A few Design Changes

A project log for Simple Arc Welder & Optically Controlled Plotter

A simple arc welding circuit with high voltage arc starter and an optically controlled plotter.

dominik-meffertDominik Meffert 09/24/2020 at 13:180 Comments

In the last few days I tried to improve the circuit to get it ready for long operation times.

Things that I changed are:

- Replaced the transformer to get 60VAC 500VA, rectified around 86VDC open circuit and around 78VDC with the load.

- Removed the watercooler and added 12pieces 4 ohm 100W resistors to get 12ohm resistance.

- Added a line filter.

- Placed the HV supply on a pcb.

- Replaced the tesla circuit's ceramic capacitor with WIMA FKP1 capacitors.

- Added a capacitor across the coupling coil for filtering.

- Replaced the lightbulp with 4pieces 100ohm 100W capacitors to get 100ohm of resistance to discharge the welding capacitor and prevent random firing of the arc, because of the HF arc charging the rectifier capacitor. (Maybe at some point I will find a better solution, but for now it's ok.)

- Got a SSR to work by adding a snubber circuit (1nF 20kV capacitor + 20ohm resistor) to its output and zener diods to its input + switching it with 12V.

The next thing will be changing the optical trigger so that the HF arc and welding arc can be controlled separately.