Hi,
I'm currently building a complete WIG/TIG welder... microcotroller PCB
is runing and will be programmed probably next year (takes some
time ;-)
Currently I'm working on the arc starter.
I found an television high voltage transformer which has its resonance
frequency at 310kHz.. .I don't know why, but thie high frequency
works.
I get 3..4 cm at 12V and 2A... really lucky about that.
But I still failed to make the couppling from HV-side to the LV
welding lines.
There are several pictures available in the web with eg 20:20 turns...
every link says ... its running perfectly.
Here how I tried...
make 20:20 turns air coil with a diameter of app. 15mm...
connect one HV wire directly,
the second with a 1cm gap (no cap!)
No I was assuming to get a nice HV on the secondary side, but I get
nothing!
What is missing?... and why??
Please be so kind and tell me you opinion
If you have good links/suggestion... please post it
You can also write to
If I get good suggestions, I will summarize everything here.

Thanks and have a nice day

Best Regards

powerfreak

wrote:
Hi,
I'm currently building a complete WIG/TIG welder... microcotroller PCB
is runing and will be programmed probably next year (takes some
time ;-)
Currently I'm working on the arc starter.
I found an television high voltage transformer which has its resonance
frequency at 310kHz.. .I don't know why, but thie high frequency
works.
I get 3..4 cm at 12V and 2A... really lucky about that.
But I still failed to make the couppling from HV-side to the LV
welding lines.
There are several pictures available in the web with eg 20:20 turns...
every link says ... its running perfectly.
Here how I tried...
make 20:20 turns air coil with a diameter of app. 15mm...
connect one HV wire directly,
the second with a 1cm gap (no cap!)
The typical TIG HV system has an old-style tesla coil circuit,
with a 10 - 20 turn secondary that the torch lead is connected
in series with. This produces a few hundred volts open-circuit
and adds it to the torch open-circuit voltage.

Jon

wrote in message
...
Hi,
I'm currently building a complete WIG/TIG welder... microcotroller PCB
is runing and will be programmed probably next year (takes some
time ;-)
Currently I'm working on the arc starter.
I found an television high voltage transformer which has its resonance
frequency at 310kHz.. .I don't know why, but thie high frequency
works.
I get 3..4 cm at 12V and 2A... really lucky about that.
But I still failed to make the couppling from HV-side to the LV
welding lines.
There are several pictures available in the web with eg 20:20 turns...
every link says ... its running perfectly.
Here how I tried...
make 20:20 turns air coil with a diameter of app. 15mm...
connect one HV wire directly,
the second with a 1cm gap (no cap!)
No I was assuming to get a nice HV on the secondary side, but I get
nothing!
What is missing?... and why??
Please be so kind and tell me you opinion
If you have good links/suggestion... please post it
You can also write to
If I get good suggestions, I will summarize everything here.

Thanks and have a nice day

Best Regards

powerfreak

Hi powerfreak

I have a Lincoln unit designed to make a stick welder to be used for TIG.
I can take its lid off and send you some pictures of their method of
coupling the HF to the welding cables.
Lincoln aparently connects a low inductance , low resistance coil in
series with the welding lead. That coil is the secondary of their HF
transformer.

Jerry KD6JDJ

wrote: (clip) I get nothing! What is missing?... and why??
(clip)
^^^^^^^^^^^^^^^^^^^
At the frequency you are running, you probably have too much inductance in
your little transformer. Couldn't you hook directly into your welding
cable, so the HV goes in parallel to your welding voltage? Its purpose is
just to ionize the air and get the arc started, and then you don't need it
any more.

On Feb 17, 3:51 pm, "Leo Lichtman"
wrote:
wrote: (clip) I get nothing! What is missing?... and why??

(clip)
^^^^^^^^^^^^^^^^^^^
At the frequency you are running, you probably have too much inductance in
your little transformer. Couldn't you hook directly into your welding
cable, so the HV goes in parallel to your welding voltage? Its purpose is
just to ionize the air and get the arc started, and then you don't need it
any more.


Points to ponder:

You finally got the 3000 to 10,000 Volts HF onto the welding cables to
initiate the arc.

How are you going to prevent this Voltage from destroying the DC
rectifier diodes and the insulation of the welding transformer??

What you need to consider is to place a 16 micro farad capacitor, AC
service type, as a shunt across the welding current terminals; in
effect this capacitor is in parallel with the bridge rectifier and
the welding transformer, providing a HF short circuit path.

Also place .1 micro farad caps in parallel with each individual
rectifier.

Don't ask how I know, but AC service capacitors, while expensive, are
cheaper than 250 Amps / 300 Volt rectifier diodes. :-)) My son
converted a Lincoln tombstone AC buzz box into a full blown AC/DC TIG
machine with foot pedal current control and HF arc starter. Nice
machine.

Wolfgang

On Sun, 17 Feb 2008 06:45:49 -0800 (PST), wrote:

Hi,
I'm currently building a complete WIG/TIG welder... microcotroller PCB
is runing and will be programmed probably next year (takes some
time ;-)
Currently I'm working on the arc starter.
I found an television high voltage transformer which has its resonance
frequency at 310kHz.. .I don't know why, but thie high frequency
works.
I get 3..4 cm at 12V and 2A... really lucky about that.
But I still failed to make the couppling from HV-side to the LV
welding lines.
There are several pictures available in the web with eg 20:20 turns...
every link says ... its running perfectly.
Here how I tried...
make 20:20 turns air coil with a diameter of app. 15mm...
connect one HV wire directly,
the second with a 1cm gap (no cap!)
No I was assuming to get a nice HV on the secondary side, but I get
nothing!
What is missing?... and why??
Please be so kind and tell me you opinion
If you have good links/suggestion... please post it
You can also write to
If I get good suggestions, I will summarize everything here.

Thanks and have a nice day

Best Regards

powerfreak

You're over an order of magnitude too low in frequency. 8 MHz is
more in the ballpark.

Jon Elson wrote:

The typical TIG HV system has an old-style tesla coil circuit, with a 10
- 20 turn secondary that the torch lead is connected in series with.
This produces a few hundred volts open-circuit and adds it to the torch
open-circuit voltage.

My Thermal Arc will jump a good inch and
a half, which would be about 6500 volts AC.

On 2008-02-19, Jim Stewart wrote:
Jon Elson wrote:

The typical TIG HV system has an old-style tesla coil circuit, with a 10
- 20 turn secondary that the torch lead is connected in series with.
This produces a few hundred volts open-circuit and adds it to the torch
open-circuit voltage.

My Thermal Arc will jump a good inch and
a half, which would be about 6500 volts AC.


I always turn my arc starting to a low setting, enough to jump 2 mm or
so. Much more comfortable.

i

Hi together,
thanks for the hints, I'll try and report again...
please do continue to post recomendations, links or pictures and feel
free to contact me directla
Thanks
powerfreak