Welding current characteristics

[dobre]

Hi all,
here is a bit of info to help understand welding currents.
1. Alternating Current
In alternating current the generated heat is balanced between the work and electrode as the electron flow continually and quickly reverses.

2. Direct Current
In direct current the heat generated can be change by altering the electrical value of the work and electrode changing the polarity.

3. Results of settings.
a. ELECTRODE POSITIVE
When using this setting 2/3rds of the heat is generated on the positve side of the circuit, therefore if a greater amount of the deposition is required, it is important that the parent metal should be connected to the negative side and the electrode to the positive side. This situation will result in a greater amount of heat being generated at the electrode which increases the burn of rate, this will give a wider flat bead with shallow penetration.

b. ELECTRODE NEGATIVE
When you use this setting 2/3rds of the heat is generated on the positve side of the circuit, therefore the greater amount of heat available can be concentrated on the parent metal to increase the depth of penetration by making the electrode negative and the parent metal positive.

This will give you a simple understanding of how polarity works and chosing the right the right electrodes that will suit your machine and job intended. Having said this most electrodes available today can be used in most polarity setups and this is a good thing especially for the hobby welder.

Dobre

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Dobre.

www.dobbieswelding.com.au
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[midseries]

Hi Dobre, This is my first post and im glad you guys are out there to help with our problems, i have a little cigweld 170 amp inverter arc welder,that has replaced my old ac clunker of many years, in regard to your post on current charcateristics, does that mean if i'm welding on 100 amps with electrode positive, and change to electrode negative do i have to back of my amps a little due to greater penetration, also will electrode neg let me sneek up to 4mm rods for some work due to the better penetration, i'm not a pro welder just a maintance and handyman welder, but i love welding, Thanks Mate Andy.........

[dobre]

Hi Andy,
you have asked a very good question and basically the answer is yes. Having said that the general h/man would not have to be too concerned with this issue due to the fact of what they are welding up. It is generally light gauge material from 1.6 - 4 or 5mm and for the intended project the penetration is not really a concern. Most welding rods these days can be operated in either ac or dc (- or + ) and there will be info on how to run these rods for the particular job. There are electrodes designed just for penetration and root runs and then capping runs are done with others.

It all comes down to the job that you are doing and with this in mind the choice of welding electrode that you will need. The other thing is some welding machines can only weld in ac format, some are dc only, some dc- and dc+ and some machines will run ac, dc- and dc+. The more welding options there are usually will follow with a higher price tag.

[midseries]

Thanks for the reply mate, andy