How many kva needed on a portable gen to run a 170 amp welder properly?

[soundbeltfarm]

as title says, i have a 170 amp inverter stick and 180 mig and i want to be able to use them on the farm with a portable gen but i have been told different ratings i will need to run them. anyone here that actually knows what kva i will need?
Thanks

[avgas]

I get around 42kVA (no I am not joking)........but that sounds a bit high......mabey I am missing something about generators. But calc is (without power factor correction)
230 x 180 = 42KVA

Any chance you can turn down the load on the welders? How often do they need to go full load? Because the more you bring that current value down the smaller the gen...

[avgas]

Oh and I am assuming single phase here........

[avgas]

Did some quick research - typical 250A welder runs good at under 100A for short bursts (12" bead etc).

So that brings it down around 20-25KVA

[bogan]

both be single phase welders? if so I would assume not too much more than a single phase outlet can supply, what ratings were you given?

[soundbeltfarm]

i have been told from 4 kva to 7 kva and there is a lot of price difference in that range.
both single phase welders.
they have all said it is when you first create the arc that draws heaps of power.

[bogan]

i have been told from 4 kva to 7 kva and there is a lot of price difference in that range.
both single phase welders.
they have all said it is when you first create the arc that draws heaps of power.

Hard to say exactly, if you are unlikely to need max power welding I'd go for the low end, and be stoked if it works for full noise. As you say, the power is required for creating the arc, so be pretty hard to quantify it exactly.

[pete376403]

If you can run the welder out of a normal domestic socket, unless i'm missing something, this page http://www.dieselserviceandsupply.co...aspx#PowerCalc
gives a single phase, 230 volt, 16A with 0.8PF a kVa rating of 3.68. Are gensets rated differently?

[dhunt]

as title says, i have a 170 amp inverter stick and 180 mig and i want to be able to use them on the farm with a portable gen but i have been told different ratings i will need to run them. anyone here that actually knows what kva i will need?
Thanks

An arc welder generally run at about 20VDC so 170 x 20 = 3.4KW. The initial startup current maybe higher. A lot of the newer welders have a higher voltage start so they don't stick so easily so could use more power on startup.

Do the welders have any input rating stickers on them? Most products come out with a sticker. ie (230V 15A)

[pete376403]

Is the OUTPUT current of the welder in anyway relevant to the genset rating? The genset (or wall outlet) is providing the input voltage (high) at lowish amps. The welders transformer is converting that to low voltage /high amps.
As long as the genset can provide at least the same voltage/current as the wall socket, shouldn't that be enough?

[p.dath]

I get around 42kVA (no I am not joking)........but that sounds a bit high......mabey I am missing something about generators. But calc is (without power factor correction)
230 x 180 = 42KVA

You've assumed that the rod is being run at 230V while delivery the 180A of current. I think you'll find the "inverter" is delivery a much smaller DC voltage to the road. And it is that voltage you'll need to find. You'll also need to a a bit for the inverter loss.

Can you imagine if the welder really delivered 230VAC to the load how dangerous it would be?

[nadroj]

If you can run the welder out of a normal domestic socket, unless i'm missing something, this page http://www.dieselserviceandsupply.co...aspx#PowerCalc
gives a single phase, 230 volt, 16A with 0.8PF a kVa rating of 3.68. Are gensets rated differently?

+1
If the welder came with a normal 3 pin plug it will be 10A max, with a 3 pin plug with oversize earth 15A max or with a larger plug 20Aish.
The welder should have a nameplate with 230V (X)A.
A 4KVA generator will do the job unless it is something out of the ordinary.