Air in or air out.

[bigbassman]

I want to mount a small USB fan on top of a power supply as its on all day and gets very warm.My question is this..Do I mount it so that it blows cool air INTO the unit,or so that it sucks warm air OUT? Which is more effective? Thanx.

[wa10]

Forced positive pressure gives better cooling & less dust buildup than sucking air through a case.

[The Collector]

A blow job always gets the best result......fan-wise you perv's!

[bigbassman]

LOL Good advice guys.Thanx.

[bigpimp347]

when you consider PC's and most Ham power supplies draw air through then go with what they do.
but to be fair if they don't come with a fan, why do you think it needs one ?? are you an engineer ?

lets not forget forcing cold air on to warm hot surfaces causes dry solder joints.

same as the people who put fans on linears, if they come with a fan then fair enough but why fit one if it doesn't ?
correct operating tempreature and used correctly they shouldn't need fans,
my PSU's are on 24/7 only one has a fan as it came with one the others don't.
my repeaters are on 24/7 without fans.
only things i use fans on are my repeater transmitters.

[bigbassman]

Bigpimp,if I'd wanted a lecture I'd have asked for one,thanx.If you havent anything relevant to say,then keep your comments to yourself.I asked a simple question.I dont need one of your diatribes.

[cb4ever104]

same as the people who put fans on linears, if they come with a fan then fair enough but why fit one if it doesn't ?

The Zetagi BV135 doesn't have a factory fan , but my Syncron BV135 clone does . In some cases I think maybe the manufacturers cut back to keep the costs down . I don't see any real downside to adding additional cooling .

[bigbassman]

OK.Thanx for your input guys.Appreciated.

[bigpimp347]

Bigpimp,if I'd wanted a lecture I'd have asked for one,thanx.If you havent anything relevant to say,then keep your comments to yourself.I asked a simple question.I dont need one of your diatribes.

Ooh get you, got out the wrong side of bed ?

[Tim]

Blow not suck. A bit of equipment that has vents normally draw air through them, one that doesn’t, where a fan is fitted, blows air onto it but having said that some of the former also use a blow fan. A fan aids cooling and has no effect on the operation of the unit it’s fitted to other than to keep the component parts cool, in reality a cooling fan should not be necessary but operators have the habit of driving equipment as hard as it will go and it’s then that things start to melt, spark and go pop. With any equipment that heats up, such as a linear, you should not use it under load for long periods of time without allowing it time to cool.

[bigbassman]

Thanx Tim.My thoughts are,if it gets warm,then cool it.I just wanted to be sure what the optimum way was,Whether to suck wam air out or blow cold air in?

[Andy]

I remain to be convinced about the difference between blowing or sucking. Either way the same amount of air will pass through the equipment, and surely the same amount of dust will go through? I wonder if anyone has written a paper on it?

[bigbassman]

It seems a natural reaction to blow on something if you want to cool it,but also,sucking warm away would probably do the same thing,but doesn't seem as well...natural.Which is why I asked.But Ive mounted a fan on the P/S and all seems well.

[stanogs68]

It seems a natural reaction to blow on something if you want to cool it,but also,sucking warm away would probably do the same thing,but doesn't seem as well...natural.Which is why I asked.But Ive mounted a fan on the P/S and all seems well.

if it gets really warm try using a bucket of ice and sit it in that

[bigbassman]

Now why didnt I think of that? Simple!