High Voltage High Frequency Circuit for welder unit question

Thread Starter

psoke0

Joined Mar 31, 2017
187
hello guys . i want to add high frequency high voltage Arc starter feature to the cheap welder i have that i dont havem money to buy one with that feature.
my welder is DC inverter welder so the output curcuit in the welder as far as i can see is look like this
1.jpeg


and i write some curcuit that i dont know if it will work or not. here it is.

333.jpeg
now will the 300 V breakdown rated diode blow up if put a sparkgap in there ? i still want high voltage between clamps . so i put a mosfet in there too im thinking turn the welder power off while generating arc and turn the welder power on in the same time turn off the generator. but my mosfet is not high votlage rated either. so i dont know what to expect from this can spark gaps work for not break the diode and mosfet ? can you guys help me with this
 

Papabravo

Joined Feb 24, 2006
18,408
I think you will waste more time and money trying to find a solution that is safe and reliable. Just save your nickels and buy what you need when you can afford it. A mistake with this stuff can be fatal. Are you willing to take the risk?

You mentioned "high frequency". Are you aware that RF burns from a high-power source are some of the most painful and slowest healing burns that you can inflict on yourself?
 

Thread Starter

psoke0

Joined Mar 31, 2017
187
I think you will waste more time and money trying to find a solution that is safe and reliable. Just save your nickels and buy what you need when you can afford it. A mistake with this stuff can be fatal. Are you willing to take the risk?

You mentioned "high frequency". Are you aware that RF burns from a high-power source are some of the most painful and slowest healing burns that you can inflict on yourself?
the thing is i will not able to afford it at all. the prices in my country is nonsense.
i have the time . and components will be cheaper then buying one
 

Papabravo

Joined Feb 24, 2006
18,408
the thing is i will not able to afford it at all. the prices in my country is nonsense.
i have the time . and components will be cheaper then buying one
If you cannot take and use good advice, then at least be as careful as possible. We have more than enough members who have passed away, but AFAIK there have been no Darwin Award Winners.
 

Thread Starter

psoke0

Joined Mar 31, 2017
187
If you cannot take and use good advice, then at least be as careful as possible. We have more than enough members who have passed away, but AFAIK there have been no Darwin Award Winners.
thank you i know there is risk involved but i know how to protect my self in these stuations i allways get closer to the high voltage with respect. i know what it can do. im wearing protective gear. simple example i wear latex glove outside the very thick welding glove.
 

shortbus

Joined Sep 30, 2009
9,372
Many have tried to do what you want to do. Most have failed at getting it to work. There are two big problems doing this DIY, the first is isolating the inverter power from the high voltage. The second and seems to be the hardest one is getting the HV to combine with the welding voltage on the electrode wire.

You didn't say why your wanting this, but you must be aware that the HV HF start is only used in TIG welding, don't you? And from what you've said so far I'm assuming that isn't the type of welder you have right now. In stuff like this Google is your friend, if you know enough to try this you should also be able to figure out the "wheat from the chaff" in what is available in those websites.
 

Papabravo

Joined Feb 24, 2006
18,408
Many have tried to do what you want to do. Most have failed at getting it to work. There are two big problems doing this DIY, the first is isolating the inverter power from the high voltage. The second and seems to be the hardest one is getting the HV to combine with the welding voltage on the electrode wire.

You didn't say why you're wanting this, but you must be aware that the HV HF start is only used in TIG welding, don't you? And from what you've said so far, I'm assuming that isn't the type of welder you have right now. In stuff like this Google is your friend, if you know enough to try this you should also be able to figure out the "wheat from the chaff" in what is available in those websites.
That would be another vote for buy what you need. If the TS has the time and the money to waste on this quest, he should go ahead and prove it to himself.
 

michael8

Joined Jan 11, 2015
287
The output circuit in your welder may look like that but that's not the "theory" model of the welder.

OK, what does that previous sentence mean?

Circuit wise, a normal DC welder needs an inductor in series with the output to stablize the arc.

A "cheap" transformer can have leakage inductance (inductance not coupled to the other windings) which can be used as the stabilizing inductance.

To keep the HF (high frequency) out of the DC part you also need an inductance.

The above is a hint, don't have time right now for more.

Go look at schematics of welders..
 

Papabravo

Joined Feb 24, 2006
18,408
The output circuit in your welder may look like that but that's not the "theory" model of the welder.

OK, what does that previous sentence mean?

Circuit wise, a normal DC welder needs an inductor in series with the output to stablize the arc.

A "cheap" transformer can have leakage inductance (inductance not coupled to the other windings) which can be used as the stabilizing inductance.

To keep the HF (high frequency) out of the DC part you also need an inductance.

The above is a hint, don't have time right now for more.

Go look at schematics of welders..
Another vote for the TS having a whole lotta work to do before he can achieve his objective.
 

