1 Topic by Staffordknot (edited by Staffordknot 2013-06-08 20:36:43)

  • Staffordknot
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Topic: Which is best place to pick up 12v supply for a cooling fan to board

Hi I was wondering where was the best place to pick up a 12v supply to power a fan to cool the electronics?

I know I can just pick up straight of the main feed in and my fan would be powered all the time which is fine. But is this safe to do so? My power supply is 47amp so shouldn't I use a fuse or something as I'm pretty sure 47amps is more then enough to melt the wiring to the fan?

Or do I just not worry about it lol?

2 Reply by satman49

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Re: Which is best place to pick up 12v supply for a cooling fan to board

I'm cheap  lol . I am using  a  Holmes Personal Air Purifier behind the board, dual purpose, helps keep the dust down and blows cool air on the board . 14.94 at "wallyworld"

SD3, E3D hotend,linear bearing on x/y axis',pillow block bearing on y conneting rod, ball bearngs on front y axis, fan on y stepper motor.

3 Reply by lawsy

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Re: Which is best place to pick up 12v supply for a cooling fan to board

The 47 amp rating on the power supply is a potential amount it can deliver. The amount that it delivers is based on what components are connected, it won't give 47 amps every time. Connecting just an LED will draw milliamps.

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4 Reply by adrian

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Re: Which is best place to pick up 12v supply for a cooling fan to board

Voltage is Supplied, Current is drawn.

What this means is that you will Supply what the indicated and rated voltage is; so 12v will spit out 12v.

You will draw, or use what is required, of Current. So a 1000amp PSU can supply as 100ma fan. As long as the voltage matches...

There is limitations in my above statement, but for general electronics, it holds true.

5 Reply by Staffordknot

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Re: Which is best place to pick up 12v supply for a cooling fan to board

I thought a fuse is to protect in a fault situation and usually to protect the wiring not the device. The fuse should blow in a short circuit before the wire to a device melts. If my fan was to develope a fault or wire come loose and short on a 47 amp supply won't the wiringing melt / potentially cause a fire?

6 Reply by Hunter Green (edited by Hunter Green 2013-06-09 12:53:21)

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Re: Which is best place to pick up 12v supply for a cooling fan to board

I did it just the way you describe.  I bought one of these:
http://www.amazon.com/gp/product/B00452 … &psc=1

Then I simply snipped off the end and attached it to the fan power leads.
http://www.thingiverse.com/make:37220

http://thingiverse-production.s3.amazonaws.com/renders/cd/7b/36/f1/53/971969_657564577591224_499243330_n_preview_featured.jpg

Then I plug it into the same power strip as the SD3 so it comes on when I plug that in, and stays on.  Here it is installed:

http://thingiverse-production.s3.amazonaws.com/renders/6b/fb/79/95/ca/376777_657635897584092_1652330888_n_preview_featured.jpg

I didn't want to use the leads on the board because people suggested I should save that for other mods that were more important to be drawn from there, plus this was much easier for me given the limits on my electronics abilities.

FlashForge Creator, SketchUp 2013