Voltage Drop

By jwright650 (*****)

Date 03-08-2017 11:57

Is the work clamp making a good connection? Are you keeping the arc out on the leading edge of the puddle?

By Are Aye (*)

Date 03-08-2017 13:41

Yes Sir, we checked and all are in good condition. We performed several trials and still we encounter the same problem.

By Lawrence (*****)

Date 03-08-2017 12:22

HI Are Aye,

Please tell us more about your process.

Is your SAW operation DC and CV ?

Is your process AC and CV ?

Is your Process AC and CC ?

Are you running single or multiple electrodes from a single power supply?

What is your electrode wire diameter ?

Name your welding power supply

By Are Aye (*)

Date 03-08-2017 14:11

Hello Lawrence,

We are in pipe manufacturing industry.

Details for this project:

30in.OD 0.312mmWT API grade X65 (Spiral Pipe)

Welding: DC - AC
> Tandem wires - Inside and Outside weld,4.0mm electrode diameter
> Outside SAW Parameters: DC- 850Amps/28V, AC-500Amps./30V, Welding speed: 1.8meters/min., electrode distance: 15mm, DC-CTWD=29mm/AC-CTWD=31mm
> Flux and electrode German supplier.
> No Pre-Heat

Undersize Weld due to Voltage Drop (193k)

By welderbrent (*****)

Date 03-08-2017 12:54

A couple more questions:

Is the voltage drop between the power source and the arc?
Or is it from the electrical connection to the power source?
Are all the power leads to the power source and the work and electrode leads large enough to carry the load (amps) and are all the connections clean and tight? Check the leads just back from the connections while in operation. If they are getting more than just a little warm they are either not large enough or are too old and need to be replaced.

He Is In Control, Have a Great Day, Brent

By jwright650 (*****)

Date 03-08-2017 14:05

I'm with Brent, check the primary power coming to your equipment ....might be dropping before it gets to the welding power source.

By Are Aye (*)

Date 03-08-2017 14:34

Hi Sir Brent,

Based on the graph, we noticed this:
1. Current increases by 20~50 Amps (red line)
2. Voltage drop from 28 to 0 (blue line)
3. Wirefeed Speed drops the time (green line)

Actually this machines are new and we started operation mid of 2015.

By TimGary (****)

Date 03-08-2017 17:37

I would surmise that your voltage drop is a symptom of a root cause wire feed issue.

Tim

By Lawrence (*****)

Date 03-08-2017 19:02 Edited 03-08-2017 19:21

I agree with Tim G.

The picture helps as does the rest of the data.

Did you change contact tips ?
Tips in poor condition can cause this kind of electrical inconsistency, especially with CC units where this is really an adaptive feedback scenario with WFS. The kind of SAW you are doing is very high productivity most of the time. Large wire diameter will still wear an oval in even the most robust contact tip.

Wire kinks or no wire straightener employed.

Anything that inhibits the feed, including clogged liners, sharp bends in feed lines or even inconsistent wire diameter (think Hyundai)

I think your electrical issue has a mechanical cause.

By Are Aye (*)

Date 03-09-2017 05:19

We fully checked your points Sir Lawrence.

We replaced all fixtures such as feed rollers, straighteners, liners. Feed motors are in good condition too as per our maintenance group.
We change contact tips every time we set for trial and still we have this issue.

Thanks.

By welderbrent (*****)

Date 03-09-2017 13:18

You need to check and see if this happens when another piece of equipment in your facility is being fired off. A plasma table cutting parts. Another heavy welding system. If you are a pipe manufacturer I presume you have more than one production line. Even though each may be on their own breaker system they are all tied into the same power source from your electrical power grid. If that is not large enough then when one fires off while another is running the power draw at that moment could cause a drop in voltage to the equipment that is already running. Depending upon where the tie in is and how it is wired as well as the size of the other machines it may not be noticed in the reverse firing order. So when one of the others is already running and the one in question fires off it may not affect the other units.

Just a thought based upon all I am hearing. It sounds more like a power supply issue than a consumables problem.

He Is In Control, Have a Great Day, Brent

By PhilThomas (**)

Date 03-10-2017 01:51

If you have the capability - add input voltage to the welding power supply to your trace. You might be having intermittent site voltage issues.

By pipewelder_1999 (****)

Date 03-13-2017 00:47

Is there any corresponding change on the ID machine at all ? I would suspect input power fluctuation if its not occurring in a manner where it progressively gets worse.

By NealTaber Date 10-10-2018 17:53 Edited 10-24-2018 21:03

Hi...i want to know are all the power leads to the power source and the work and electrode leads large enough to carry the load and are all the connections clean and tight? Check the leads just back from the connections while in operation. If they are getting more than just a little warm they are either not large enough or are too old and need to be replaced.

printed circuit board assembly company