Old SD Lee Stick Welder Problem.

By vaj4378 Date 11-24-2007 22:47

I have an old copper transformer type SD Lee Stick Welder (295 Amp).

Went to use it and the thing will not sustain an arc. Using standard type rod -- mild steel. I will spark like hell and stick the rod -- but not matter where I set the current setting, the unit will not sustain an arc. This has been a very easy unit to use in the past -- never a moments problem.

I cleaned the on / off switch and checked the voltage on the transformer primary -- only drops a volt or two under load. The output voltage is 50V open circuit, but goes to near zero when atempting to weld. The seconday winding is not shorted to the core and the resistance is very low -- less than a tenth of an ohm or so.

This unit has the thing that moves in and out of the core to increase the coupling between primary and secondary -- and the thing will stick and light up a rod on the higher settings so it is making good current.

Spark stabolization seems to be the issue here.

I think the rods are 7013 -- could this be the issue??? As I recall, I used to use 6013 rod material in 1/8" and up.

Could the thing have absorbed moisture in the movable core to cause this problem???

Wonder if any of guys have incountered this in the past.

Best Regards...

Steve in Tucson, AZ

By DaveBoyer (*****)

Date 11-25-2007 04:44

If there are any capacitors in this unit they need to be tested. Before You mess with ANY capacitor, You need to short the terminals to keep from getting shocked if it has stored a charge. You can give them a rough test by removing the wires from the terminals and testing with an analog [the old type with a needle] ohm meter set on low ohms. When You put the meeter leads on the terminals they should read infinant resistance. Then You reverse the leads. The needle should jump then return to infinant resistance. If oil is leaking from the casing, that is a bad sign. Additionally You need to make sure all the internal connections are making good contact. If there are wires that flex when that "thing" moves, be sure they are not fraying from the flexing. If You are using old rods that might not have been stored properly, try some new ones. I had a similar problem with My old Forny welder once, with the bad caps it wouldn't strike a usable arc.

By vaj4378 Date 11-25-2007 20:48

No capacitor in the unit. Just a transformer with a moveable core to change the current setting, an on/off switch and a fan.

It's one of the last all copper transformer types -- I would like to repair it if possible. Wonder if the 7013 rods could be the problem -- I used to use 6013 with perfect results.

Any other thoughts you might have are appreciated.

-Steve