madkayaker
Pro sparkey Pro Welder
- Messages
- 13,678
Whats the back of the board look like?
- Thread starter malcolm
- Start date
malcolm
& Clementine the Cat
- Messages
- 9,676
- Location
- Bedford UK
Back of the boards look OK. But this is going to be embarrassing. 
I think I've got to the bottom of the unpredictable current. Or at least the current being lower than predicted. Guess who wasn't keeping an eye on the earth clamp connection to the work! With arc welding my practice piece got covered in a load of spatter and flux which insulates. Hopefully that'll have been the problem, as it seems to have been working correctly all afternoon.
The relay noise on start up seems to have stopped happening. Possibly it was temperature related. Happy Syncrowave again hopefully, though I've no idea why it suddenly decided to run at full amps this morning. But it only did that once so fingers crossed.
I think I've got to the bottom of the unpredictable current. Or at least the current being lower than predicted. Guess who wasn't keeping an eye on the earth clamp connection to the work! With arc welding my practice piece got covered in a load of spatter and flux which insulates. Hopefully that'll have been the problem, as it seems to have been working correctly all afternoon.
The relay noise on start up seems to have stopped happening. Possibly it was temperature related. Happy Syncrowave again hopefully, though I've no idea why it suddenly decided to run at full amps this morning. But it only did that once so fingers crossed.
madkayaker
Pro sparkey Pro Welder
- Messages
- 13,678
lets hope it was just operator error with the earth clamp but we all do it!
malcolm
& Clementine the Cat
- Messages
- 9,676
- Location
- Bedford UK
Well, turned out it wasn't totally operator error. I apologise to my last remaining brain cell for my false acusations.
Can define things a bit better now though. First weld of the day is really weak. On a setting of 130 amps I'm probably only getting 50 amps. Rod will stick a lot, but it's possible to get it going and lay a pathetic bead. It improves slowly by itself, but I can force it to nearly the right current by a quick blast at 250 amps (which will instantly work in a 250 amp sort of way). After that I can turn the current back to 130 amps and it's only 20 amps off and it stabilises to the right current with time.
My friend that designs superconducting electromagnets reckons dirt in some low voltage circuit. That would be difficult to diagnose. Spade connectors I have removed looked clean and they were very tight so I'd worry about snapping connections in circuit boards if I tested all of them. It feels like a bad earth so I'm thinking dirt somewhere in the output circuit. I'm measuring 60V (OCV) and I feel I should be measuring 80V, though I've not yet checked while things are good.
Ideas for cleaning and testing now much appreciated. I'm a bit worried the problem developed so suddenly. One day perfect and the next this. Suggests some tricky electrical component rather than a dirty connection to me. But what electrical bits should I be looking at? And which in your typical amp control circuit would get back to normal with a little heat?
PS: We tested the mains. No load 242V. Switch the big old thing on takes it down to 235V, and while welding it's 230V. So not that.
Can define things a bit better now though. First weld of the day is really weak. On a setting of 130 amps I'm probably only getting 50 amps. Rod will stick a lot, but it's possible to get it going and lay a pathetic bead. It improves slowly by itself, but I can force it to nearly the right current by a quick blast at 250 amps (which will instantly work in a 250 amp sort of way). After that I can turn the current back to 130 amps and it's only 20 amps off and it stabilises to the right current with time.
My friend that designs superconducting electromagnets reckons dirt in some low voltage circuit. That would be difficult to diagnose. Spade connectors I have removed looked clean and they were very tight so I'd worry about snapping connections in circuit boards if I tested all of them. It feels like a bad earth so I'm thinking dirt somewhere in the output circuit. I'm measuring 60V (OCV) and I feel I should be measuring 80V, though I've not yet checked while things are good.
Ideas for cleaning and testing now much appreciated. I'm a bit worried the problem developed so suddenly. One day perfect and the next this. Suggests some tricky electrical component rather than a dirty connection to me. But what electrical bits should I be looking at? And which in your typical amp control circuit would get back to normal with a little heat?
PS: We tested the mains. No load 242V. Switch the big old thing on takes it down to 235V, and while welding it's 230V. So not that.
