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  #11  
Old 09-24-2017, 05:16 PM
Normanby Normanby is offline
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Had a chance to look at the machine again recently and did the resistance test as suggested by GWIZ. The results did not seem good, the meter showed 10 M Ohms with paper under one set of exciter brushes, tried another meter which had a max 2M Ohms capacity and it showed overload. Took the paper out and rotated the unit a short distance and then another test with the paper back, this read 21 M Ohms. Maybe I am doing something wrong, if not what does this mean, bad joint somewhere or worse.
Have not done a flash re-excitation as suggested as the I was welding when the current stopped so don't think it would have lost its original excitation from the residual magnetism in the fields.
The copy of the manual is as received from Lincoln Australia, apparently the AS 400 was too old to be kept as a digital download so a paper manual was scanned and sent to me. I will try to attach some photos of the machine to give an indication of its general condition. There has been some rewiring done on the 240V side but most wire colors have faded so hard to tell.
Thanks for any more suggestions.
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  #12  
Old 09-24-2017, 11:44 PM
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GWIZ GWIZ is offline
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Your pictures are a big help, good job.

1) "Not the current problem"
But must be Cautioned
The Reactor "looks like" a spring is missing AND looks like the brushes are gone or shot. need a better picture ?

the caution part is if the spring makes contact with the surface or if to much current is drawn through the Reactor you will likely damage/burn-up the brush contact surface making the reactor unusable.

2) With the help of your pictures I have re-drawn the block drawing
Note I labeled the Reactor and Rheostat. ( the symbol they used for the Reactor is more of a rheostat symbol).

===
With your ohm readings yes you have an open control circuit.

As for resistance's these are just ball park figures that will help you to find the open.

The Rheostat should have the amount of resistance printed on its side or stamped into the center metal wiper plate.
with your picture I would guess between 50 - 100 ohms.

You have two Exciter field coils inside the Exciter.
Each coil would likely be less than 10 ohms each ( the two in series would measure as a total 1+1 = total)
And same for the exciters armature less then 10 ohms.

Then you have the two Shunt coils
I would guess less than a 100 ohms ( that is a big guess I never had to work on anything that had shunt coils)

Now with the paper still under one brush
place one test lead on the brush lead and probe each connection point until you get a reading.
Then
move the same test lead to the other brush and probe the connections and try to find where the open is.
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Last edited by GWIZ; 09-25-2017 at 02:14 PM.
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  #13  
Old 09-26-2017, 05:32 AM
Normanby Normanby is offline
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Default Really 400 AS

Hi GWIZ, Thank you for your interest in getting this welder sorted out. I managed to do a few more tests as suggested and some photos too. Re your drawing I placed paper under one set of exciter brushes and measured the resistance where the wire (4) comes out of the first shunt as 17.4 Ohms, then near the rheostat (the wiring includes a toggle switch and a 3 pin socket which can be seen in the photo of the front of the welder, don't know what this is for and switch had been up all the time I have had the welder) anyhow the wire (5) does not go directly to the rheostat but to the switch then back to the rheostat, measures 57.2 Ohms at the switch and 57.5 Ohms at the rheostat. I then measured the ohms on the wire at the connection for the moving contact at 77.7, all these readings with the paper still under the same brush. On the previous photo showing the rheostat there is a second wire connected to the moving contact which has a paper tape label "240V switch com", this black wire disappears into the main generator so will try to see where it goes to. Didn't have time to do more tests today but took a few more photos of specific areas. The reactor has 3 moving metal brushes with a spring on each, actual contact area looks thin, I should be able to remove these for inspection. The rheostat moving contact does not seem to have much tension holding down the contact, maybe the spring is soft. Any more comments and suggestions welcome.
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  #14  
Old 09-26-2017, 10:23 AM
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Ironman Ironman is online now
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Quote:
as suggested as the I was welding when the current stopped so
They all quit at some point when welding. Last one I worked on was a Hobart 300 that had a similar setup, an alternator exciter and a DC gen. There was a little 4-way bridge diode that fed DC to the fields that had popped.
Looking at your pictures, and as Gwiz says, you need to do some real servicing to that machine, and then it will do you for life. Don't know if parts are still available from Millar for it, but they are a pretty good company.
With the missing reactor coil, I can't see a nice weld coming from that, past the open spot.
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  #15  
Old 09-26-2017, 10:36 AM
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Quote:
as suggested as the I was welding when the current stopped so
They all quit at some point when welding. Last one I worked on was a Hobart 300 that had a similar setup, an alternator exciter and a DC gen. There was a little 4-way bridge diode that fed DC to the fields that had popped.
Looking at your pictures, and as Gwiz says, you need to do some real servicing to that machine, and then it will do you for life. Don't know if parts are still available from Millar for it, but they are a pretty good company.
With the missing reactor coil section, I can't see a nice weld coming from that, past the open spot.
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It is tempting to blame others for all this, especially those in control of the system, but don’t forget that for decades you voted for people who routinely lied before elections, and told you what you wanted to hear, that you could have it all right now and to hell with the future – well, that future has now arrived. Clive Maund

