Welder will weld for about 30 minutes and then will not weld until the unit cools down. generator function is normal. the repair shop told me that the welding leads were bad so I replaced them and have the same problem. the unit is a ranger 250 with chopper tech.

wrong
gasless mig welders are used the same as gas /wire migs
the only difference is the polarity of the leads to the hand piece and the work ground and this is indicated by the plug in the machine for the ground lead
what the "someone " would have been referring to is the duty cycle of the unit
every welder has a duty cycle because of the heat generated in the welding process by the electronic components and transformers and if that duty cycle is exceeded the machine stops working until it cools down or damages the circuits
it is stated as a % of time in use so a unit with a 20% duty cycle means that for every 20% of use it has to cool for 80% of time
as an example ---if you were using a stick welder, the time taken to burn the stick would be 20% and the time taken to insert a new stick and clean the slag off the weld to resume the process would be the 80%
It also depends on the amps being used for the weld
on a machine with 120amps capacity and you were using 15 amps to weld sheet metal--body panels - the length of welding time will be considerable compared to using 115 amps where the weld time would be a few minutes
there are plenty of helpful hints in the operators manual and other technical publications on line

If your Miller Trailblazer 302 AC/DC welder generator is starting and putting out electricity, but will not weld in any position, there are a few things you can check to troubleshoot the issue:

• Firstly, check the welding cable connections and make sure they are secure and clean. Check the cable itself and make sure there is no damage or corrosion.
• Secondly, check the welder's ground clamp. Make sure it's clean and tight, and that the ground connection is secure.
• Thirdly, check the welding gun liner, and make sure it's not blocked or damaged, this can cause the wire to feed improperly.
• Fourthly, check the wire feeder, make sure it's functioning properly, and that the wire is feeding smoothly.
• Lastly, check the voltage and amperage of the welder. Make sure it's set to the correct settings for the type of welding you are trying to do.

It's important to check the manual of the welder for troubleshooting steps and also check the warranty of the welder and see if it's still covered by the manufacturer. If you are not able to find the problem or if you are not familiar with welding equipment, it's best to take your welder to a qualified Miller Electric welder repair service center, they will be able to diagnose and fix the issue.

first thing to check is the over load reset button as all welders have a duty cycle for welding if that period is exceeded , the machine shuts down until it is cooled down
the duty cycle is the time of welding allowed in relation to the amps required to weld
for example with a 200 amp welder set at 200 amps with a 20% duty cycle for every 20 minutes of welding you have to allow 80 minutes to cool down
if however you have a 200 amp welder with a 20%duty cycle but it is welding at 20 amps then the duty cycle is extended dramatically other than that check for a fuse or take it in for a service

Motors and generators are the same in this sense. The winding of a field coil is defective. The winding heats up with use and the winding expands causing it to short out and quits doing it's intended purpose. An hour of cooling allows the winding to contract thus clearing the short circuit. A good motor rewinder person can find the defective winding with an oven or heat gun and can rewind it for a fraction of a new welder generator.

Sounds pretty normal. These units are not rated to weld continuously. They might only be rated at 5-10% for cheap welders and longer for better ones. They are never designed to run continuously. You need to get into the higher end ($$$) before you get that ability.
You can try to blow cool air into the unit to help it cool. Sometimes this can extend the work time.Basically you can try that or work to your temp cut off limit as you have been or upgrade to a better unit. That is about all you can do.

Your weldpack 100 has a duty cycle of only 20 t0 30%, meaning that your machine will weld for 2 to 3 minutes and then you need to let it cool down for the 8-7 minutes, then start again.
If the problem continues let me know.

these need a good power supply , i looked and did not see the duty cycle on this welder if you are doing heavy welding 100% power it will need 30- 40 minutes to cool of to weld again. it all depends on the units duty cycle, stated on the welder spec plate ..can you bypass the auto feed speed mode ? this might be the issue.. good luck ..use all the protection you can when welding these are like the sun and can and will burn exposed skin and eyes .. if'n i was any help throw me a bone and vote thanks jay

the unit will need to go in for service there is a control bord issue there 4 in the unit these boards have to be tested by Lincoln i have the same welder and what they will do is swap out the boards till the bad one found if the unit is not under warranty they can be expensive mine coast 500.00 for the 1 control board there is not a clear way to say it is a particular one do to there all inter linked as to functions. go to the web site and search for a service center in your area hope this helps

The transformer has an overtempature switch the shuts the welder down when its duty cycle is exceeded. After it cools, the switch will close and the welder will run again. However, you are not supposed to use the welder until waiting an additional cooling off period as specified in you manual(~10 min.).Also you are not suppose to weld beyond the duty cycle or damage could result. Especially if done on a continuous basis.

there is probley nothing wrong its called duty cycle.which means that if you are welding long periods or welding at max amps the welder will kickout to cool down.Look on your unit for the tag that tells imformation about your unit.It will show something like 30% duty cycle so that means you can weld 3 minutes at full power before the unit shuts down.