Lincoln 400 won't strike up an arc

[tyger006]

Hello again guys!

I have an older Lincoln 400 that was fine yesterday and now won't strike up an arc. It does make tiny sparks when attempting to strike, but won't grab or pull like it should when I strike. I checked my lead connections by connecting the leads to another welder and they worked fine. So I cleaned up the terminals where the leads connect and still no joy. I tried moving the dials all over and working them in case there was a problem in there, but still no luck.

What should I do next?

thanks!

Tyger

[cruizer]

A Lincoln 400 what?? Lots of 400's in the model name of thier welders.

[tyger006]

Sorry, that was very unspecific. Model SAE-400 Code # 10137HP diesel powered stick welder.

Thanks!

[cruizer]

Do you have auxillary / grinder power?

[acwd1950]

Have you tried it on high idle? I would check the brushes and commutators. Make sure that the brushes are not stuck and moving freely in the holder and the commutator are clean. My sa 200 does that every once and awhile if it sits for a few rainy days and its stored inside. Lock out the idle control burn a rod then its fine after that. Dont know if its got a bad connection somewhere or what.

Steve

[tyger006]

Do you have auxillary / grinder power?

I am not sure about the Auxillary power I will get back to you soon on that.

Have you tried it on high idle? I would check the brushes and commutators. Make sure that the brushes are not stuck and moving freely in the holder and the commutator are clean. My sa 200 does that every once and awhile if it sits for a few rainy days and its stored inside. Lock out the idle control burn a rod then its fine after that. Dont know if its got a bad connection somewhere or what.

Steve

Yeah, I have tried it on high idle. I guess we will have to get into the brushes and see how everything looks. Thanks!

[tyger006]

Do you have auxillary / grinder power?

No power on the aux. I havn't had a chance to check the larger fuse with a meter yet though.

[cruizer]

Kinda need a model code as there are 10 different SAE400's, so we can be on the same page here.

However, it should have a little 10 amp fuse just behind the right side front panel

[tyger006]

Sorry, that was very unspecific. Model SAE-400 Code # 10137HP diesel powered stick welder.

Thanks!

Yeah I had it in the above post. Sorry it wasn't the most clear.

The Fuses on the front panel ( I assume to the aux power) both tested out good.

Thanks

[tyger006]

Kinda need a model code as there are 10 different SAE400's, so we can be on the same page here.

However, it should have a little 10 amp fuse just behind the right side front panel

I think I found the one you are talking about and it was ok.

We found a fuse behind the starting panel as well (I think it was behind the engine protection/reset switch) and it was also good.

I took the cover off of the commutator and the brushes look ok to me (granted I am not a pro) and there was nothing jammed or binding as far as the brushes go.

Thanks again,
Tyger

[cruizer]

Well that only leaves your exciter rotor as being the culprit

[tyger006]

Well we are back online again! The trouble was a mistake rewiring a new Alternator over the weekend. The new alternator charges the battery perfectly and supposing that was it's sole function, I didn't suspect there would be a problem related to it. The mechanic put in a newly rebuilt alternator and wired it up the same way (to terminals that were in the same position) the old one was wired. The problem was that two of the posts on this new alternator were wired opposite internally. After talking to tech support at Lincoln, I learned that the alternator flashes the exciter to get it going, so we needed to make sure there was power on that line. Even though the terminal positions were the same as the old alternator, the terminal post the line was hooked to was not producing power and the terminal that wasn't being used by the old alternator is hot in the new alternator. So simply switching the line over to the hot side (hot when the alternator is running) and bang! We have arc again!

So Cruizer you are correct, it was a problem with the exciter, though fortunately not a worn or mechanical problem, just poor wiring.

Thanks for your help here on the board! And my thanks and admiration has to go out to Bob Crow at Lincoln- He knows these machines inside and out, and was perfectly professional in helping me with my problems!

~Tyger