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Drains
Yeah, nah.
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Interesting take on it Malcolm. I think you'll find that any airflow through the set will draw in dust...
The difference, generally, between forced draft and induced draft into/out of a box (rather than a duct), is that a forced draft tends to be directional, eg the airflow will be directed linearly (axially) from the fan.
The induced draft fan will tend to suck from a wide area.
So to decide whether the fan should be blowing in or sucking out, you need to work out where you want the flow of cooling air.
If you have a small number of components that you want the fastest airflow over (for the most cooling), then blow the air onto them.
If you want general air movement throughout the box, without any specific component receiving a good old blow, then suck the air out.
On my small arc set I elected to blow, not suck, at the airflow blows direct onto the transformer.
As a wee note, my Lincoln 300A set has a fan that's maybe 18". I noticed it was sucking. IMO, not the best, so I reversed two of the phase wires (it's a 3 phase machine), and now it blows direct into the set. Nothing else changed with the polarity reversal. I think it would have been fine either way.
Finally, to test effectiveness, operate the fan and place your hand in the drawn air flow, then the blown air. Which cools the most?
Edit - none of the above suggests than MIG Welder manufacturers position their fans to blow or suck. I think you'll find both are common, but Weldequip or DIY will know for sure.
malcolm
& Clementine the Cat
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My thought is a concentrated air flow would suck in dust more than a distributed air flow through all the various gaps.
I'm just back from the workshop where I conducted a very scientific experiment involving a Portamig, a SIP (turbo of course) and a fag paper. They all blow outwards from the welder. Though blowing inwards would be better for cooling.
How about the best of both worlds - blowing in, but sucking through an air filter. You'd need some nice louvres in the side to let the air out. And a custom paintjob.
Rusty
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Suck or Blow
I bought a secondhand Migatronic 221 some time ago and the previous owner fitted a fan to the underside of the chassis blowing air directly onto the transformer,the first time i used the welder i noticed how distracting the sound of the fan was when welding and also it acted like a Hoover on the floor of my garage ! when it sucked up a small plastic bag off the garage floor and wrapped itself around the fan blades the noise frightened me to bloody death !
so as the machine comes as standard without a fan and i only use the machine on low amps i disconnected the fan ( ah silence is golden )
If you do decide to fit a fan think about the positioning of it for the above reasons.
I bought a secondhand Migatronic 221 some time ago and the previous owner fitted a fan to the underside of the chassis blowing air directly onto the transformer,the first time i used the welder i noticed how distracting the sound of the fan was when welding and also it acted like a Hoover on the floor of my garage ! when it sucked up a small plastic bag off the garage floor and wrapped itself around the fan blades the noise frightened me to bloody death !
so as the machine comes as standard without a fan and i only use the machine on low amps i disconnected the fan ( ah silence is golden )
If you do decide to fit a fan think about the positioning of it for the above reasons.
Drains
Yeah, nah.
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Malc, didn't the fag paper get sucked in AND blown out?
The problem with an air filter is that axial fans can only work on a very low pressure drop, so when you introduce a restriction like a filter, the airflow decreases dramatically.
I get your point about dust, in terms of air speed. If air is being sucked in through every orifice then entry speed will be lower. Conversely, if the unit is pressurised by a forced draft then air will be squirted out of the various orifices, which may (or may not, probably not, thinking about it) keep the dust in suspension. I'd argue that any box that allows the air speed to drop would allow dust to fall out of suspension and settle on those precious parts...
The only really useful suggestion I can make is to position the fan to add to the effect of natural airflow, so a sucking-in fan goes low and a blowing out fan goes high.
The problem with an air filter is that axial fans can only work on a very low pressure drop, so when you introduce a restriction like a filter, the airflow decreases dramatically.
I get your point about dust, in terms of air speed. If air is being sucked in through every orifice then entry speed will be lower. Conversely, if the unit is pressurised by a forced draft then air will be squirted out of the various orifices, which may (or may not, probably not, thinking about it) keep the dust in suspension. I'd argue that any box that allows the air speed to drop would allow dust to fall out of suspension and settle on those precious parts...
The only really useful suggestion I can make is to position the fan to add to the effect of natural airflow, so a sucking-in fan goes low and a blowing out fan goes high.
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Air dusting gun, once a month, give it a good blow out (do it outside!) and job s'agudden.
Always an idea to take the cover off every so often and give it a propper clean; depending where your welder is used, it can accumulate greasy dusty sh1te which sticks to everything reducing the duty cycle and melting when it gets hot!
Always an idea to take the cover off every so often and give it a propper clean; depending where your welder is used, it can accumulate greasy dusty sh1te which sticks to everything reducing the duty cycle and melting when it gets hot!
irondarren
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welderpaul is right a good blast out with an air dust gun, is kind of essential maintenace, the dust acts as a heat insulator and as paul says will reduce duty cycle
rtbcomp
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On equipment I used to work on the fans blew into the bottom of the cabinets with filters on the inlet side of the fans. Air was expelled from the top. This arrangement means the natural convection and the fans work together.
This way all the air was guaranteed to be filtered. As mentioned sucking out of the cabinet means that air enters through all the gaps.
This way all the air was guaranteed to be filtered. As mentioned sucking out of the cabinet means that air enters through all the gaps.
malcolm
& Clementine the Cat
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I've got an electrical friend to keeps moaning about modern electrical design. Especially in computers. He's on the same wavelength as rtbcomp and removed most of the fans from a modern computer to make it run cooler!
There's a lot to be said for using rising heat to aid cooling.
There's a lot to be said for using rising heat to aid cooling.
southwestwelding
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Hi
Fans for mig welders usually blow out from the back of the welding machine. They are usually fitted at the back and draw air through the machine to mainly cool the rectifier, and discharges the warm air out through the back of the machine. Larger machines have two fans operating togethe in the same direction. I have sometimes reversed the flow of one of these fans to re-circulate the air as an experiment. It is probably best practice to have the fan(s) blowing out of the back of the welding cabinet. Please ensure the grills are kept clean and any filters are washed in warm soapy water before replacement.
Best regards
and good luck George
Fans for mig welders usually blow out from the back of the welding machine. They are usually fitted at the back and draw air through the machine to mainly cool the rectifier, and discharges the warm air out through the back of the machine. Larger machines have two fans operating togethe in the same direction. I have sometimes reversed the flow of one of these fans to re-circulate the air as an experiment. It is probably best practice to have the fan(s) blowing out of the back of the welding cabinet. Please ensure the grills are kept clean and any filters are washed in warm soapy water before replacement.
Best regards
and good luck George
rtbcomp
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Another point is that if you blow into a cabinet the pressure increases and so does the temperature of the air. If you suck air out the pressure in the cabinet drops and so does the temp, thus there is an extra cooling effect.
In real life it may be insignificant though??
In real life it may be insignificant though??
