Measuring power output

[bc30se]

Hi Guys

I would just like to know, because my operating manual does not say a word.

How to measure power output of the mig welder. I would like to know what exact amperage my machine gives at each setting.

The power of my lincoln ranges from 25 to 250 amper and there are 20 settings all together

http://content.lincolnelectric.com/en/pdfs/products/literature/Powertec.pdf

 

[Wozzaaah]

If setting one is 25A and setting 20 is 250A and the steps are even then each increment would be approximately 11.25A .
Don't forget that wire diameter and feed speed both have a bearing on output current too.

 

[bc30se]

Do you think that you can take it for granted? I mean, is the increment anyhow consistent?

 

[Wozzaaah]

Sorry, just edited my post, wasn't expecting you to reply so quickly.You can assume the increments are even but to get the current as low as 25A you'd probably need to use 0.6mm wire and to get it as high as 250A you'd probably need 1.0 or 1.2mm so the voltage steps effectively become less even.

 

[snowcat]

Mesureing your OCV would be a far better option??

 

[bc30se]

OK, let's assume it is 0.8 wire all the time (by the way I succesfully welded 0.7 metal sheet with this without burning through), so... how does the power change for this wire?

 

[snowcat]

Its the voltage step that changes and the amps incresse as a result, only on this site will you ever hear of MIG plants messured in Amps, The proper way of taking a reading is to messure the voltage before you strike an arc (OCV) as the amps will change all the time.

 

[bc30se]

any ways of measuring voltage then?

 

[shenion]

Use a voltmeter

Best done with a light load, a 120/240V bulb will do. Measure across the torch and ground lead.

 

[bc30se]

Use a voltmeter

hmmmm, I was thinking about it, will give it a try today

 

[rtbcomp]

Amps depends on volts, wire thickness and speed. If you really want to measure amps whilst welding then a clamp type ammeter on the earth return is the best thing.

 

[bc30se]

So I measured voltage on each of the settings

1. 17.4v
2. 18.2
3. 19.1
4. 19.9
5. 20.7
6. 21.5
7. 22.3
8. 23.0
9. 23.7
10 24.4

11. 25.7
12. 27.5
13. 29.6
14. 31.7
15. 33.4
16. 35.4
17. 37.4
18. 39.3
19. 41.4
20. 43.5

Now.. how to put it into amps?

 

[Wozzaaah]

Read the whole thread and especially RTB's post again BC, you can't just say setting 10 @24.4V = x amps, it's not as simple as that I'm afraid.
What you can do now you know the voltage on each setting is to use the Miller calculator, input your parameters and it will give you an approximate amperage based on voltage, wire diameter and feed speed.

Edit: Unfortunately the calculator only takes into consideration 0.8mm wire and upwards so no good if using 0.6mm.

 

[rtbcomp]

Unfortunately the calculator only takes into consideration 0.8mm wire and upwards so no good if using 0.6mm.

Maybe the current is proportional to the crossectional area of the wire, in which case for 0.6mm wire multiply the 0.8 figure by (0.6^2)/(0.8^2) ???

 

[bc30se]

I am not expecting it to be very accurate, just more or less.. I wonder why lincoln did not give it in the damn manual...

EDIT:
Miller calculator is nice... but now I wonder, Why did I get 43v at the maximum setting while the manual says it is 26.6v max....

yes yes.. it's a little bit messy for me, I don't have electrician's mind..

 

[shenion]

I am not expecting it to be very accurate, just more or less.. I wonder why lincoln did not give it in the damn manual...

Because you cant say "setting x will be Y amps".

The voltage sets the range. The size of the wire and the wire feed speed set the current from that. You can vary the wire speed by about 15% and that will vary the current. Add to that the torch stickout length will vary the current. Also, different gas mixes will have different currents.

I find it frustrating that MIG specify 30-150 amps but never say what wire size sets that range.

Use the Miller calculator. It specifies the voltage and wire speed you would be using for the thickness you are welding. I guess next you will need to calibrate the feed speed dial

 

[bc30se]

Use the Miller calculator. It specifies the voltage and wire speed you would be using for the thickness you are welding. I guess next you will need to calibrate the feed speed dial

Yes of course but.... nothing like the voltages I got in the miller calculator, for example 9mm sheet should be welded win 220-250 amper which is 26 volts - actually the end setting of my mig according to the manufacturer.

But measuring it with the multimeter today I got over 40v at the maximum.... I am confused

 

[Wozzaaah]

I think it could be because you're measuring OC volts, Shenion mentioned in another thread about putting a domestic light bulb between the tip and the voltmeter contact to put a light load on the circuit, that should provide a more accurate reading.

 

[bc30se]

ohh fook.... forgot about it, kill me

so,

voltmeter minus to earth clamp
voltmeter plus to bulb ground
bulb plus to contact tip

then I measure?

 

[Wozzaaah]

Yes, that will do it.
Disclaimer: If it doesn't work or you hurt yourself, it was Shenion who suggested it, not me