Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

using pc fan for cooling meanwell in case
using pc fan for cooling meanwell in case
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 27th June 2011, 10:21 AM   #1
Billyo is offline Billyo  Australia
diyAudio Member
Join Date: Apr 2011
Location: Sydney
Default using pc fan for cooling meanwell in case

I want to use a cheap plastic tupperware style enclosure to house my HifimeDIY TK2050 and Meanwell 27 V PSU.

I can drill a few holes for cables and air, but I figure that heat buildup would still be a problem.

Would it be possible to power an ordinary PC fan via the Meanwell? The fan would be at the back of the case and ensure a constant flow of cool air through the holes I would drill.

My back of the envelope calculation using the power and amperage from a random PC fan of P = 1.8W and amps of .15 A suggests (using ohms law) that the effective resistance of the fan is 80 ohms.

If the fan is a 5V fan, then would putting a 350 ohm resistor in series with the fan successfully drop the voltage down to 5V across the fan and successfully run it - or are my calcs or concepts of what a fan needs to run completely wrong and the fan would vaporize?
  Reply With Quote
Old 29th June 2011, 12:47 AM   #2
! is offline !  United States
diyAudio Member
Join Date: Jun 2005
Location: Midwest
I would use a metal case for shielding, but it helps that the PSU has a metal case and the amp board has a ground plane, yes?

Yes you can power an ordinary DC fan, but get one that is at least 24V rated, then current limit it with a resistor down to an acceptably low noise operational RPM.

These figures you have of 1.8W and 0.15A, is this what is on the fan label? Fan labels tend to cite the max momentary current not average, keep in mind that 0.15A at 5V is not 1.8W, it's 0.15*5= 0.75W

I suggest that the power calculation from a random fan is only useful if you are going to use that particular fan. The problem is that it is average power while a fan uses it in pulses, you will probably have voltage spikes well exceeding the capability of the fan's active circuit components. Even when you use a fan rated higher than the peak voltage in a circuit it usually takes experimentation to arrive at the correct resistor value to use for any particular average current or reduction of peak voltage level.

It is possible the fan is a modularized design, to the extent that the voltage sensitive parts inside are designed to handle the highest voltage rated member of that fan family and only the coil and drive current are changed for lower voltage operation, but to be on the safe side I would buy a 24V fan, or at least a 12V fan from a model line that contains a 24V version to address the possibility mentioned above that it "might" have components still operating within their safe zone.

Regardless of what I wrote, you could still try the 5V fan, just don't leave the amp unattended till you figure out if the fan is going to survive, then if it doesn't survive you needed to get a new fan anyway... so then pick one rated for 24V if not 36V (36V DC axial fans almost always have no trouble at 27V input, and "Most" fans rated for 24V can be ran at slightly higher voltage too, they are just spec'd at that as a common voltage that equipment uses so the RPM can be spec'd... but only within a little margin, not 22V difference.
  Reply With Quote


using pc fan for cooling meanwell in caseHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
How to control the cooling fan ... ? TheDealer Power Supplies 7 6th April 2010 06:11 AM
cooling fan controller for chipamp oldfatbubba Chip Amps 16 28th July 2007 06:41 PM
Automatic Cooling Fan hernanstafe Parts 14 17th March 2007 12:41 AM
fan cooling? Raj1 Pass Labs 22 8th January 2003 03:33 PM

New To Site? Need Help?

All times are GMT. The time now is 11:25 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio