strange Neon sign transformer

[neggyenergy]

Hi,

i need a single 3000 volts connection but my neon sign transformer has two 1500 volts connections, i am a newbie, so i am confused,
can i get two high voltage diodes and connect the two outputs to a single wire to get a single 3000 volts connection. i want the other end to be ground that is why i am not connecting the two outputs across.
can anyone help if the diode idea would work or not.

[CompuTutor]

I'm just throwing this out there,
but without that transformer in front of me...

It is highly likely (That for safety) those two outputs
swing plus and minus in relation to ground.

So the total voltage potential stays at earth ground.

Or another way to say it is grounded center tapped secondary.



That means you already have
3-KV BETEEN the two terminals.

But only 1.5-KV in relation to ground.

While one is -1.5-KV
the other is +1.5-KV.

and they of course swap @ 60-CPS
following the line input sine wave.

Thus causing the two outputs to maintain
a cancellation of dangerous voltage
in the operating enviroment.

As one is rising negative,
the other is rising positive
while following the sine
cancelling each other out
and achieving a common-mode
potential of zero volts nearby.

Test for equal resistance to the
transformer ground and/or case
from both out terminals.



Now here is the potential problem with this,
you indicated a reference to ground initially.

You were not specific about application,
but the implications are paramount to safety !

If you ground one of these output terminals,
your allowing the primary input exposure to
unsafe voltage potentials of 1.5-KV essentially .

Your also relying on the dielectric strength of
the windings insultation and transformer design
to sustain one half of that 3-KV output.

Not a good idea...



Can you share a little more about referencing ground
without giving away more than your comfortable with?

[Judges]

Your transformer (Jefferson?)(Franceformer?) is 7500 volts measured from one terminal
to case,,,from terminal to terminal the face plate voltage is 15000 volts.There are no 30KV NST's.You either have 30ma, 60ma, or the 'hard to find' 120ma.


You may find some help by Google 'Marx Generator' which is a diode cap step up chain.
Good luck,,please play safe..
Joe in Texas

[mscoffman]

If you have a 3KV Ct. center tapped transformer and want +3KVDC output,
see attached schematic. Full wave voltage doubler. You will probably
want high resistance bleed-off resistors in parallel with each diode because
there is no DC path through the transformer. You may want to test with 1VAC
on the primary giving 30vdc on the secondary before going to full power.
Caps should be like 6KWVDC.

:S:MarkSCoffman

[the_big_m_in_ok]

Hi,
i need a single 3000 volts connection but my neon sign transformer has two 1500 volts connections, i am a newbie, so i am confused,

Why not use a lower voltage transformer and add a Cockroft-Walton multiplier bridge to it?

http://en.wikipedia.org/wiki/Cockcroft%E2%80%93Walton_generator

--Lee