Re: [TCML] Tesla coil with 125kV, 600ma primary transformer.. is it worth doing it ?

["David Rieben" <drieben@xxxxxxxxxxx>]

Hi Simonas,

You will find that the challenges to using an x-ray transformer
(I'm assuming it was originally the HV generator of an x-ray
system, due to its ratings) are quite significant. Scot (aka bun-
nykiller) can tell you all about the corona issues with using
just ~30 kV primay voltage. These issues would certainly
be highly compounded by 4X that voltage!

Also, x-ray transformers are NOT rated for their nameplate
kVA rating at 100% duty cycle like pole pigs, PTs, or
plate transformers, so I seriously doubt that your x-ray
tranny can supply 75 kVA on a continuous basis without
eventually overheating. Remember, in their "working" en-
vironment, x-ray transformers are usually energized for
only fractions of a second, so a 100 % duty cycle rating
is not necessary. Besides that, I'm pretty sure that your
home's electrical service cannot provide 75 kVA on a
continuous basis either. ;^/

I have heard of someone using an x-ray transformer as
a Tesla power supply by keeping the spark gap narrow
enough as to prevent potentials from exceeding the typical
Tesla primary circuit voltages (~10 - 20 kVAC). "I" would
think that you'd be better off to just get a pole pig, as big
Tesla coil sparks LOVE lots of current and pole pigs are
seem quite happy to oblige. ;^) I don't think the x-ray
transformer could supply near the current that a pole pig can
if you were to keep the voltage clamped down to < 20 kV.

Having said all that, I still would not "turn down" a chance
to obtain an x-ray transformer. Although they are NOT very
suitable Tesla coil power supplies, they ARE suitable
for a stiff and powerful  >100 kVDC (AC, too, if you
get into the tank assembly and remove the diode sticks)
power supply. And yes, it you opt to remove the diode
sticks to make it AC, it will make for an oily mess! ;^0
Also remember, an x-ray transformer will require external
ballasting just like a pole pig, if you're intending to draw
sparks with it!

David Rieben



----- Original Message ----- 
From: <rasim@xxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Tuesday, October 20, 2009 7:23 AM
Subject: [TCML] Tesla coil with 125kV,600ma primary transformer.. is it 
worth doing it ?


> Hello,
>
> It is three phase unit, so I think DC ASRSG coil design should be used.
> I've got opportunity to acquire such transformer and have been wondering 
> about all the problems associated with having such a high voltage in the 
> primary circuit - requirements for capacitors, arcing issues (what should 
> the rotary size be for example to assure sufficient quenching), building 
> primary inductor (choke) for such voltage, etc.
> I've already have some 40kV rated capacitors and diodes, but still, having 
> built only 10kV, 10kva coil previously, this looks a bit challenging :)
>
> So I just wanted to hear some opinions about the subject and maybe 
> experiences with such high primary voltage.
>
>
> regards,
> Simonas
>
>
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxx
> http://www.pupman.com/mailman/listinfo/tesla 

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