supplier of the Caps puts more up for sale...

Hon1nbo

Mon Jun 01 2009, 12:12AM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: Pacific Northwest USA
Posts: 1042

Main Post Updated...

Hon1nbo

Tue Jun 23 2009, 10:41PM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: Pacific Northwest USA
Posts: 1042

main post updated

Hon1nbo

Tue Jun 30 2009, 02:49AM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: Pacific Northwest USA
Posts: 1042

main post updated with more Pics, and a description of Modifications to the Primary Circuit Schematic

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob