SAW Welding 1

[Behzad1210]

Hi
We are using a number of welding machines as automatic welders in a 4 wired (1DC, 3AC) SAW process in our company( Rolling and pipe industry).
Our machines are in two types:Lincoln US-DC-1500 and Lincoln US-AC-1500 and NA-5 and NA3/4 as wire feed controllers.
We are using them in VV (variable voltage) mode and our problem is current fluctuation.
In low thickness steel plates that welding current is low (under 500amp), fluctuation amplitude is lower than 40amp that can be ignored. But in high thickness steel plates that welding current is more than 800 amp, it's fluctuation exceeds 100 amp that as you know it will cause some defects in welding.
We want to know what reason or reasons can cause this problem and what is your recommeded course of action.

 

[waross]

If there is a PID controller or similar on the current, dial in a few more percent proportional band.

Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[AC-Power]

I had this problem sometime ago. I will check our office history to see what it is we did to correct it.

 

[waross]

I would look for a failed capacitor in the current control circuit.
What is the frequency of the fluctuation?

Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!