Inverter arc welder

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garidi

Joined: 30 Dec 2002
Posts: 14

13 Feb 2005 22:33 inverter circuit weld

Hello everybody, I plan to build an inverter arc welder.
It would be able to deliver an output voltage up to 100 volts and a current of about 200 Amps. Is it reasonably feasable? Smile

does anyone did it before? I would greately appreciate all suggestions.
I'll try to give a sketch of the shematic I have in mind next time.
Thanks.

IanP

Joined: 05 Oct 2004
Posts: 6492
Helped: 1542
Location: West Coast

14 Feb 2005 3:08 inverter welding circuit

100V output voltage sounds a little bit high.

I think the highest voltage in use is <40V ..
Currents of 100A, 200A +++ should not be a problem ..

marie65

Joined: 15 Jan 2002
Posts: 217
Helped: 10

14 Feb 2005 9:23 Inverter arc welder

Look at the producer's of power electronics sites. There are a few components special design for this task (soft FREDS if I'm not wrong) and you can find aplication notes regarding the subject.

Andrea

Joined: 30 Sep 2003
Posts: 76
Helped: 3

14 Feb 2005 9:35 Re: Inverter arc welder

I suppose that 100V is the open circuit voltage. Usually arc voltages are <40/50V (even 60V pk for pulse welding). Is this arc welder for MMA/TIG/MIG welding? If so you can look at specifications from arc welding machines manufacturers to see which are the usual voltage/current levels, and have an idea of how many inverter arc welders are available around the world, up to 30KW and possibly more!

platonas

Joined: 14 Aug 2004
Posts: 165
Helped: 5
Location: Universal Citizen

14 Feb 2005 11:00 Re: Inverter arc welder

I will comment on the output voltage only since I dont have anything else in mind.
You should certainly use voltages lower than 40V. This is due to total power needed by the utility supply. For 200A at 100V u need 20KW, this is too high for single phase supply, hence u must make it a 3-phase unit. Most arc welding equipment use as stated by other posters less than 40V.

garidi

Joined: 30 Dec 2002
Posts: 14

15 Feb 2005 19:02 Re: Inverter arc welder

thanks for all the fellows for your replys Smile

I think that the remark which concerns the output voltage (ie. of about 40v) is relevant, but for some special uses (aluminium welding) we need higher values.
Also, it is right that the output voltage has a falling characteristic.
The power consumption should be less than 5kw.
I believe i could give more explanations, but i still dont know how to attach images in this forum Smile

so forgive me again. I'll do my best in the future.

gogi

Joined: 27 Mar 2002
Posts: 14

16 Feb 2005 7:57 Re: Inverter arc welder

Relation between welding voltage and welding current

MIG/MAG U = ( 14 + 0.05 x I ) _____ 100A --> 19V
TIG/WIG U = ( 10 + 0.04 x I ) _____ 100A --> 14V
Menual metal arc welding U = ( 20 + 0.04 x I ) ____ 100A --> 24V

Higher open circuit voltage is better for start welding ( higher then 70V ).

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Andrea

Joined: 30 Sep 2003
Posts: 76
Helped: 3

16 Feb 2005 9:37 Re: Inverter arc welder

Are you going to develop it for hobby or at work? Remember that you have to comply to european standards (for european market / CE). The main one is EN60974-1 (where you can find V/I relationships) but others apply too.

Andrea

Joined: 30 Sep 2003
Posts: 76
Helped: 3

28 Feb 2005 10:40 Re: Inverter arc welder

To GOGI:

you posted very good material about welding technology....
do you have any other related documents by FRONIUS (or other manufacturers) to share??

Thanks