Hi guys , hope someone can help.
We have 4 Miller Summit Arc 1250 units with HDC 1500 DX control boxes that constantly give us trouble when initiating weld. Voltage seems to flare up uncontrollably before ( if were lucky ) settling down .
Problem seems to most prevalent with 2.4 S/S wires but will also occur with 3.2 S/S and carbon wires. WE use units on DC only as AC has been even less reliable. These machines are about 3 years old and have been problematic since new. Any Ideas out there
Thanks in advance, Steve.
Cutting the electrode on an angle to a sharp point was helpfull to me.
Whats your start mode wire speed? You may need to slow it down. Allow the arc to initiate and then increase to weld speed. This is essentially what the start modes are for.
Wow, talk about taking one back in history. Try running the wire down on a small ball of steel wool (you can use SS wool for the SS welding application) prior to starting flux flow and pushing the start button. Just enough pressure to hold the steel wool in position, with about 1/4 to 3/8 inch standoff of the wire from the work surface. There is not enough of the steel wool to cause any type of problem with the weld.
Let me know how this works for you. Old trick from way back when.
Thanks guys but perhaps I didn't explain to well . The arc will start but often for the first 15 or 20 seconds (sometimes longer) the voltage will go straight up to 60v plus before settling to the preset 28-30 volts. often if
the current (wire speed) is set low ie under 400 amps , the voltage wont settle at all. About the only work around has been to increase wire speed considerably for the first few inches of weld ( not so good when blow
through is a risk , and not always successful ) or swap to another weld boom and power source, usually a red one. Maybe these things just aren't meant to run low currents.
What values do you have programmed in your controller?
Preflow
Run-In
Start
Weld
Crater
Burnback
Postflow
Have you been in contact with miller?
We ran into a similar problem before. It almost sounds like a poor electrical connection causing the power supply to "search" for the right output.
I'm wondering if your contact tip is making consistent contact- so that after the 15-20 seconds it heats enough to expand and improve the electrical contact.
Do you have the straightener set to keep a little bit of the cast in the wire so it makes good contact with the tip? Is your contact tip ID just slightly too large?
By Steve.E 
Date 03-27-2008 09:37
Edited 03-27-2008 22:59
Had a bit of a play with a couple of these machines today one with 2.4 monel trying to run at 250 amps no luck at all. finally swapped power source only to a 1250 Dimension and had good results immediately.
Second machine 3.2 316L only way I could get good start was to increase wire speed to 95 in/pm then slowly turn down to 75 , even turning down to quickly would have the voltage spiking.( R Beldyk ) Run in setting was Auto, others should not come in to play. (C H Guilford ) I think you may be right about the machines searching for output, these units have voltage sense leads which my sparky assures me are correctly wired though I'm not so sure, miller instruction book is very sketchy with info. As far as Miller Australia those guys think I should know more than them, very disappointing.
