OK, Sounds like an adventure. Nothing to loose so I'll give it a shot and report back. I'll order a backup just in case. Glad it wasn't a 200 VA or larger. It's just a 12V for relay power.
Thanks.
Thanks.
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Need CSI DIY
I probably know the answer, but is there any way to salvage a toroid?
You know the story - " I should remove that toroid in case the drill grabs and........". The outer three layers are cut or distorted.
Not expensive to replace but I thought I'd ask the question anyway. Isn't quite the picture I had planned to post this weekend.
Don't worry, remove that resin filling by drilling and remove all insulation and upper layer of secondary. You can rewind it. I have done it for more expensive (hard to find toroidal Trafo). For outer layer secondary wont be more than 50 turns for 12V secondary. But you count it while removing from core. Otherwise you have to weigh that copper for same new wire.
For easily available transformer, go for new. It's worth only if something hard to find.
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Pass DIY Addict
Joined 2000
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Hi Bob,
Have a look at my DIY power filter where I had to modify a power transformer to adjust the output voltage. Same deal - carefully unwind, patch & repair, rewind...
Eric
Have a look at my DIY power filter where I had to modify a power transformer to adjust the output voltage. Same deal - carefully unwind, patch & repair, rewind...
An externally hosted image should be here but it was not working when we last tested it.
Eric
Note that all commercially produced cases for computers (desktops to rack servers) always have a fan extracting air out. This draws air through in a flow pattern with entrance and exit rather than causing hot air to circulate internally and having longer internal (dwell) residence time. Flow is simple in and out. Not in, swirl and circulate, then out.
Consistent with observations by Blink, sucking is better than pumping.
A similar example that you can see at work is on a hot day (no AC) put a large window fan on one window blowing in open other windows. It is nice and cool right in front of fan but nowhere else. Now put fan to blow out in window and open other windows. You will notice that cool air comes in through all open windows and hot air leaves house through blower fan pointed out.
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Note that all commercially produced cases for computers (desktops to rack servers) always have a fan extracting air out. This draws air through in a flow pattern with entrance and exit rather than causing hot air to circulate internally and having longer internal (dwell) residence time. Flow is simple in and out. Not in, swirl and circulate, then out.
Consistent with observations by Blink, sucking is better than pumping.
A similar example that you can see at work is on a hot day (no AC) put a large window fan on one window blowing in open other windows. It is nice and cool right in front of fan but nowhere else. Now put fan to blow out in window and open other windows. You will notice that cool air comes in through all open windows and hot air leaves house through blower fan pointed out.
this is ONLY when the heat can't go out on top.
as long as the heat can go out on top, it is better to blow cool air in.
Pass DIY Addict
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The only reason a "top" orientation would matter is if you are relying on buoyant natural convection cooling. If you use a properly sized fan, the ratio of forced convection vs natural buoyant convection is much greater than 1 and the natural convection is insignificant, thus the orientation of where to put fan doesn't matter. If you use a very small fan such that the forced convection is very little, then it helps to put fan at top (but then why use a fan?), but blowing out is always more efficient than blowing in. Like I said earlier, blowing in will give you cooler temps immediately where the inlet air impinges. Do you have measurements showing bulk air temps are lower for blowing in vs sucking out? I have yet to see a commercial box that has a fan blowing in.
There is an advantage to blowing in is that an air filter can be placed over fan grille to reduce dust buildup as positive pressure is maintained inside cabinet. For dusty environments, this would be preferable at expense of reduced cooling efficiency.
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thanks guys, these are well documented points. actually learning something here
There is an advantage to blowing in is that an air filter can be placed over fan grille to reduce dust buildup as positive pressure is maintained inside cabinet. For dusty environments, this would be preferable at expense of reduced cooling efficiency.[/QUOTE]
these are well documented points. actually learning something here There is an advantage to blowing in is that an air filter can be placed over fan grille to reduce dust buildup as positive pressure is maintained inside cabinet. For dusty environments, this would be preferable at expense of reduced cooling efficiency.[/QUOTE]
Farmer Hick thinks a fan lasts longer with ambient air going through it, than heated air.
more like = if you design your case for forced air cooling think about airflow and where you want it
if you want to differentiate for some reason in front or back......left rigt... up down... so on.
more like sucking out big hole. let different amount of cool air in different places
and guide the flow over the parts need cooling ... excuse my poor english.
What do you care about more? A $10 fan or your $500 (in parts and pieces -not retail assembled value) amp? Seriously though, a ball bearing brushless DC motor designed for continuous operation in these fans will run 7 to 10 years before breakdown.
xrk971.
look at any laptop man. no laptop in this world sucks air out
every fan that is mounted under blows air in. every fan mounted on the top sucks air out.
in almost any case with i front/rear mounted fan, the top lid has no vents, so they will be sucking air out(or one blowing in front and one sucking in the back).
you will not get the hotair sirculation with wents on top(hot air rises). but you also lose the ability to rackmount it.
look at any laptop man. no laptop in this world sucks air out
every fan that is mounted under blows air in. every fan mounted on the top sucks air out.
in almost any case with i front/rear mounted fan, the top lid has no vents, so they will be sucking air out(or one blowing in front and one sucking in the back).
you will not get the hotair sirculation with wents on top(hot air rises). but you also lose the ability to rackmount it.
Audio San,
I don't want to argue with you regarding basic thermal management concepts in engineering. And you are wrong, I have several laptops (Dell's) that have fans sucking air out - you can see the blades. They switched to internal fans with use of lower power chips that have heatpipes conducting heat to conveniently placed heatsink at exit of fan shroud internally.
I don't want to argue with you regarding basic thermal management concepts in engineering. And you are wrong, I have several laptops (Dell's) that have fans sucking air out - you can see the blades. They switched to internal fans with use of lower power chips that have heatpipes conducting heat to conveniently placed heatsink at exit of fan shroud internally.