daleyd
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While that’s great advice, and not beyond the realms of possibility I’d say it was “unlikely” to be the root cause of multiple failures in short space of time?
- Thread starter Petroll75
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DAPPH
as dyslexik as I'm daft
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Make sure it is a dual beam oscilloscope not a simple drum & paper recorder . they popped a drum & paper recorder in by the meter ,,nothing showed , the sent an investigation team to ours disconnected every appliance or fitting and did a wee megger & resistance tests on each leg of the wires . they also checked every bit of electrical equipment we had ...Nada ,
After several hundred more outages the nex week I asked if they had a recoding dual beam oscilloscope .
Yep! they brought a few days later it and within the hour were recording milli second spikes of a thousand or more volts . They replaced the meter incoming over head back to the transformer as well as my consumer unit , and put in a new master switch with a Roxborough filer in it .
It cured my problems , but they were intrigued as to why the spikes kept happening , so investigated further. It turned out it was an engineering company with two heavy duty oil cooled welders doing two shifts a day .
I was at the end of the branch line so got their spikes and harmonic echo's every time they struck or broke arc's
DAPPH
as dyslexik as I'm daft
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From my experience , what blows a component may not actually be closely associated with the board the blow out occurs in . A simple hand-able over load in one area often translated to a deathly failure in different component elsewhere .While that’s great advice, and not beyond the realms of possibility I’d say it was “unlikely” to be the root cause of multiple failures in short space of time?
I agree. Metallic dust gets everywhere, especially with flap discs, and i reckon every welder uses them these days. Cleaning and blowing out machines, should be listed as routine maintenance I think. But, modern PCB should be totally epoxy coated, especially a welder?...All welding manufacturers must expect their machines to get covered in metallic dust surely? Especially modern ones with all their electronics.
daleyd
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Again, not disputing that at all but one failure after 3 weeks, another after 2 and another after another 3 weeks doesn’t point to it being dust related. Given that most of use have used the same or similar machines in pretty grubby conditions for years.
It may well be of course - but I’d think the chances of it being so are pretty slim.
That’s not to say your advice about keeping it clean and covers isn’t good advice…
As a computer support engineer I sometimes went to sites that thought their IT issues were caused by duff mains supplies. Usually it was actually the computer that was faulty, but we sometimes had to rent power monitoring equipment from a company called Dranetz to confirm the mains was OK.
A well-designed welder will have a "tunnel" airflow that only passes over the heatsink fins, not the PCBs.
Not epoxy, but a type of varnish known as Conformal Coating.
A well-designed welder will have a "tunnel" airflow that only passes over the heatsink fins, not the PCBs.
Although, as they say, a little knowledge can be a dangerous thing. The one positive out of this mess is that I've been reading a little about electronics, that previously I knew nothing about. I now know what a capacitor and zener diode is...well kind of! Lol.
Apparently the capacitors will charge at a certain multiple, say 1.6x incoming voltage. And are rated for a certain range. But if the incoming is greater (or lower) than expected, the effect is multiplied. They'll handle it, but a little damage may be caused. If this situation continues eventually they break. Seems to be my situation? Every machine worked well, for almost the same period of time.
Apparently the capacitors will charge at a certain multiple, say 1.6x incoming voltage. And are rated for a certain range. But if the incoming is greater (or lower) than expected, the effect is multiplied. They'll handle it, but a little damage may be caused. If this situation continues eventually they break. Seems to be my situation? Every machine worked well, for almost the same period of time.
Years ago I had an issue with my power supply, I had a UPS fitted to my computer when I first bought it and it monitored the voltages in the lines and batteries. The reason I got the UPS was we were in semi rural area and had constant power failures. Then after a few years it stated to show large voltage differences in the line which were recorded on the computer, which varied from 200V to 275V. I called the local power provider and showed them the recorded voltages. They went out to the local transformer in the street which provided power to our street and put a monitor on it. Turns out it was faulty and promptly replaced it, end result, constant power supply from then on.
Brad93
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In the past i've seen machines fried because the current took the shortest path of least resistance.
For example. Welding bench bolted to floor, rebar in floor, welder pushed back against well, metal chassis of welder touching steel
column.
The welding current had been travelling through the bench, through the rebar, through the column and into the machine.
Just check you have no continuity between the earth clamp and the chassis/body of the welder. And also no continuity between the earth clamp and the earth of your 240v circuit
For example. Welding bench bolted to floor, rebar in floor, welder pushed back against well, metal chassis of welder touching steel
column.
The welding current had been travelling through the bench, through the rebar, through the column and into the machine.
Just check you have no continuity between the earth clamp and the chassis/body of the welder. And also no continuity between the earth clamp and the earth of your 240v circuit
chrismac
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Some manufactures do have this in their maintenance, but its use a brush rather than compressed air. we all use air though
Erie Fred
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This is a very important point ^^^ I was in a shop that was having problems, and it was traced to some ground currents.
"Ground" is not "work".
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Not on production welders though as the operators would soon have them open looking for things to "adjust"
plus anything with dangerous voltages should only be accessible with tools.I used to take about an hour to service one of our welders.
Wow!..I wouldn't have thought it was possible. But I guess electricity always find a way!. I suppose this could happen quite a bit with portable units in automotive industry.
My case definitely can't be. Machine on a trolley away from bench. Definitely no rebar in the concrete floor as I poured it years ago
