Cebora 130 Turbo - Slower wire feed after generic drive replacement

[sanmarcopizza]

Hi all,

I bought a duff unit with what was supposed to just be a broken tension arm screw, but turned out to have stripped teeth in the gearbox. As I couldn't find replacement gears, I installed a generic 24V drive motor/tension assembly after fabricating a suitable box to offset it into the back board to allow for decent alignment with the gun hose etc. When attempting my first welds at the weekend I was a bit disappointed to find the wire speed, even when turned up to the max, seems much slower than I would expect, such that it continually suffered burn back when I was trying to lay a bead (0.8mm wire) on the flat of a piece of 3mm thick box section I was testing it on.

I know that this sort of fix on these machines is common, has anyone else experienced this issue, or have a possible fix? I am assuming at this time that the speed controller is working correctly.

Cheers,

San

 

[rikrobson]

I suspect that the old gearbox/motor was set to run at a different speed per voltage than the new one or the motor is a different power. The Power for the motor is gained from the welding voltage. This means that for a lower setting the voltage will be lower. One option would be to get the power from a dedicated transformer and rectifier. the drawback would be the wire speed will not change with the power settings.

Firstly I'd check the motors' ratings then check their reletive speeds. they may perform differently under load. Then I'd check the gear box ratio's, but this may be difficult if the gearbox is broken.

 

[sanmarcopizza]

Thanks for the reply Rik. It sounds like a lot of work, and probably still won't give me a resolution. I did read in another thread about using an extension lead and voltage drop, I was certainly using an extension lead when I tried it. That may account for a few issues I was experiencing. I have been using a disposable gas bottle but will get myself to BOC to pick up a Y size cylinder today so I can spend some decent time trying things out. I had a chat with a guy who did exactly the same mod to the same machine (which he had owned from new) using the same parts. He reckoned his machine worked really well, even better than the brand new Sealey that he had bought to fill the gap after his clapper arm broke and him doing the modification, so I am hoping that it should work.

 

[rikrobson]

In theory it should work the same. My feed was always good. The torch was more of an issue, but it was alot better after conversion to a euro torch. The only real issue with that was the distance between the rollers and the wire intake on the connector was a little large. This meant that if there was a kink or burnback then .6 wire would sometimes birds nest. To be honest I thnk that the .6 wire was more of a problem than a solution. I could still weld thin stuff with the .8 wire.
I'd get a meter on the motor connectors and get some proper readings. then run some wire to calculate the wire speeds.

They are a great little welder, I don't use mine any longer, but I still have it sitting on the shelf as an emergency backup.

 

[the snooper]

there are often a little variable resistor on the pcb that you can turn to increase or decrease the wire feed speed, have look for one

 

[sanmarcopizza]

Thanks for your replies. I got a Y size cylinder of argoshield light from BOC yesterday to replace the small disposable I was testing with. Replaced the wire liner, backed the tension off as much as I dare on the wire reel tensioner, ground the metal clean, ground the ends of the earth clamp and plugged directly into the mains without an extension. What a difference! Now a very happy chap.

 

[sanmarcopizza]

Some beads on 3mm section
Front and rear shots of a butt joint and some beads on 1.5mm (?) sheet. Messing with settings. Decent penetration, minimal warpage and no burn through. Result!

 

[rikrobson]

You are always better to have the wire slip than try and push it up a tube where it's stuck at the end.. it's easier to run a grinder over the tip and release a suckling wire the than remove a birds nest and remove and re0lace the wire