Hi guys any ideas what the problem could be with my welder as it blows the main fuse which is a 40amps on the main distribution board without welding, just by pressing the button on the high setting on number 5 & 6. also, when I try to weld its seems that their lack of penetration on the material. This machine is a single phase one any ideas or suggestion for this problem thank you
- Thread starter popeye59
- Start date
It could be a fault on the rectifier. Blowing the 40A fuse indicates shorted diodes. On the other hand, low penetration indicates open-circuit diodes...!
I would suggest measuring the DC output voltage from the torch tip to the workpiece clamp, at each setting of the rotary power switch.
It should vary in roughly-equal steps from about 15v to 35v. I appreciate that you probably will not be able to check the high settings because the fuse will blow!
Then switch off and unplug the machine, remove the covers, and examine the connections from the secondary of the main transformer to the rectifier. There will probably be two heavy solid copper or aluminium wires bolted to the AC input tags on the aluminium-finned rectifier. Unbolt one of these wires and move it out of the way so that it does not touch anything. Then repeat the test mentioned above, but this time check the AC voltage output from the secondary of the main transformer. One of the two connections will still be bolted to the rectifier, and the other will be the one that you have temporarily opened. Again, you should see from about 15v to 35 or 40v, but this time it will be AC.
If you can now trigger the machine on at the higher power settings without the fuse blowing, this tends to confirm that the rectifier is shorted.
If you need help identifying these connections, please post some internal photos of the welder.
I would suggest measuring the DC output voltage from the torch tip to the workpiece clamp, at each setting of the rotary power switch.
It should vary in roughly-equal steps from about 15v to 35v. I appreciate that you probably will not be able to check the high settings because the fuse will blow!
Then switch off and unplug the machine, remove the covers, and examine the connections from the secondary of the main transformer to the rectifier. There will probably be two heavy solid copper or aluminium wires bolted to the AC input tags on the aluminium-finned rectifier. Unbolt one of these wires and move it out of the way so that it does not touch anything. Then repeat the test mentioned above, but this time check the AC voltage output from the secondary of the main transformer. One of the two connections will still be bolted to the rectifier, and the other will be the one that you have temporarily opened. Again, you should see from about 15v to 35 or 40v, but this time it will be AC.
If you can now trigger the machine on at the higher power settings without the fuse blowing, this tends to confirm that the rectifier is shorted.
If you need help identifying these connections, please post some internal photos of the welder.
