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Old 11-22-2020, 11:44 AM   #1
LearningToRepair
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Default Does power supply have to have metal case?

Hi!

I was thinking of making custom case for power supply. It currently has one small 6 cm fan which needs high rpm in order to keep it cool. However this makes it noisy. I had a thought that I would 3D print a larger case that have 2x 12cm fans that I would run with low RPM to keep them quiet. I figured that it is easier to 3D print a new case than do it from metal because I dont have tools to make precise cuts, bend it to right angle weld screw mounts and so on.

Would something be wrong if I 3D print plastic case instead? For example is it required to shield from radio waves or something or will it work just as fine in plastic case?

Some screws that connect PCB to case are connected to fault ground. I guess these I just have to wire connect to ground?


Has anyone ever attempted to build a custom case? Any success?
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Old 11-22-2020, 01:43 PM   #2
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Default Re: Does power supply have to have metal case?

Is this a computer switching power supply mostly in metal cases ( I do not have an answer for you about this type of switching power supply I do not want to give you the wrong information )

Or is just a switching power supply because this type of switching power supply are mostly made with plastic enclosure
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Old 11-22-2020, 03:31 PM   #3
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Default Re: Does power supply have to have metal case?

switching power supplies are in metal boxes for screening,
not to protect them, but because they are the source of rf noise.

if you dont use radio or give a shit then it will be fine in plastic - they used to sell coloured acrylic shells to customise pc psu's.
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Old 11-22-2020, 06:04 PM   #4
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Default Re: Does power supply have to have metal case?

aluminium tape works apparently
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Old 11-23-2020, 11:58 AM   #5
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Default Re: Does power supply have to have metal case?

Quote:
Originally Posted by sam_sam_sam View Post
Is this a computer switching power supply mostly in metal cases ( I do not have an answer for you about this type of switching power supply I do not want to give you the wrong information )

Or is just a switching power supply because this type of switching power supply are mostly made with plastic enclosure
It's general purpose SMPS from china. You know one that is used for LED lights, 3D printers etc.

Quote:
if you dont use radio or give a shit then it will be fine in plastic - they used to sell coloured acrylic shells to customise pc psu's.
How well do those frequencies go through wall? Would it kill neighbours radio/wifi behind concrete wall?

What's the exact frequency? The same frequency as switching?

Aluminium tape sounds good idea.

I dont even have radio at home so I have no idea how to verify if I have enough layers of aluminium foil. And if I put 2 large fans on top then the top of it would leak anyways.
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Old 11-23-2020, 01:54 PM   #6
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Default Re: Does power supply have to have metal case?

switching frequency - something usually between 30KHz and 1MHz + harmonics.
range will be short - 10's of feet, but if you have a radio operator next-door they will be effected because they use long-range ultra-sensitive antenna's
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Old 11-24-2020, 02:33 PM   #7
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Default Re: Does power supply have to have metal case?

Thanks.

For humans it wouldn't do anything? I guess it wouldn't be much stronger than wifi/mobile networks that are already around us?
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Old 11-24-2020, 03:09 PM   #8
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Default Re: Does power supply have to have metal case?

What you hear about RF being injurious to humans is all nonsense by those who don't understand how it works anyway.

It won't do anything to humans unless it gives off an audible whine. Then it'll give you a headache at worst.
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Old 11-26-2020, 01:11 PM   #9
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Default Re: Does power supply have to have metal case?

However, concentrated 1KW RF pointed directly at a person could do something...
Same could be said about connecting 120VAC and passing 8 amperes...

Fear of the unknown. RF, wireless communication, and microwave ovens are voodoo for most people out there and thus is "scary..."
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Old 11-26-2020, 04:03 PM   #10
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Default Re: Does power supply have to have metal case?

MMmmhmm. So ive noticed.

People don't know math. Else they would understand magnitudes.

Thanks broken school system!
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