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Re: Get it over with
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> From: Tesla List <tesla-at-poodle.pupman-dot-com>
> To: Tesla-list-subscribers-at-poodle.pupman-dot-com
> Subject: Re: Get it over with
> Date: Sunday, February 02, 1997 8:25 PM
>
> Subscriber: Kilroy-at-bscn-dot-com Sun Feb 2 17:29:42 1997
> Date: Sun, 02 Feb 1997 02:04:32 -0600
> From: Kerry Ludwig <Kilroy-at-bscn-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: Get it over with
>
>
> >>3. I would like to use my 12kv/63ma neon trans. and build a filtered
d.c.
> >>supply to run my coil off of. Can anyone tell me how to figure the
inductor
> >>(in series with trans) and cap (in parallel with trans) values for this
> >>circuit? (I hope to someday also build a larger scale coil of similar
> >>design, so the actual formula's would be useful.)
> >
> >
> >I assume you are talking about a DC supply, series filter choke to keep
RF
> >and kickback out of the DC supply. The general rule is to use the
largest
> >value inductor you can get your hands on which will take the voltage
stress.
> >Such items are military items only and found only surplus at hamfests. I
use
> >a .4 henry unit rated for 20 kv on my small DC system. R. Hull
>
> I am looking to build a circuit to filter out the 60Hz ripple of the
> rectified output from the trans. At least down to tolerable levels. Maybe
> less than 5%? I planned on using seperate filters for protection.
>
> Kerry "Kilroy" Ludwig
> Kilroy-at-BSCN-dot-com
Kilroy,
Why would you want to keep the 60Hz ripple low? Your firing rate is going
to be equal to or greater than 60 per second, isn't it? So what do you gain
by more filtering?
In a regular DC power supply the ripple is caused by the discharge of the
supply capacitor(s) during the time the charging current is below peak. In
a classic brute force power supply they do this by throwing more
capacitance in there. This requires that the transformer be able to charge
them all, and so it has to do even more work. The diodes now experience an
increase in current, too. Throw too much capacitance in there and the
transformer start up currents can become excessive and cause a fuse to
blow, or your diode decides to play dead. As applied to a Tesla coil, it is
not really a good idea to "filter" the DC, since it does not see a
resistive load, but one that changes drastically from a non-conducting
state to a conducting state. You may even have to add some resistance/coil
into the diode section so that upon firing you don't overload the diode.
This is the opposite of filtering!
Fr. Tom McGahee