Welding machine problems?

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stephena

Member
Location
oregon
We are trying to figure out why welders in a welding shop aren't working properly. Checked cord connections, voltage input, and anything else we could think of but the machines aren't running right and they are leaving worm trails. Anybody know what is going on?
 

Jon456

Senior Member
Location
Colorado
The first two things I would check are:

1. The quality of the ground connections between the work and the welding machine.
2. Voltage drop on the power supplying the welding machines while they are operating.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
The first two things I would check are:

1. The quality of the ground connections between the work and the welding machine.
2. Voltage drop on the power supplying the welding machines while they are operating.
How about the quality of the return connection from workpiece to welder? No need to involve " ground", and having any of that current trying to travel via earth (dirt) or EGC can cause problems.
 

Jon456

Senior Member
Location
Colorado
How about the quality of the return connection from workpiece to welder? No need to involve " ground", and having any of that current trying to travel via earth (dirt) or EGC can cause problems.
That's what I meant by item #1: the "work cable" which is connected to the workpiece and provides the return current path from the workpiece to the welding machine. Among welders, that's commonly referred to as the ground clamp or the ground connection.
 

Jon456

Senior Member
Location
Colorado
Another thing to check, if these are MIG welders, is the shielding gas flow. If there is no shielding gas (or insufficient shielding gas), you'll have lots of problems with your bead.
 

stephena

Member
Location
oregon
The votage drop while running is only 2V and 3V on some at worst. The ground clamp connection is good as well because they are actually permanently attached because the welding tables are so large. Both wire feed and stick welders are suffering from the same problems though! I'm really confused on this one.
 

kwired

Electron manager
Location
NE Nebraska
I have no idea how much impact this may have but is it possible high harmonics can be a problem?

Maybe need to look closely at both voltage and current and see if something is abnormal.
 
. Checked cord connections, voltage input

When this was done, was it done while the machines were running? (voltage input)

#1: the "work cable" which is connected to the workpiece and provides the return current path from the workpiece to the welding machine.

Did you test for voltage drop while welding between the welding table and the welder return connection? Also test the voltage drop on the electrode lead between the welder and the electrode.

The votage drop while running is only 2V and 3V on some at worst.

Is this voltage drop at the welder input or welder output? A quick test is to "short" the arc at the table and check for temperature changes on the electrode cable and connections as well as the "ground" cables and connections.

The ground clamp connection is good as well because they are actually permanently attached because the welding tables are so large.

See my comment above and check again!

Both wire feed and stick welders are suffering from the same problems though! I'm really confused on this one.

See kwired's post below.

This next comment is probably a long shot. Is this shop on utility power or a generator?

I have no idea how much impact this may have but is it possible high harmonics can be a problem?

Maybe need to look closely at both voltage and current and see if something is abnormal.

The possibility of harmonics being an issue is very large if all the machines are of newer vintage. When the welding "quality" tests were performed, did you isolate the other welding machines? Both on the input power as well as the outputs? Are there any other non linear loads like VFD's? Have the machines been tested to prove that they might be the actual culprits? I'm thinking some good testing would include taking the existing machines to another site to see if they work correctly and bringing a known "good machine" to the problem site.
 

stephena

Member
Location
oregon
The voltage drop I took is at the welder input. The welding return connection is good. There are no VFD in the shop just a ton of welders. It seems weird that multiple welders would suffer from the same problem so maybe there is an issue with the power quality. What's the next best step to addressing this problem? The shop is on the utility
 

steve66

Senior Member
Location
Illinois
Occupation
Engineer
Did the welders work at one time? Has anything changed?

Its hard to say what could be the problem. Its not necessarily an electrical problem (although I admit, I don't know what worm trails are.)

Maybe the guys they hired aren't so good at welding. Maybe the material they are welding isn't up to snuff. Or maybe they have bought cheap wire and rods.
 

Jon456

Senior Member
Location
Colorado
The voltage drop I took is at the welder input. The welding return connection is good. There are no VFD in the shop just a ton of welders. It seems weird that multiple welders would suffer from the same problem so maybe there is an issue with the power quality. What's the next best step to addressing this problem? The shop is on the utility
Does the problem occur when only one welder is in use and the others are powered off? Did you perform your voltage drop tests when only one welder was in use?
 

kwired

Electron manager
Location
NE Nebraska
The voltage drop I took is at the welder input. The welding return connection is good. There are no VFD in the shop just a ton of welders. It seems weird that multiple welders would suffer from the same problem so maybe there is an issue with the power quality. What's the next best step to addressing this problem? The shop is on the utility
Does this problem only appear when several welders are in use or does it improve if there is limited welding taking place? If newer vintage machines with electronic controlled output - the more you have going the more potential you have for harmonic issues.
 
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