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  #16  
Old 09-26-2017, 11:04 AM
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terry lingle terry lingle is offline
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Gerry why would miller supply parts for a Lincoln machine?
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  #17  
Old 09-26-2017, 11:34 AM
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toprecycler toprecycler is offline
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Quote:
Originally Posted by terry lingle View Post
Gerry why would miller supply parts for a Lincoln machine?


Because they can help make it a better machine? lol.

In reality, I only have 2 lincolns, 2 hobarts, and a powcon in my home shop. At work it is all millers in daily current use, and very occasionally a Lincoln and a Hobart. They all are good machines since all are at least 17 years old up to probably 60 years old.


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  #18  
Old 09-26-2017, 11:34 AM
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Quote:
Originally Posted by terry lingle View Post
Gerry why would miller supply parts for a Lincoln machine?
Oh crap, my mistake, I was just on a millar site for some other stuff. Lincoln would supply parts of course, but I don't know how far back either company goes with support.
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It is tempting to blame others for all this, especially those in control of the system, but don’t forget that for decades you voted for people who routinely lied before elections, and told you what you wanted to hear, that you could have it all right now and to hell with the future – well, that future has now arrived. Clive Maund

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  #19  
Old 09-26-2017, 03:57 PM
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GWIZ GWIZ is offline
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Quite a few welders have a remote plug for a remote foot control.
Most will have a toggle switch labeled panel for "panel control amps" or remote for "remote controlled amps"
But most,
when in the remote position will also allow some control from the panel so you can set a maximum amps, so you don't over do it if you floor the foot pedal.

Its hard to say how yours is wired but "maybe" lets assume if in the panel mode the welder will stop welding without a foot control.

98% of the time the center lead on a toggle switch is com (common)
you can check which position the switch is in by checking for continuity with your ohm meter
one lead on the center (com) and probe the terminals on either side.

=====
I up dated the drawing somewhat.

you measured 17.4 ohms from points 1-4 (you have two exciter coils in series say 8 ohms each so 17.4 is about right)


Your rheostat picture shows markings of 64 ohms (measured across the two end terminals)

===
again keep the paper under the exciter brush so we don't measure a looped circuit back to the exciter.

you have two shunt coils in the main generator (in series) two wires exit # 4 & 5

measure the resistance across 4 & 5 basically checking to see if there is an open with with the shunt coils.
some other book states 42 ohms I don't recall if that was each or the two in series, if its the two then you may get a measurement of 84 ohms across 4 & 5.

If you get an open measurement then you have a problem.
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  #20  
Old 09-26-2017, 08:13 PM
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Quote:
Originally Posted by Normanby View Post

I placed paper under one set of exciter brushes and measured the resistance where the wire (4) comes out of the first shunt as 17.4 Ohms,

then near the rheostat (the wiring includes a toggle switch and a 3 pin socket which can be seen in the photo of the front of the welder, don't know what this is for and switch had been up all the time I have had the welder)

anyhow the wire (5) does not go directly to the rheostat but to the switch then back to the rheostat, measures 57.2 Ohms at the switch and 57.5 Ohms at the rheostat.

I then measured the ohms on the wire at the connection for the moving contact at 77.7, all these readings with the paper still under the same brush.

On the previous photo showing the rheostat there is a second wire connected to the moving contact which has a paper tape label "240V switch com", this black wire disappears into the main generator so will try to see where it goes to. .
Had to read this a few times..... if you probed from # 1 up to #7 and measures 77.7 ohms then,
IF, if I read this right your open line is between 2 & 7
you will have to work in the reverse and move your probe to the other brush and probe to the points on.
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Last edited by GWIZ; 09-26-2017 at 08:20 PM.
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