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swp mig 150 turbo
- Thread starter djpaulo
- Start date
Hello and welcome to the Forum.
For a MIG welder that only uses the simple Lo/Hi and 1/2 on/off rocker switches, this is an unusual fault. Multi-way rotary switches are more likely to fail. Anyway you have already replaced the switches....
An original fault in the wiring, or a short-circuit primary winding on the main transformer could cause this issue, but that is also unlikely.
The wiring is fairly straightforward. The mains Live and Neutral feeds will be fed to the moving poles of the two 2-way switches, one of them via a relay. The two fixed contacts of the switches will connect to the start and end of the primary, and to the two tapping points. The lowest output voltage of the single secondary winding will be produced by the highest number of turns on the primary, corresponding to "1" and "Min". The higher power ( i.e. voltage ) ranges will result from connecting to fewer primary turns.
The wiring diagram of a Clarke 100EN in Post #6 of this earlier thread will give a general indication of the typical arrangement:
To investigate the fault, I would suggest the following:
- for each of the four switch settings, measure the no-load DC welding output voltage from the tip of the MIG torch to the workpiece clamp.
It should vary in roughly-equal steps from about 15 volts to 25 volts.
- power off and unplug the machine and visually check that the wiring corresponds to the general description quoted here.
- if possible, check for any signs of burning or discolouration on the main transformer primary winding.
- measure the DC resistance across the primary winding at each of the four connections, i.e. from the start to the end, and from the start to each of the two lower-power tappings. The whole winding will have the highest resistance, corresponding as mentioned above to the largest number of turns. However, all the values will be very low, e.g. 2 Ohms, then 1.5, and 1.0 Ohms. If there has been an internal short-circuit in the primary coil, you would find the same resistance value even when connecting to different points.
For a MIG welder that only uses the simple Lo/Hi and 1/2 on/off rocker switches, this is an unusual fault. Multi-way rotary switches are more likely to fail. Anyway you have already replaced the switches....
An original fault in the wiring, or a short-circuit primary winding on the main transformer could cause this issue, but that is also unlikely.
The wiring is fairly straightforward. The mains Live and Neutral feeds will be fed to the moving poles of the two 2-way switches, one of them via a relay. The two fixed contacts of the switches will connect to the start and end of the primary, and to the two tapping points. The lowest output voltage of the single secondary winding will be produced by the highest number of turns on the primary, corresponding to "1" and "Min". The higher power ( i.e. voltage ) ranges will result from connecting to fewer primary turns.
The wiring diagram of a Clarke 100EN in Post #6 of this earlier thread will give a general indication of the typical arrangement:
First off, great forum ! i've been reading some interesting posts and carried out some tests from the info I have read, but would like further help on my welder that has just stopped working?
Problem: "Not welding / producing an arc"
The wire feed works when I press the trigger, the internal fan operates and the switch light illuminates.
I've checked continuity on the earth clamp back to the wire connection inside and it seems fine.
I've removed the rectifier that has a 4 diode set up (2 pair) and put a meter across each diode to check them, they all worked in one direction...
Problem: "Not welding / producing an arc"
The wire feed works when I press the trigger, the internal fan operates and the switch light illuminates.
I've checked continuity on the earth clamp back to the wire connection inside and it seems fine.
I've removed the rectifier that has a 4 diode set up (2 pair) and put a meter across each diode to check them, they all worked in one direction...
To investigate the fault, I would suggest the following:
- for each of the four switch settings, measure the no-load DC welding output voltage from the tip of the MIG torch to the workpiece clamp.
It should vary in roughly-equal steps from about 15 volts to 25 volts.
- power off and unplug the machine and visually check that the wiring corresponds to the general description quoted here.
- if possible, check for any signs of burning or discolouration on the main transformer primary winding.
- measure the DC resistance across the primary winding at each of the four connections, i.e. from the start to the end, and from the start to each of the two lower-power tappings. The whole winding will have the highest resistance, corresponding as mentioned above to the largest number of turns. However, all the values will be very low, e.g. 2 Ohms, then 1.5, and 1.0 Ohms. If there has been an internal short-circuit in the primary coil, you would find the same resistance value even when connecting to different points.
