/diy/ - Do It Yourself

>>1682786
>other explanations of Q factor
>basically a mechanical version of an LCR oscillator, though in your case it's driven by a spark-gap circuit
Thanks, any tips on finding resources/explanations on these? The only thing I found on spark gap oscillators are the old spark gap telegraph transmitters.
>Really? 0.2mm each? That would correspond to a total breakdown voltage of about 1.2kV
Yes, 0.2mm each. Sorry for stupid question, but in practice, how does one actually measure HV capacitative circuit voltages? Alls I have is a 600V multimeter. Seems weird if this is all done theoretically.
The way it is set up now, none of the components listed in the diagram is getting above room temp with R5 set to the minimum resistance. Just based on experience with other stuff, it seems like R5 should be the changeable value that increases or decreases the temps and stress on the caps. Even with R5 set to minimum it seems like the caps hardly register a difference. Also, I kind of skipped the detail earlier where when R5 was turned up to max resistance or even 50% resistance, I'd have to scratch start the electrode and weld for at least a few seconds before it would HF start and jump a gap and then if I stopped and let it sit for a while, it would only start if I tapped the electrode against the workpiece with everything off and no current flowing before it would jump an air gap at the electrode, so it would be nice to be able to turn it up a little bit I think. Brb I will check the min and max resistance of R5 assuming that would be useful to your analysis.
Again pic required, R5 for your viewing pleasure.

>>1667457
>>1667437
>>1667484
Sorry, getting readings off of this thing is a PITA because all the terminals are covered with 1/4" of bat shit, but R5 is definitely a variable resistor controlling "HF intensity", With the dial set to zero and not accounting for any bat shit in the circuit, it reads like 6-7 ohms, and with the dial set to 100 (max HF), it reads 3 ohms? From the technical manual from the similar welder the resistor R5 is described as "Rheostat WW 150 w 5 ohm". The attached pic is the Rheostat/resistor in question.
>>1667457
>>1667484
>starting cap
The way it's supposed to work is that in DC mode, the HF is used just to initiate the arc, once arc voltage is sensed, it initiates the "HF timer" which would turn HF off in a matter of seconds after the arc is established, so yes, HF would just have to run for maybe 5-10 seconds at most and then be off for a minute or so until you start the next weld. In AC mode, I the selector switch would be in the "continuous" position because it's using HF to re-establish the arc every time the AC voltage changes polarity.
>shitty tesla coil
Yes, that's exactly how it works / looks like in operation. I don't know what implications the resistance discussed above has for the current running through these caps, but this type of transformer welder can do an HF arc like 3-4 feet long through the air, whereas the newer inverter ones can do maybe 2-3 inches at most presumably from running less current / smaller caps in the HF circuit?