NS Dev
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 posted on 2/5/06 at 11:44 PM |
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Electrical question, TIG welder blowing trip
Finally got the TIG machine going this evening (just got in from the garage)
All ok except that once in every few "switch-ons" of the machine, it blows the MCB supplying the garage!
It's a 50 amp MCB so shouldn't blow too easily, which is worrying me!
In the very brief manual I downloaded for the machine (it's a used ESAB DTA 200 AC/DC machine) it mentions that if it blows main fuse (or trip I
guess) repeatedly, there is a faulty thyristor.
I would have thought if that were the case then the machine would always blow the trip, not just every so often.
Once it is switched on it runs fine, perfectly, with no probs at all!
Anybody got any ideas?
I thought it might be the inrush current with 2 huge transformers in the machine, and an overly fast trip, but 50 amps is still a lot!
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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nitram38
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| posted on 3/5/06 at 03:20 AM |
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Is the trip you are talking about an RCD or just an MCB?
RCD's protect against electric shock and work on leakage to earth. This may be the problem or if it is an MCB, it may be the wrong type.
There are A,B,C,D types. A being for circuits with low surge currents and D for high surge starting currents, like motors and welders. Although you
may only need a C type.
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NS Dev
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| posted on 3/5/06 at 07:41 AM |
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Ahhh brilliant, if that's the case that might solve my problem.
Yep its the MCB not the RCD that's the problem.
When you turn the machine on you can tell by the thud of the transformer whether the trip will pop, so I guess it is just the initial current that is
the issue.
I looked in the RS catalogue last night and didn't see any different types of MCB, but I'll have another look with a fresh mind today!!
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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tks
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| posted on 3/5/06 at 08:28 AM |
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if it has a transformer
then you always leak - read as loss - some current and thats what the device measures infact its a earth leaking detector. it measures the current
giveing and the current wich returns...
if they difference to much that it pops..
for home use they rate 40mili amps??
for industrial use have no idea..
any way it has to do with you CosPhi whis in fact is the factor of effciency the machine has.
Regards,
Tks
The above comments are always meant to be from the above persons perspective.
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NS Dev
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| posted on 3/5/06 at 09:53 AM |
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Cheers TKS but it's not the earth leakage breaker that is tripping, it is the over-current that is going.
Cheers Nitram, located a place with some C-type 50 amp mcb's in stock nearby, will pick one up this afternoon, pretty confident that will sort
the job.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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DarrenW
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| posted on 3/5/06 at 10:38 AM |
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I think i fitted a D-type when i had my big compressor. Local electrical factors should be able to advise / supply.
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NS Dev
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| posted on 3/5/06 at 11:13 PM |
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Cracking toast Gromit, 50 amp type C breaker fitted and hey presto, no more trips, thanks Nitram and everybody else too!!!
Welder is AWESOME!!!! 
Gave up playing with ally until I've mastered steel as I need that to sort the exhaust manifold.
Managed to run a bead on a steel beercan without burning a hole, just amazing control with this machine and the foot pedal control!!!
Another hour or do playing and I think I'll be ready to try my hand on the stainless exhaust collectors!
Then it's onto ally.. First impressions were.....flipping difficult!!! Can run a bead without filler and no burn through, but handling and
adding the filler is bloody tricky!!
Guess it'll come with time and practise!!
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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nitram38
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| posted on 3/5/06 at 11:22 PM |
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Although I am an electrician, I spent 5 years welding with mig, tig and arc, during the early 90's. You will soon pick up welding, especially
with foot control.
After you get used to it, you will be putting the footswitch to the floor on starting the ali welds and then backing off the right amount. Steel is
the opposite as you slowly increase current until you see the pool starting.
If you get the current just right, you will be able to feed the filler rods at your own pace. A common mistake is too much current and then chasing
the weld with the filler.
Good luck!
Martin
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