Re: Capacitor charging
- One more question, folks. I've been looking into the HV rectifiers
and the best I've found so far is 80kv. Is it possible to connect
several in an arrangement that will give the desired result?
--- In VanDeGraaffGenerator@yahoogroups.com, "xraygunner"
> I guess I should have clarified that, yes I am using a voltage
> multiplier. I am assuming that it has a standard recovery time.
> I'll look into that. What I am mainly concerned with is making
> that goes into the capacitor I am charging, stays there untilallready
> purposefully discharging. Secondly I want to make sure that the
> discharge doesn't damage anything either. I am planning on a spark
> gap discharge if this helps.
> Thanks again for all the input so far. There is a lot of good help
> and advice out of this group.
> --- In VanDeGraaffGenerator@yahoogroups.com, Dave Jenkins
> <davejenkins70@> wrote:
> > If you are using a voltage multiplier/adder the output is
> DC at the output. 100kV you must be talking about a Cockroft Waltonneed
> style adder. If you're charging a cap after the adder you might
> a high meg resistor string to prevent damage to the addersrectifiers.
> > Sourcing and purchasing "new" HV diodes is a pain.. There isn't
> much demand for them and new HV rectifier stacks cost too
> much. You're better off buying them surplus. Go to ebay and search
> for rectifier diode or High voltage diode. You will find some there
> at a fraction of the original cost.
> > You didn't state the operating frequency of your multiplier...
> Rectifiers come in two flavors, standard and fast recovery.
> is typically 50 to 60 Hz (or a little more) and fast recovery isfor
> high frequency rectification.the
> > A source for 100-150kV rectifier stacks is from X-Ray machines.
> They are sometimes sold on ebay also. These stacks are strings of
> diodes placed in series and run at 50 to 60Hz.
> > You can build your own rectifier stack. Say you want to rectify
> 100kV. Buy 300 of the very common 1N4007 1 Amp/1000 Volt diodes
> and wire them in series in a zig zag layout. This will give you a
> 300kV rectifier. Typically you need to run stacks like this at 1/3
> their rated voltage and it's preferable all the diodes come from
> same manufacturing batch so the characteristics of each diode aresuch,
> close. Also single diodes/rectifiers rated for a certain voltage
> should usually be run at 2/3 their ratings.
> > --- On Mon, 8/25/08, xraygunner <xraygunner@> wrote:
> > From: xraygunner <xraygunner@>
> > Subject: [VanDeGraaffGenerator] Capacitor charging
> > To: VanDeGraaffGenerator@yahoogroups.com
> > Date: Monday, August 25, 2008, 5:27 PM
> > I know this is geared more toward VanDeGraaff generators and
> > but I was hoping I might get some insight on charging a capacitor.a
> > I started out wanting to build a vandegraaff, but soon found that
> > voltage multiplier would suit my needs better. I still follow thewould
> > group as there are things in here that apply to what I'm doing.
> > Right now I am in the process of building a capacitor that I
> > like to charge with approximately 85-100kv. The problem seems tobe
> > that I cannot find any diodes that would serve as the gatekeeperto
> > the business end of the capacitor that are in the kv range thatI'm
> > looking for. Are there any alternatives that I am overlooking?I
> > It seems that when I look into diodes with voltage ratings that
> > they begin to have "rectifier" in the name, and as far as I know
> > don't need that. I did however find this...
> > http://www.edidiode s.com/partnumber s.asp#hvassembli es
> > It's a part listed under the "High-Voltage Assemblies" series CYL.
> > Any ideas?
> > Thanks alot,
> > Troy