Series or parallel fans for max cooling ?

[FuZZ1L0G1C]

Jet-engine or wind-tunnel design?
My air-cooled 130 amp welding machine was recently purchased.
Works great for home projects such as work-bench etc. with one drawback – duty cycle.
The 5-inch (127 mm) diameter rear extractor fan cools the transformer while operating, up to the point where temperature rise (heavy or continuous welding) causes shut-down for 10-15 minutes.
As work/shutdowns progress, downtime overtakes work-time (20 min+) (transformer already hot).
My plan is to use external forced-air cooling to assist the built-in fan.
By boxing/ducting of one or more 8-inch 12-volt DC (CPU case) or 8-12-inch modified 220 VAC (floor-standing) fans, the assisted air-flow should increase the work-time.
However, I don’t know if parallel (as seen in wind-tunnels) or series (jet turbine engines) is more efficient, or same difference ….

 

[Bluejets]

All welders have a duty cycle to allow cooling in the transformer core.
I doubt any additional external fan cooling will have any influence as it takes time for the heat to radiate out to the surface.

 

[73's de Edd]

Sir FuZZ1L0G1C

To differentiate as to whether the time related fault is basically related to transformer OR control electronics.

Assuming that is not your only “toy” in the shop, try taking a 10 gallon or greater air source and reduce the regulators air output down to 30-40 lbs. and put on your blow gun attachment.

Then you have mamma-san, daughtersan or numbah won son then take air hose and have a close by air stream directed at the apex of the transformer core and winding.

This now presented air flow cooling capability should put your prior fans effort to shame.

Meanwhile, back in the jungle, you are busy laying a continuous bead to tax the system and also ready to note the onset of the shutdown, if now even being present, or if being somewhat delayed.

Then if querying if the relevant heat sinked components might actually be the fault, revert to an air stream closely played around heatsinking while you are then testing again.

73’s de Edd

 

[Tha fios agaibh]

You may be able to squeeze a little more working time out of the welder but it's not wise to exceed the duty cycle of your welder.
The manufacture has sized components based on this duty rating.

If you want to weld longer, it's best to upgrade to a higher duty cycle.

 

[FuZZ1L0G1C]

Thank you @Bluejets and @Tha fios agaibh for coherent to-the-point replies.
Yes, it does have a built-in duty-cycle (not a fault) designed for thermal protection.
I'll keep it 'as-is' as per helpful advice.
That is, if we have el-ec-tri-city in "the jungle".

 

[bushtech]

I have never had this problem with my old 180A air cooled welder. Suggest you try 73's de Edd's suggestion. He's normally right "on the money".

 

[FuZZ1L0G1C]

Hi again.
Re my original question re series (stacked) or parallel fan configuration.
Other than a Hoover Aquavac, I don't have any forced-air sources, 10-gallon or otherwise.
The welder cycle has since been explained by a qualified welder (rods too thick).
My curiosity from a purely scientific perspective prompted me to visit other forums, where this topic is in hot debate, following another members similar question.
So the jury is hung....
Thanks for advice given above, however.
Clive.
(PS - English-speaking white South African from Sandton).