jain ashish,

what means "continuously"?

Does it mean you're welding "more" than 6 minutes at a welding current of 350 Ampere, with a wire having a diameter of 1.2 mm (~ .047")?

Does it mean you are using the machine e.g. for weld overlay of large areas and the cycle time exceeds 6 minutes at 350 Ampere?

Does it mean that you are welding manually and perform "fusion welding" but not overlaying, e.g. fillet welds, having greater lengths?

Or does it eventually mean that the welding operation is a "semi-automated" one with duty cycles > 350Ampere and > 6 minutes cycle time?

In other words, you might provide a bit more information to receive the correct answer and to "help" us to "understand" your problem in an appropriate way.

Have a look upon the machine's power rating plate.

What height in welding current has the power supply with a duty cycle at 100 % (= 10 minutes)?

Let me make a guess...

Approximately 300... 310 Ampere?

Then make an estimation by your personal experience...

I would say "Yes" the wire, having 1.2 mm in diameter, is quite at the limit from the viewpoint of current density (working with a "saturated" spray transfer), at least under the presumption using 82Ar/18CO2 or a similar shielding gas.

The 250 Ampere at 60 % DC source is understandably a little to weak with its performance comparing both power supplies, and needing higher performance.

Just my humble opinion.

The others may correct me if I was wrong...

Best regards,
Stephan

EDIT: Sorry friends. Just even seen that " s s  wire" is used what I interprete as "Stainless Steel" whatever it means. Hence, I guess that 350 Ampere for a 1.2 mm wire electrode diameter might in general eventually be a bit too much. As I say it's an assumption. And of course then the use of 82Ar/18CO2 as the shielding gas is as well rather not recommended.