cheap way to charge a cap bank

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thingmaker3

Joined May 16, 2005
5,083
Talk to some of the electrical contractors in your area. We occasionally replace building systems (fire alarm, environmental controls, etc.) and toss the old ones in the dumpster (unless someone like me intercepts them). No guarantee, of course, but you might get a coulple kW worth of transformer cores which you could re-wind. You'll want a core (or group of cores) to handle 1.45kW or so.
 

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Joeshmoe

Joined Jan 12, 2007
66
If you have 110V circuits, then simple doubler will give cca 310V, which should be more than enough for a start. Be aware that the doubler needs non-polarised caps, the best would be motor starter caps.

With two 10uF caps in the doubler the 2200uF cap is charged to maximal voltage in about 5 seconds.

first off the caps i have are polarized... also what function do the 10uF caps serve?
 

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Joeshmoe

Joined Jan 12, 2007
66
since my caps are polarized what can i use to charge my caps? iv tried googling things like boost converter and doublers but i cant seem to find one that will work for me
 

thingmaker3

Joined May 16, 2005
5,083
Special thanks to member "HVFan" for their one and only post - sharing the following link:

http://www.blazelabs.com/cw-brm-java.asp

Note that you'll need to get your frequency up in the tens of MHz range before the C-W capacitors get affordable. (Those are not the same as the caps you are trying to charge.) Example: For a 4.5Amp o/p @ 400Vdc, using a 50MHz crystal ressonator ($1.00 from a surplus house) to drive a twenty-five cent MOSFET off a 12Vdc power supply (used car battery charger) you'll need nine dollar's worth of $0.25 2uF caps and an equal number of 4-for-a-quarter diodes. (Prices again assume surplus house). You'll have a little over 8V ripple.
 

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Joeshmoe

Joined Jan 12, 2007
66
thank you for the site but i still am not sure how to make the charger i will read the site more to see if i can figure it out but do you know of any sites that have specific scematics
 

thingmaker3

Joined May 16, 2005
5,083
At the bottom of the web-page are links to information on C-W multipliers and ressonant multipliers. Included on the additional pages are links to PDF files with math for optimization.
 

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Joeshmoe

Joined Jan 12, 2007
66
i must be missing it... could i get a direct link to somewhere that has a schematic for a charger that can charge my cap banks in a shot time
 

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Joeshmoe

Joined Jan 12, 2007
66
i just spoke to a friend who said he has a power supply that can give 350v and is rated for up to 10 amps... do i need to put resistors in my circuit or would the power supply limit its self (i dont want to blow out his power supply)
 

thingmaker3

Joined May 16, 2005
5,083
Depends on whether the supply is capable of limiting it's own o/p current. I'd put a 36 ohm resistor in series, just to be on the safe side.

Be prepared to blow a breaker. 3500W / 120Vac = nearly thirty amps.
 

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Joeshmoe

Joined Jan 12, 2007
66
i have a 120v in 25.2 v out 2 amp power transformer.... can i run in in reverse and and use it as my charger? i have diodes and a full wave bridge rectifirer and i can use them to to change ac to dc right? also should i put resisters in it to limit the current so the transformer wont blow?
 

thingmaker3

Joined May 16, 2005
5,083
You can do the math as easily as I, Joe. If one winding can handle 25.2*2 Watts, how many amps is the other winding likely to have been designed to handle?
 

andy73

Joined Sep 26, 2007
10
hi, sorry if this has been posted before (cant be bothered to read the whole post) but have you seen this booster?

oh and if you put k-joules through a coil i hope it's made of VERY think wire or you will vaporize it - done it; fun but not effective. + you will need some serious diode protection from the amps flying back from your coil "inductor" there's enough to kill your cap bank......BANG!!:D

all sounds like a big explostion to me, but hay good luck:D

you could use 5 charges charging 5 capbanks then dump the lot into one coil??? just an idea - 5 times the voltage + lower pulse time + lots of joules and one big M%$£%er F*&$%^ing bang!!!:D

cheers
 

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