Bert,
The caps see 2X Vpk input, except for the very first "AC" coupling cap.
Having just repaired several glassman HV supplies at work, this fact is
quite fresh in my mind ;-)
Steve
On Tue, Jan 5, 2010 at 12:26 PM, Bert Hickman <bert.hickman@xxxxxxxxxx>wrote:
Hi Thomas,
The voltage rating of each diode must be _at least_ 2 times the peak output
voltage of the HV supply. For the 10 kVrms SMPS supplies mentioned in the
original thread, if the supply outputs a (mostly) sinusoidal waveform, 2 x
Vpk would be about 3 x Vrms (rounding 28 kV upwards to 30 kV). However, I'd
suggest using a rectifier (diode chain) rated for a reverse voltage of at
least 3.5 - 4 x Vrms (or 35 - 40 kV) to provide healthy system margin and
robustness.
In a standard cascade C-W multiplier (using equal-value capacitors/stage),
each capacitor must be rated for _at least_ the peak voltage of the HV
supply (or 15 kV for a 10 kVrms sinusoidal source). I'd suggest using
capacitors rated for at least 2 x Vrms (20 kV) to provide good margins and
robustness. BTW, note that there are some other multiplier circuit variants
(such as Greinacher multipliers) that apply progressively higher voltages
across the DC stage caps.
Some additional sites you may find useful:
Theory and component rating:
http://www.eettaiwan.com/ARTICLES/2001JUN/2001JUN14_AMD_AN2009.PDF
http://hep.uchicago.edu/~rosner/p226/proj09/voltmult.pdf<http://hep.uchicago.edu/%7Erosner/p226/proj09/voltmult.pdf>
Java-based C-W calculator:
http://www.cosmicrays.org/muon-cockroft-walton-calculation.php
Bert
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jhowson4@xxxxxxxxxxx wrote:
Hey guys i have one of those solid state neon transformers as well,
and i too was looking for something useful to do with it. voltage
multiplier seems like a good idea. especially since i have a ton of
2kv .5A diodes and 2kv .01uf ceramic caps laying around. the
transformer is rated for 6kv 30ma
I know this is not a tesla coil question so respond to my e-mail at
jhowson4@xxxxxxxxxxx
How do you determine the voltage ratings for the diodes and the
capacitors needed in the multiplier circuit? I have looked on the
internet for an answer and have yet to find a clear one. Will the
stuff i have work.
thanks in advance , Jay Howson
Hi Thomas,
The high frequency (20+ kHz) output is ideal for driving a Cockroft-Walton
(C-W) Voltage Multiplier, since smaller HV capacitors
can be used in each stage. The following web page provides useful
C-W design info for both half and full wave C-W multipliers:
http://www.blazelabs.com/e-exp15.asp
Bert
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