Blowing fuse when trigger is operated

The cooling fan motor is likely drawing to much current because it is worn out.

There is a temperature activated switch near the transformer that will turn off control voltage until the transformer cools. There is also a fuse for the control voltage. That would explain why the motor won't run. There's a possibility that the trigger switch in the handle is bad too.

Hi Paul
You have a faulty starter motor,Common fault on the c5 starter sounds ok but is drawing too much power,And blows the 20 amp fuse for ecm

i put a new motor on the welder an i have 9 to 12 vote coming to the motor but the motor wont run all works but the motor

Follow this Link:
http://www.clarkeservice.co.uk/manuals/mig_welders/migpro90_150te.pdf

Let us know if it was the right one.

More then likely you have a shorted component (positive or hot wire to ground). Verify that the gun/trigger assembly is in good shape and has no broken wires that are touching the ground or case (may have to disassemble). Thats the easiest thing to check, everything else is inside the unit and will take more sophisticated knowledge and equipment to diagnose.

Hi well if it is blowing fuses and you are using it on a suitable circuit breaker, a FUSE really isn't suitable, unless a special Motor type slow blow fuse, etc esspecially with this much current draw, anyway if this is occurring the device must be short circuiting after it arc's, accordingly i would imagine that one or more of the output semiconductors, is shorting at this time, the only way to fix this will be to replace these semis? & possibly the drive circuit too? It's impossible to actually tell without actually examining the unit as i am sure you must understand?
However DIY in reality isn't really practical, unless you can obtain a service and repair manual, and then you maybe able to isolate and repair the unit, however in my experience the very best thing you can do is take it to a professional and get a "Quote" as top prospective costings and go from there? This way at least you will know what's wrong and how much it will cost, it may even be that replacement is better than repair in any event.

Could be the cooling fan relay, the fuse, the sensor which triggers the cooling fan relay, or the wiring connections which join it all together. Is there power coming to the relay? Is there ground? Will the cooling fan operate if you trigger the relay? Try to break the circuit down in sections, and test a section at a time. If, for example, the fan operates when you trigger the relay, you will need to find out why the sensor is not triggering the relay. Maybe a bad wire? Or a bad sensor? Let us know what you find out. Good luck!

Some educated guesses:-
Check the operation of the radiator cooling and air conditioner condensor fans.- There may be a seized fan motor causing the current draw.
With such a major current draw I would expect a fuse to blow or circuit breaker to operate - check all fuses installed in system are of correct rating,

Check for damaged (heat?) wiring adjacent to exhaust/turbo fittings.

yes they should be connected to a thermo sensor