Hi, my 3d printer psu fan gave up the ghost, and I wanted to replace it. It was pretty noisy, so I thought about upgrading from a 30mm to an 80mm fan. I am designing the top case with mounting holes, and want some input on where to place the new fan. The original placement is the box with the red color. The green and blue box are some options I thought of for the new fan placement. Would placing it over the busier part of the pcb yield lower temps, or is that a bad idea? Does placement even matter for psu fans?
The new fan has higher airflow, but lower static pressure than the original one, and the plan is for it to always spin at a low rpm and occasionally speed up when the psu detects a high temperature.
The original config runs it completely fanless until the psu reaches 50c and only then does it send voltage to the fan header.
It looks like you would want an even airflow through the whole PSU. The main heat-generating components are using the sides of the housing as a heat sink. I’m guessing the fan is mostly so the air inside the housing doesn’t get too warm, not to cool individual components.
Where is the original air exhaust? If it’s near the bottom of the picture, that would confirm my theory. In that case, I would keep the fan placement as close to original as possible (i.e. the blue square).
The original exhaust was at the bottom roughly where the green square is. Since the psu is mounted vertically and I’m designing a new top plate I was thinking it might be a good idea to mount the fan at the bottom so the it could be using convection to its advantage.
Here’s how the exact model psu looks like
Are you 3D printing a new top plate for the psu? Remember that the steel housing also functions to contain the emi generated from the psu components. You could end up increasing electrical noise for other components if your new top plate isn’t conductive and grounded.
I didn’t think of that. Thanks for pointing that out! I guess I can cover the inside in aluminium foil tape to stop the electrical noise
That’s probably not a bad idea, although I doubt it will make much of a difference. But since you’re redesigning the whole thing, might as well do it.