Power supply for welding machines 2

[AusLee]

Hi,

The data we have on a welding machine is as follows:

Lincoln Power Wave - 3 phase 230/400V 60% 44A 100% 33A

I'm assuming the 60% and 100% are the duty cycle.

Q1: is it normal that the current in 100% duty cycle be less than 60%?
Q2: what is the required rating of circuit breaker to properly supply this machine?
Q3: if we have a number of those, how do I calculate the power factor so I can propose a correction?
Q4: i looked up a datasheet online but found only the 60Hz model. Assuming that's the only model in existence, what will happen when plugged to 50Hz?

Your help is much appreciated.

 

[waross]

How about a model number??
I see about 14 Power Wave models. Many of them will automatically configure themselves for input voltage, Hz, and single or three phase. At least one is listed as high power factor.
Duty Cycle Example:
Machine capable of 100% duty cycle up to 180 Amps.
At 300 Amps the duty cycle must be limited to 40%.
I am not familiar with welders with output currents as low as 33 Amps and 44 Amps.
I am not familiar with the duty cycle being applied to the input current.
At full output, the supply must be capable of supplying full rated current, just not all the time. The duty cycle of the output has to do with internal heating of the machine.
A duty cycle current rating on the primary may be useful to estimate a diversity factor for a feeder feeding a number of welding machines.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Skogsgurra]

Yes, running 100% heats eveything more than running same equipment 60% duty. The ratio is approximately 1/sqrt(duty cycle). So, if you run 44 A at 60%, you can run appr. 44*sqrt(.6)=34 A at 100%. The reason why the 34 A have been reduced 1 A is that you always have "idle heat" that adds to the internal welding losses.

Units like these are often connected to 32 A outlets (Sweden/Europe) if they are used for repair purposes (low duty cycle) and 50 or 63 A if they are used 100%. Other countries have other systems and the rated current will differ.

Power factor correction may not be needed. The supplier's literature should give some hints.

Lincoln's units can usually be run off 50 or 60 Hz grids. If you know the exact type designation, there are manuals available on the net.




Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[Skogsgurra]

I got interrupted, Bill. So I didn't read your answer.
I think that the 33 and 44 A rating is input current.

And, yes, those units should be possible to run on 50 or 60 Hz.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[waross]

Hi Gunnar. Our codes do not allow protection based on the reduced service factor. The operator is not trusted to never go above the lower rating.
I think that AusLee is in Australia and I don't know the codes in force there.
Given that we cannot all see the same internet from different places in the world, I hope that this Lincoln Welder link works:

http://www.lincolnelectric.com/en-us/Equipment/Pages/product.aspx?product=K2823-3(LincolnElectric)

Excerpt:
Power Wave S350:
PowerConnect™ Technology (Patent-Pending) - Automatically adjusts to input power from 200-600V, 50 or 60 Hz, single phase or three phase.
Tribrid™ Power Module - Exceptional welding performance with high power factor and efficiency.
From specs:
Input Current
3PH/40% - 39/35/19/17/14A
1PH/40% - 60/61/NA/NA/NA A

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Skogsgurra]

I think that I was thinking spot welder instead of stick/TIG etcetera. For a stick welder, both 33 and 44 A mains current on 400 V is a bit high.

The protection is not the problem and the Eurpoean authorities do not trust welders either. It is about what outlet you can find to run the welder. A 16 A outlet is easy to find in EU, a 32 A can be found and an outlet that can deliver 44 A is more problematic. So, it is good information that the welder can be run from a 32 A outlet if you keep the duty cycle low.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[AusLee]

Hi thanks for the replies. Yes I'm in Australia

Can you please clarify your understanding if the output of 33A and 44A, is that at mains voltage?

If it is, then the cable and circuit breaker should not be a problem, we won't go cheap.

But i thought the output voltage is usually at lower voltage, and it is DC so that they get good welding, so inside the machine there would be a transformer and diodes, hence the high power factor.

 

[AusLee]

Pretend you did not read that
I got all the info needed. Thanks for your help!

 

[AusLee]

Hi

Sorry one more question please:

Is there any particular issue with providing a 30mA RCD/GFCI at the input supply to welding machines?

Thank you.