trip, trip and trip again

[Mr J Morton]

After quite some time I've been using my Cosmo 170 again. I have found that once I can get the wire feed setup well I can lay down some decent welds, unfortunately that's only 10mins in every hour of welding. That I can cope with, but its started tripping the RCD on the fuse box, I also went through two fuses in the extension cable.

It happens when the trigger is pressed, with no arc, even when I'm just checking the wire speed. Then out of the blue it starts working fine for a few weld, then it trips again. I have a very understanding finance who stood by the fuse box for 40mins flicking the switch around 30 times. When it starts welding its runs fine even on its highest setting.

This all seems to point to the wire feed motor?

The fuse board also has a kiln running from it on 30amps so I assume that the supply is adequate, the extension cable I used is rated at 25amps and 4 meters long. The plug is 1 meter below the fuse box.

Any ideas how to fix this problem as it driving me (and the future Mrs) insane.

thanks Jon

 

[rtbcomp]

If it's tripping the RCD the fault is most likely to be on the primary side of any transformers in there, or a faulty transformer itself.

The first thing I would do is give it a good blow out with compressed air around the contactor and power selection switches in particular. (With the mains plug out!).

 

[Mr J Morton]

OK will do. I wont be using it for two weeks, but will try that before then. sorry to sound stupid but is that to blow out any filing etc which may be shorting it out?

 

[rtbcomp]

Yes, metallic dust or even damp dust could cause problems.

 

[madkayaker]

Rcd means its leaking to earth some leekage is normal but excessive is a danguras fault if you know a local spark ask them to pat test it and check leakage current

 

[Mr J Morton]

I forgot to feed back. A good blow out with air and its working great thanks for the responses.

Jonnym

 

[madkayaker]

thats good then