Contactor replacement

[Nick clarke]

Hi everyone
Having just bought a snap-on 130 turbo for the bargain price on just £20 on gumtree and then accepting that it didn't actually work, I stumbled on this site looking for people with similar issues.

Okay, so I had wire feed and gas(although I have since realised that the gas flows by depressing the gun regardless of whether or not the machine is switched on.

Lots of wiggling of wires and looking at lots of spaghetti wiring with no idea what goes where, I worked out that power to the gun is switched through a contactor. Some people suggested the feed to the coil was up to 24 volts. Actually i found out the hard way that my feed was 240 volts so beware of misinformation.

The contactor was getting 240 volts but was stone dead. Okay, this was good as I now knew what the problem was. The contactor is a Fantini Cosmi and is still available on line for around £70.00. Ouch, no way was I paying that for a machine that cost me £20!!. After a bit of further on -line searching for a 4 pole, 25amp alternative, a company called TLC-direct came up trumps. £13 plus delivery. Okay so I had to re-manufacture two new connections which link all the poles together just like the original from sheet steel but, hey if we're into welding what's a bit of fabrication. An Hour later all re-connected, and fingers crossed fired her up. Bingo, job done and welding nicely.

To sum up, £20 for the welder, £13 for the Contactor, and £18 to replace the broken carry handle. Total =£51.00. ....and I couldn't have done this without trawling this forum for advice and tips.

I've registered as a new member and hope to be a regular visitor.

Happy welding.

 

[RonA]

Hi everyone
Having just bought a snap-on 130 turbo for the bargain price on just £20 on gumtree and then accepting that it didn't actually work, I stumbled on this site looking for people with similar issues.

Okay, so I had wire feed and gas(although I have since realised that the gas flows by depressing the gun regardless of whether or not the machine is switched on.

Lots of wiggling of wires and looking at lots of spaghetti wiring with no idea what goes where, I worked out that power to the gun is switched through a contactor. Some people suggested the feed to the coil was up to 24 volts. Actually i found out the hard way that my feed was 240 volts so beware of misinformation.

The contactor was getting 240 volts but was stone dead. Okay, this was good as I now knew what the problem was. The contactor is a Fantini Cosmi and is still available on line for around £70.00. Ouch, no way was I paying that for a machine that cost me £20!!. After a bit of further on -line searching for a 4 pole, 25amp alternative, a company called TLC-direct came up trumps. £13 plus delivery. Okay so I had to re-manufacture two new connections which link all the poles together just like the original from sheet steel but, hey if we're into welding what's a bit of fabrication. An Hour later all re-connected, and fingers crossed fired her up. Bingo, job done and welding nicely.
View attachment 122610 View attachment 122611
To sum up, £20 for the welder, £13 for the Contactor, and £18 to replace the broken carry handle. Total =£51.00. ....and I couldn't have done this without trawling this forum for advice and tips.

I've registered as a new member and hope to be a regular visitor.

Happy welding.

I own a Cebora 130 turbo mig & from what I’ve read here & elsewhere the Snap on 130 & BOC 130 are all badge engineered version of the Cebora. As you mentioned the contactors are available through lots of electrical factors at a reasonable price.. When I repaired my friends Cebora I noted the contactor block is a multi contact device & the contacts are paralleled to handle the full 130 amps.
RonA

 

[Nick clarke]

Hi RonA
Seems like a good machine. Back to the Contactor, the original was rated at 25amp just like the one I replaced it with. If my welder is a 130amp, where is this amperage actually measured?. I presume it's not through the Contactor?

 

[RonA]

Hi RonA
Seems like a good machine. Back to the Contactor, the original was rated at 25amp just like the one I replaced it with. If my welder is a 130amp, where is this amperage actually measured?. I presume it's not through the Contactor?

As I mentioned above the contactor is a multi contact device & the 130 (max setting) amps are handled by the current being split between the multiple parallel contacts. Actually I seem to think my contactor block was rated at 30 amp per contact. That being said I don’t tend to use the full 130 amp setting much.
I’ve had my machine for getting on for 20 years now. If I could find fault it would be with the wirefeed, which I think could be better.
RonA

 

[daedalusminos]

The contactor will be switching the primary circuit i.e. txfmer primary at 240V

 

[daleyd]

Hi RonA
Seems like a good machine. Back to the Contactor, the original was rated at 25amp just like the one I replaced it with. If my welder is a 130amp, where is this amperage actually measured?. I presume it's not through the Contactor?

The 130 amp is after the transformer, so will be higher current but lower voltage.

The contactor operates on the supply to the transformer so will be the other way round (lower current but higher voltage).

 

[rtbcomp]

...
Back to the Contactor, the original was rated at 25amp just like the one I replaced it with. If my welder is a 130amp, where is this amperage actually measured?. I presume it's not through the Contactor?

Welcome to the forum.

They switch the primary of the transformer, so by fag packet calcs if the voltage on the secondary is 30 volts and that on the primary 240 volts the current in the primary will be 30/240 ie 1/8th that in the secondary. So at 80 amps welding current the primary will draw 1 amp, pro-rata up the scale. Neglecting inefficiencies, wind resistance &c.

 

[Nick clarke]

That's all double dutch to me but I'm reassured that all the replies suggest most people here know more about electricity than I Do! Should have studied harder in physics.

 

[slim_boy_fat]

Welcome aboard, Nick - can't beat a good 'work-around' to get something back from the dead.

 

[Nick clarke]

Hi slim_boy
Too true. It stands me around £50 so well pleased with result. I actually already have a cheapo Ferm 100 which still works well but it's nice to have an old classic as a back up.

 

[Nick clarke]

The 130 amp is after the transformer, so will be higher current but lower voltage.

The contactor operates on the supply to the transformer so will be the other way round (lower current but higher voltage).

Hi daleyd
That makes sense. Thanks for explanation.

 

[RonA]

That's all double dutch to me but I'm reassured that all the replies suggest most people here know more about electricity than I Do! Should have studied harder in physics.

As long as it’s working now, you shouldn’t really have to worry anymore about the innards, other than keeping the wire feed liner clear of any flaking welding wire coating. I’ve found 0.8mm wire gives a more consistent feed.
RonA

 

[Nick clarke]

I did buy a new shroud but it was a right pig to push/twist on. When I did managed to get it on the tip was recessed in at least 10mm and didn't look right. I needed mole grips to get it back off and refitted the original. It still does the job.