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Re: Are these maxwell caps OK?



Original poster: "Jeremy Scott by way of Terry Fritz <twftesla-at-qwest-dot-net>" <supertux1-at-yahoo-dot-com>

Hi, 

I plan on using 3 of these to power my coil. :)

I've got a 15KV/60mA NST. 
At AC sine-wave peak, it'll kick out 21KV so, 
breifly, before reversing current. 

My series of 3 Maxwell's will have a 'package' rating
of 105KV (35kV * 3), so common sense would tell you
that I'm safe right? Not quite....

I examine the specs further, and their reversal rating
is only %15! That means my series is really only 'safe
rated' to 15.75kV when working with AC. Anything
beyond that is pushing it. And we do push.

Assuming I set a static spark gap for 21KV, these
capacitors won't be storing over-rated voltages
for relatively 'long' periods of time before
discharge. That's good, and well below the 50% "max
voltage reversal" spec. 

My guess is Maxwell is telling us:

"AC peak to peak voltage rating = 50%, True RMS = %15"


The same applies for the current specifications,
sure at 'peak' it's 20kA...but you can't setup
your coil to do this and run it all the time
at peak. It'll blow. It's RMS current is only 
20A.

So I figure, in tesla coil design, 3 of these 
in series can handle 15Kv -at- 20A of 60Hz AC until
the cows come home, and survive the occasional spikes
of 50Kv -at- 25kA. 

I don't plan on running my coil 'continuously', and
plus I'll have a saftey gap set for somewhere below
50Kv, but above 21KV. 

If you're planning on using ONE of these Maxwell's,
then be very careful, and do have safety gaps. Also,
don't buy em from alltronics. Check out Ebay first. 


--- Tesla list <tesla-at-pupman-dot-com> wrote:
> Original poster: "Gregory Peters by way of Terry
> Fritz <twftesla-at-qwest-dot-net>"
> <s371034-at-student.uq.edu.au>
> 
> Hello all,
> 
> I am interested in buying Dan's maxwell caps. The
> specs can be found 
> at:
> 
> http://www.alltronics-dot-com/download/20P005.pdf
> 
> I'm worried about the maximum voltage reversal of
> only 50%. Are these 
> caps OK for tesla coil use? Other than that, they
> look pretty good 
> with their 25kA max current rating.
> 
> 
> Cheers,
> 
> Greg.
> 
> 
>