Contactor needed for old welder - Help!

[Alan]

Welder just started playing up , I bought this some time ago , with a problem . Initially it would feed the wire when the trigger was pulled but wouldn't arc . After a lot of help from this forum , i managed to reconfigure to single phase and took apart the contactor and cleaned it - this fixed the problem and it's been a very good welder and done quite a bit of work .

but now it's started to develope the same problem , sometimes it arcs straight away , others it feeds the wire and doesn't arc , so you get a messy start to any weld with bits of wire sticking out . I have tried to clean the contacts again , but they look worn and there's a crack in the housing .

I'm trying to locate a replacement contactor ( or contactor and coil ? )
The original contactor is an Arrow Hart 130 series , 3 wires in the top and at the bottom , with 4 connections along the front ( in front of coil ? ) The machine is an old Max-Arc 200 ( probably '70s or '80s )

can anyone suggest who to try for a replacement ? any help gratefully received . Regards Al.

 

[Robotstar5]

Do you know the contact rating e.g. 25Amp and the coil voltage?, a picture of it may help.

Any contactor with same values should work (might need to re-arrange wiring a bit), I tend to use Telemecanique when replacing contactors in the welders at work.

 

[mike 109444]

You might also find a diagram printed on the side of the contactor. May req gental clean to see details. Worth making a sketch of the diagram if it has one. Is it also possible that with three wires in and out that not all of the wires in/out are being used following the reconfig to single from three phase and so you may have spare (not being used) in/out amoung the three in/outs, just a thought. PS don't forget take lots of pics for reference or showing to possible suppliers.

 

[awemawson]

post a close up sharp focus photo of the contactor - it will help identification no end!

 

[Alan]

more info

Had a bit of think about it , and thought that it's more likely the moving parts in the contactor , otherwise it would either work or not , so took it apart again and checked the continuity between each top and bottom connection when the magnetic contact is pulled up . Two were consistant and one was intermitent , also , considering they were all cleaned on Saturday , 4 out of the six were blackened by arcing - suggesting they failed to contact fully .So removed the front of the unit to get access and took the contacts that are mounted on the panel ( the fixed ones ) out and put a 1mm thick washer behind them all - bringing all the contacts out , closer to the moving part operated by the magnetic switch . Refitted - and tested and it's fixed the problem for now . Although there's still the crack in the housing and if the contacts have worn , the moving part will eventually be U/S - so hopefully i've bought some time to find a replacement contactor . I know it's an old welder and some would think it's better to replace it , but i really like it and for what i use it for it's the nicest i've used .

Here's some info off the contactor and some pics :

Arrow / Hart
200/250
380/440 50Hz

130 Series ( serial number illegible )
For 3 phase 50A

600v 25hp
440v 20hp
220v 10hp

Aux sw msa131-220
Aux sw msa131-216
600v same pole
120v oppos pole .

Looking at it , I don't think the coil is actually connected to anything on the contactor - it's just mounted there (?)

 

[madkayaker]

thats an old beast! i would strip it down and clean all the crud out of it before ditching as none of the new ones will be as good as that

 

[Alan]

Pic.

Not a good pic , but this is what it looks like .