Welder diagnosis - please

[dannyp]

mosa seem to have a habit of doing this. i have one that did it, so dose a mate thev both just been used as a 240v genorator ever since had qutes to fix them but they were scary

 

[gaz1]

a posted post about the welder

mosa ts200

OK Great Memmeddu, i will check this well noted, and i come back to you. Thanks a lot. Nota : the LM348 becomes now giving a different voltage that's increase up by the potentiometer adjusting; but the strange is the pin q2 of TCA785P n°15 is at 0v and the q1 14 is having 3,6V 5KHZ the thing...

www.mig-welding.co.uk

 

[OldRigger]

Is it the older style without a PCB and welding current adjustment via a cable that controls the engine speed?

Yes it is.

 

[Hood]

Ok then in that case it is most likely the rectifier as said earlier.

You can start the engine and check the AC voltage going into the rectifier to make sure that is working. If it is then you can stop the engine and test the rectifier as per the posts above.

 

[the snooper]

No but you did properly

as it has an output as it powers things



however the user posted it within arc welding for a mig welding unit that is powered by a mosa generator

both users have come back and offered no advice on the post for the userhe d

Not getting into a discussion and hijacking his thread but he never mentioned it being used to power the mig, he had a 3kva Genny for that, he states the mosa has power for tools but no power from the welding side of the mosa's alternator, oh and i corrected your first line of your reply for you

 

[Wozzaaah]

I got the opinion hes trying to weld from the mig unit 240v side of it

theres no mention he was trying to arc weld with the mosa

Yes there was, he posted in the arc welding section and it was you who said it was in the wrong place.

 

[Hood]

Oh and just to clarify, the diode bridge mentioned by yourself earlier is a rectifier.

 

[OldRigger]

Ok, thanks for all the replies so far. I'll try and do some testing this week and report back.
So the first test is check AC voltage going into the rectifier If it is then check the diodes on the rectifier

 

[Hood]

Ok, thanks for all the replies so far. I'll try and do some testing this week and report back.
So the first test is check AC voltage going into the rectifier If it is then check the diodes on the rectifier

It is the first thing I would do as it doesn't require dismantling anything to test other than gain access to the rectifier and obviously make sure you don't get your fingers too close
I don't recall where the rectifier is, I seem to remember it being in beside the capacitors under the top lid but it has been at least 10 years since I had mine.

 

[OldRigger]

So what I didn't understand was that the diode bridge is the rectifier, a series of alluminium plates spaced apart. If so then they are behind the front panel but i may need to take the side panels off as well to get to the connection point.

 

[a111r]

 

[Munkul]

We had one of those old style TS200's, it burned the genny windings out. We used it for quite a while before that, to power a kemppi minarc 150, as the minarc was a much nicer DC stick welder than the Mosa!
We replaced it with a newer one with electronic current control, again we still use the minarc on it, and now the micorstick, because it's just plain nicer to run

 

[Memmeddu]

That is much more advanced than mine was, not a PCB to be had in mine To vary the current you altered the engine speed

As same as my little GenSet one

 

[Memmeddu]

Sorry this has got a bit confusing, to clarify

Mosa TS 200 is an engine driven generator and welder.
The generator side of it works but the welder doesn't.
The manual says to check or replace the diode bridge. I know where and what the diode bridge looks like and what a diode does (like a one way valve) i'm just unsure how to test it in this context.

If auxiliary power works diodes are not short .
And windings are good
That's for sure
Diodes might just blown open circuit.
They still need to be replaced but at least you're not cooking the windings.

Does the governor work?

 

[OldRigger]

If auxiliary power works diodes are not short .
And windings are good
That's for sure
Diodes might just blown open circuit.
They still need to be replaced but at least you're not cooking the windings.

Does the governor work?

Well i'm glad the windings are OK.
Does the governer work? It's a deisel, I don't think it has a governor, I may be wrong.

If the diodes are blown are they indentifiable and easily replaced or does the whole rectifier have to be replaced?

 

[Memmeddu]

Well i'm glad the windings are OK.
Does the governer work? It's a deisel, I don't think it has a governor, I may be wrong.

If the diodes are blown are they indentifiable and easily replaced or does the whole rectifier have to be replaced?

Governor should be there as well .
If you connect a load on the 240V side , engine rpm should change.
Can you upload a picture of your control panel?
I've seen some of those welders have a switch to change between generator and welder .
Might be not this the case but who knows .
Maybe it's just there the problem...
Anyway diodes can be easily replaced but can be a nightmare to remove them from the heatsink .
If your welder is electronic controlled you have both diodes and SCR on the rectifier .
I'm pretty confident that windings are ok because on such small units ,alternator has various output legs which come from windings ends .
These windings are in common for both welding and power generation .
If there is a short diode or blow capacitor it will not produce any voltage .
In this case you have auxiliary power so there's a good possibility that your welder has open diodes

 

[OldRigger]

This is the older model I believe. It does not have a PCB instead the welding current is dictated by the speed of the engine.

 

[Hood]

This is the style I had and also I think that is what the OP has. Very simple design and not much inside, bit like myself

 

[500e]

Separate winding's for the welder circuit used for welder only check AC to rectifier first
See next post

 

[500e]