industrial welder. any advice

[Darkwood]

Welding sets have been the bain of my life, more correctly idle welders who can’t be bothered with the return.

Cables on fire, bearings seized, you name it, they can bugger it up!

You and me too..been there posted some pics in the past ..seen welders take out 10mm bond in trunking melting into every other cable blowing main cutout... cost 6k to rewire and regardless of our warnings same guy did the same thing 2 weeks later - sacked instantly then and we had to re-do our work again albiet not as bad - 10mm earth and 600amps don't mix....

 

[Knobhead]

Sorry to say I’m out of here, the OP clearly doesn’t know what he’s doing. That said it doesn’t sound like the designer does either.

Heavy welding plant is dangerous and not for a trainee to be playing about with.

 

[Davey1988]

Length of circuit (25 meters),
max permitted Zs 0.31,
inrush current, max 80amps it runs off 50% power wave
power factor (unknown but the fuses are 80amp built in the machine 80amp max. N/A)
max permitted VD, 25m probs 2vd max. (No worries here)
ambient temp 30o
installation method E,
type of cable SWA 4 core.. I said the earth was copy my bad it's sheath, (was tired)
conductor operating temperature? 40 - 60o (90o cable)

Ohh and disconnect te required 5 seconds.


Tony your right I don't know about these but I'm the type of guy who likes to find out why it's this cable.

 

[Darkwood]

Take a pic of the plate Davey or supply the make and model of the welder, welders are not for the inexperienced as Tony quite rightly points out and require a lot of respect, some simple info you forget to mention or don't realise is important can be the difference between an incorrect install with issues to even a dangerous setup.

Welders can be designed for multi-tapped inputs and the plates can become confusing very quick, as a Trainee your enthusiam is great but you should be working under someones wing here and this is the person to answer your queries as (s)he's will have all the facts to hand as they have designed said circuit...

Your trying to win the marathon here just after you learned to walk, trying to understand this side of the job can make what your learning very confusing indeed as you'll see obvious conflictions to what your been taught so I would get yourself a good few yrs behind you before tackling such equipment.

I've seen seasoned Electricians mess up on machine/plant supplies just because they are clearly out of there depth, its not about just designing the supply, its also about knowing the peak and duration of power demands and how the loads work..... often is the case where you haven't got any info to reference as with most older plant.

 

[netblindpaul]

Any electric welding set made to current standards must not be able to "take out" any supply side earths etc.
If the set is not totally electrically separated between primary and secondary, then it does not meet the current build standards for it to be legal for sale, and if it is already in use then it is considered lethal by HSE & TWI I don't believe that the IET would argue either, and must be put out of service immediately as it is no longer considered compliant with PUWER98 nor EAWR89.

 

[mechelec]

Used to do some maintenance work for a small machine shop a few years ago. Had to replace bearings on one of his lathes on several occasions because he used to centre 2 pieces up on it and weld together. Problem was he would put the welders earth clamp on the body of the lathe and weld the piece in the chuck.

 

[Darkwood]

Used to do some maintenance work for a small machine shop a few years ago. Had to replace bearings on one of his lathes on several occasions because he used to centre 2 pieces up on it and weld together. Problem was he would put the welders earth clamp on the body of the lathe and weld the piece in the chuck.

Considering they make rotating earth clamps specially for this purpose then this bloke is an idiot, what he did there was dangerous both to personel and the integrity of the bearings.... they could have easily failed catastrophically after the damage sustained from the high currents bridging the bearings considering lathes can have heavy loads spinning with high inertia he is lucky he got nothing worse than bearing replacements... if thats true I'm truely facepalmed!!!!

 

[Geordie Spark]

Used to do some maintenance work for a small machine shop a few years ago. Had to replace bearings on one of his lathes on several occasions because he used to centre 2 pieces up on it and weld together. Problem was he would put the welders earth clamp on the body of the lathe and weld the piece in the chuck.

Things like that grind my gears!!

A Lathe is a precision machine tool and should be treated as such.

It is NOT a freaking welding jig!!!! :32:

 

[PEG]

Things like that grind my gears!!

A Lathe is a precision machine tool and should be treated as such.

It is NOT a freaking welding jig!!!! :32:

...Unless it's in a propshaft repair shop,in which case,that's mainly what it is!...albeit with running earth arrangements in place.

Any welding operation,carried out on machinery where current continuity bridges lubed slide beds and bearings,is going to be costly...:icon12:

 

[Knobhead]

https://www.youtube.com/watch?v=5JbnDXw-0pM

https://www.youtube.com/watch?v=-aEuAK8bsQg

 

[Darkwood]

https://www.youtube.com/watch?v=5JbnDXw-0pM

https://www.youtube.com/watch?v=-aEuAK8bsQg

Recently watched these for research for costing a design request where rapid welding of small parts was a requirement, the above wasn't the solution in the end but a modified stud welder - still waiting for go ahead to build this machine and will be interesting project if it comes off.

 

[Knobhead]

Any electric welding set made to current standards must not be able to "take out" any supply side earths etc.
If the set is not totally electrically separated between primary and secondary, then it does not meet the current build standards for it to be legal for sale, and if it is already in use then it is considered lethal by HSE & TWI I don't believe that the IET would argue either, and must be put out of service immediately as it is no longer considered compliant with PUWER98 nor EAWR89.

Never mind what any regulations say. The problem is bone idle welders clamping on to the nearest bit of steelwork and not the workpiece. Any electrical earthing or bearing in the return path will suffer.

 

[Knobhead]

Things like that grind my gears!!

A Lathe is a precision machine tool and should be treated as such.

It is NOT a freaking welding jig!!!! :32:

Just to upset you Geordie, I built a continuous spiral welder for refacing the steel rollers used in the foundry.

 

[Darkwood]

I work in a company that uses high velocity oxygen fuelled (HVOF) tech' to infuse a layer on metal coating on a steel drum fixed in a lathe not welding in the known context but has similarities .. one hell of a noisy thing and the UV off it is very intense and largely more dangerous compared to standard welding.

Its in a vented room due to the gasses used but resembles aluminium white welding light in a jet resembling a rocket engines output flame, its a new company on my rounds so will try get a pic or too as Engineering ****.
http://www.metallisation.com/products/hvof/

 

[Knobhead]

We used metallization gear for zinc coating ductile iron pipe. The spray heads are a pain in the arse, usually one head a week would catch fire.

I toyed with the idea of modifying one of the heads for the rollers but couldn’t get the required current for it to be reliable. The zinc heads were 1500A @20V.

So the MIG welder had to be pressed in to service for re-facing the rollers. It could build up the required diameter in one pass, the metal spray would have needed several passes. The beauty of the setup was once the roller was chucked the welding was immediately followed by machining by just changing the tool post.
I got in a spot of bother over the earth return. I pinched the brush gear off a spare motor on another plant, they weren’t happy.