Papabravo

Joined Feb 24, 2006
18,408
you guys did very good job taking 5 years of electronics passion from my soul. thank you
Really? That's all it took. A great deal has changed in the last 50 years, and things that were possible and necessary then, no longer are. Assembled electronics then were relatively expensive, while time and raw materials were relatively cheap. Today it is the other way around. Finished goods are so cheap, that it is no longer worthwhile to design and build things for economic reasons. If it were otherwise, then Heathkits would still exist.
 

shortbus

Joined Sep 30, 2009
9,372
you guys did very good job taking 5 years of electronics passion from my soul. thank you
You say you can't afford to buy what you need, but you can afford to ruin what you have? You still didn't answer why you think you need this HVHF start. I've welded most of my whole life and Tig is the only electric welding type that uses it, and I even have a very old Tig that was scratch start. Do I like my new HVHF start welder better? Yes I do, but I used the scratch start for many years, the new one cost about 1/2 of the old one that I got 25 years ago.
 

Thread Starter

psoke0

Joined Mar 31, 2017
187
Really? That's all it took. A great deal has changed in the last 50 years, and things that were possible and necessary then, no longer are. Assembled electronics then were relatively expensive, while time and raw materials were relatively cheap. Today it is the other way around. Finished goods are so cheap, that it is no longer worthwhile to design and build things for economic reasons. If it were otherwise, then Heathkits would still exist.
okay you say its cheaper to buy finished one. here where i live the tig machine eith that feature never mind that feature even without that feature is so highly priced i will have to save money for 3 to 4 years to buy one. if the economics here doesnt get worse in 3 years of course. which it is going to . but the electronic components doesnt cost much that is why.
 

Thread Starter

psoke0

Joined Mar 31, 2017
187
You say you can't afford to buy what you need, but you can afford to ruin what you have? You still didn't answer why you think you need this HVHF start. I've welded most of my whole life and Tig is the only electric welding type that uses it, and I even have a very old Tig that was scratch start. Do I like my new HVHF start welder better? Yes I do, but I used the scratch start for many years, the new one cost about 1/2 of the old one that I got 25 years ago.
same thing. finished products are too expensive here. while components isnt. while i can afford components i cannot afford finished product that will take me alot of years of savings that i could possibly not buy it at the end anyway.
the reason i want that feature is i want to tack weld very small steel parts and stick is just allways sticks to the part and ruins it. i added a feature to the welder when i push the button the welder is active when im welding i can let go the button and welding stops. i did that because i will add another feature that will pulse weld . i will even add hot start too. those functions are easy for me. but i need that HF ARC start. it will make the job so easy and not ruin the parts
 

Thread Starter

psoke0

Joined Mar 31, 2017
187
well the stick sticks to the part just grind t right ? what is the big deal ? well i live in apartment and its like a joke. when we even walking they are complaining about it. do you think i could possibly use my grinder for cleaning . i tried file the parts which is making me so tired i just let it go
 

Thread Starter

psoke0

Joined Mar 31, 2017
187
guys all i needed was a bit of help . u guys dont have to even reply to anything but you did so why not just help a bit
 

Papabravo

Joined Feb 24, 2006
18,408
guys all i needed was a bit of help . u guys dont have to even reply to anything but you did so why not just help a bit
When you ask for help and advice you have to take what comes in. If the advice is not useful or not relevant you are of course free to ignore it. You don't get to whine about additional circumstances in the hope that the advice will change. We also don't have any idea what parts are or are not available in your location. You could spend your time becoming familiar with other units in the hope that you might learn enough to help yourself.
 

Thread Starter

psoke0

Joined Mar 31, 2017
187
When you ask for help and advice you have to take what comes in. If the advice is not useful or not relevant you are of course free to ignore it. You don't get to whine about additional circumstances in the hope that the advice will change. We also don't have any idea what parts are or are not available in your location. You could spend your time becoming familiar with other units in the hope that you might learn enough to help yourself.
i guess thats true. thank you guys anyway
 

shortbus

Joined Sep 30, 2009
9,372
guys all i needed was a bit of help . u guys dont have to even reply to anything but you did so why not just help a bit
Like our help or not it is what we've spent a lifetime finding out. Personally I'm 74 years old and have been doing this stuff since I was around 14 years old. What your wanting won't make stick welding any better or easier. For body work (which I've done a lot of) a oxy/actet welder is much better than stick or even Mig. While the HAZ is a little bigger the weld is easier to work down, not as hard.
 

Reloadron

Joined Jan 15, 2015
6,584
I am not a welding type and if you saw some of my weldments it would be apparent. I did have the pleasure for about 25 years of working with some of the best nuclear class welders around. Welding and really great welding is an art form. Nobody picks up a stick and makes a perfect beautiful weldment the first time around. It can take years of practice to start making good welds. That is the nature of the beast. It's a skillset that is developed and many start by welding scrap pieces together. Before we got really nice new stuff our guys were turning out really work on 1960s vintage machines They constantly developed their skills and that takes patience and practice.

Shortbus is likely the mostcompetent guy here to discuss welding so really give him a shot. He knows his stuff. He is one guy you want to listen to.

Good Luck
Ron
 
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