# Can I use electrolytic caps in a RCD snubber circuit

I

#### Ignoramus15297

Jan 1, 1970
0
This is in regards to my IGBT based TIG welder DC -> AC inverter
project for a 200A welding machine.

Subject says it all. My new calculations suggest that I can
have a snubber circuit with 8,000 uF of capacitance rated for
200V. That would limit voltage in my system to under 200V.

Based on the following assumption:

Reactor inductance: 1.85 mH
Highest continuous current 350 A
Continuous Voltage 30V

(note that open circuit voltage is 85 V, but the current at that
voltage is 0).

I already have 200V, 10,000 uF capacitors, in fact more than one. They
are electrolytic. Also, I got myself some power diodes for the D part
of RCD. I will parallel them.

i

R

#### Rich Grise

Jan 1, 1970
0
This is in regards to my IGBT based TIG welder DC -> AC inverter
project for a 200A welding machine.

Subject says it all. My new calculations suggest that I can
have a snubber circuit with 8,000 uF of capacitance rated for
200V. That would limit voltage in my system to under 200V.

Based on the following assumption:

Reactor inductance: 1.85 mH
Highest continuous current 350 A
Continuous Voltage 30V

(note that open circuit voltage is 85 V, but the current at that
voltage is 0).

I already have 200V, 10,000 uF capacitors, in fact more than one. They
are electrolytic. Also, I got myself some power diodes for the D part
of RCD. I will parallel them.

Jeez, dude! Read a book or something!

No, you can not use an electrolytic cap for a snubber.

Analyze the circuit, and learn why.

Good Luck! (You're going to need a lot of it, at this rate.)
Rich

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