Lincoln AC 225 update

[Billybuck]

I have 245V across the outlet, into and out of the welder on/off switch. The fan now turns (too slowly I think) but may be picking up speed (needs oil?). Voltmeter reads 80V from grounding strap or ground cable to electrode cable or from either of those to the selector switch, and 80V between the electrode holder and the work clamp. Since this is a voltage reading and not amperage, is it meaningless? I had done this between the clamp and holder when I first encountered no arc and got nothing. I'm wondering if it has "come to life". The fan has. Any other testing to do? I'm wondering if fooling with the outlet or the switch "fixed" the issue.

 

[RodinNS]

Usual problems with the old tombstone center around poor contacts in the selector switch (rotary dial)... and bad leads. Either one can show proper open circuit voltage when tested but not carry a lick of current because of lack of connection or broken strands in the cables. You need to inspect the cables very carefully through touch and bending over their entire length or anywhere you see mechanical damage.
The selector switch usually cleans up with some use and a bit of arcing...

Rod

 

[Billybuck]

Rod, the ground clamp chord has a tape covered gash in the sheath which did not sever the wiring. I'm surprised there isn't a device or method for testing the load carrying capacity of the components. Guess I'll strike it over the weekend and see what happens.

 

[Geo-TH,In]

A voltage and no amps usually means you have a bad connection some place. A voltmeter requires microamps to operate. Bet your 80v becomes zero when you try to make an arc.

Try using the voltmeter to find your problem. When you are making an arc, the secondary voltage will showing up across the bad connection. Make sure there is 220v going to the primary when you are making an arc.

It is also possible the bad connection is in the primary circuit. Look for hot spots, burnt connections, the on/off switch or selector switch.

The worst case, I was told the transformer on the newer Lincoln welders is made of aluminum. I once saw the transformer in the battery charger of a golf cart where the aluminum wires shorted out.

There is a chance the fan is 110v. Check the fan volts. That may be a clue that your bad connection.

LOL
George

 

[souNdguy]

i'd runt hat selector switch round and round.. and check the mains switch too.. any of those as rod mentioned could be prime issues.

 

[Jack L]

Soundguy and Rod are exactly right about the contacts being oxidized. My Lincoln buzz box sits so long that I have to rotate the amperage dial many revolutions to clean off the contacts.

Then it works fine until the next time..several months later.

Jack

 

[Billybuck]

I"ll go over the leads, clean up the selctor switch and give it a go. Thanks

 

[OH - 961]

(quoted from post at 13:54:54 06/29/12) I"ll go over the leads, clean up the selctor switch and give it a go. Thanks

The advice about checking continuity and switch contacts is right on. Just a methodical process to check everything. The fan is probably a 220 volt motor since it is probably fed directly from the main welder switch.

If the fan is running but slow, it probably needs oil. Most of the cooling fans use bronze sleeve bearings that are supposed to be "permanently lubed", but like anything else can dry out after a number of years.
I was able to resurrect a cooling fan in a Sears welder by re- oiling it. I was lucky to get it working again because I couldn't find a replacement motor that fit.

Myron

 

[Billybuck]

OH - it is 220 as you say. Oiled it. Not sure much improvement so far. I suspect it should be turning at a pretty good clip. Needs use for sure.