Need Help in Choosing Right Capacitor & diode for 40KV DC from Neon Sign Transformer

rajheman, Fri Sept 18 2020, 01:00PM

i have variac transformer & Neon Sign Transformer with input voltage 230v Ac and output voltage of 2 x 7.5kv Ac = 15kv Ac.

i want to Build 40kv Dc high Voltage source from NST(neon sign transformer) which has two 7.5kv out put as shown in image.
with help of voltage multiplier i want this 15kv Ac to 40kv Dc High voltage source.

i need help to choose right 30kvdc capacitors And diodes for this multiplier.
Re: Need Help in Choosing Right Capacitor & diode for 40KV DC from Neon Sign Transformer
Flachzange, Wed Sept 23 2020, 05:31PM

Hi,
first of all, i can not see the image that you mentioned.
Then i would be helpful to know the application or the expected load of the DC supply.
Are there any restrictions concerning the ripple factor?

Since you have two outputs of your NST i would recommend a full wave voltage multiplier with 3 stages. That would lead to 45kV with no load. As diodes 1N4007 in series have prooven to be fine for my applications (only a few mA up to 2000 kV).

The capacitance needs to be rated for at least 15kV on each stage and the capacitance depends purely on the
other factors that i have mentioned at the beginning.