Tradesmig 260-1 12 step position switch

[eddie49]

At first thought I would say no, the issue is somewhere else - such as a high resistance, caused by corrosion, in the low-voltage high-current welding output circuit.
When welding, is the power adequate to create a good weld, and roughly which of the power levels, from 1 to 12, does it seem to be fixed at?
As a first step to troubleshoot this fault, could you please measure the DC output voltage, positive on the torch tip and negative on the workpiece clamp? It should vary from about 15v to 38v, in regular increments, as you step up the switch positions. If the front-panel digital voltage display works, does it match the readings on your voltmeter?

 

[Ormondprop]

Finally got to spend a bit of time at this again, so my switch is faulty i checked it and on some settings i was getting continuity across several terminals and other settings i was getting nothing, so i ordered a new switch, i opened up the old one and found some of the cams had stuck in position and rotated out of sync with the centre notch rounded.
In the mean time though i dug deeper and found i’m not getting continuity across the transformer on the first 5 settings, i measured from the cables going into the 12step switch qf2 and to terminal 2 on km1 and was getting nothing from the cables in qf2 terminals 2,4,6,8 and 10 which i assume are steps 1-5, i’m wondering now should i cut my losses and cancel my ordered switch or is there anything common to these 5 settings where i might be loosing continuity, i checked any connections i could see and loosened them, sprayed contact cleaner and re tightened where possible.
The fact that the switch was throwing two poles at the same time in some settings have i damaged a transformer

 

[eddie49]

The fact that the switch was throwing two poles at the same time in some settings have i damaged a transformer

Yes, I am afraid that this may have happened.
This earlier similar thread, which has recently been revived by a repeat occurrence of the same issue, describes how a faulty switch caused damage ( in that case, to the external wires feeding the transformer coils ) :

N

Thread 'Kempomat250'

Nov 27, 2023

Hello guys,

I’ve bought a Kempomat250 today that needs to be repaired. Guy told me that the fuses blew when he put the welder on 3. He has also molten the wires leading to the transformer. Can someone tell me how to find the faulty component?

Thanks in advance

• Nielsie
• Replies: 27
• forum: Kemppi

As explained in Posts #20 and #22 of that thread, the "auto-transformer effect" means that voltage will always be induced in any coil of a powered-up transformer, and it will flow as short-circuit current if a failed switch joins two taps simultaneously.

 

[Ormondprop]

Thanks for all the help Eddie, fortunately i think i may have it sorted, today i temporarily put all my switch cables on strip connectors just to be able to manually switch my setting and test was it working on any settings before i cancelled my switch and due to pulling at the 12 cables going to the transformer i must have done something that fixed it, (hoping it must have been a connection inside the transformer u cant see that wasn’t making due to corrosion) but after pulling at the cables to fit into the connector strip i am now getting continuity across all cables, i tested several and seems to be welding fine and at the amperage jumps expected

Just need my switch to arrive now and get using it properly again and see will it stay working under load

 

[Ormondprop]

Also i came across these online and i’ll upload here incase anyone needs them, the manual and spare parts list

 

[Seadog]

If pulling them has made it work I'd be dubious as to its longevity.

 

[Ormondprop]

I’m thinking the same, but time will tell, does anybody know how them cables are tapped into the transformer, is there lugs or crimps inside the transformer, i cant see where they go and I don’t want to try get a look incase i damage some of the insulation on the windings

 

[eddie49]

A tapping on the winding of a transformer can be created by removing a section of the enamel or epoxy insulation from the winding wire and soldering a fly-lead ( which may be flex ).
However the more usual way ( especially if the winding is aluminium rather than copper wire ) is to pass the solid wire out through a hole in the side of the spool or bobbin, extend it to the connecting point ( e.g. terminal strip or rotary switch ), and then loop the same wire back in and continue the winding.
If this is how your transformer was built, you will see that only the start and final end are single strands of solid wire, all the rest of the tapping points will have two wires. The wires may be continuous, or they may have been cut and then stripped, with two wires clamped under each terminal screw.