Digital fan tester..

Thread Starter

thinkerbelle

Joined May 19, 2015
11
I am currently working on my final year project:building a digital fan tester system for a Sunon brushless dc fan that will be used without necessary taking the fan out...I plan to incorporate use of LCD & pic microcontroller.
Kindly advise on how to go about this?and advise on how to program/interface LCD with microcontroller.
 

MaxHeadRoom

Joined Jul 18, 2013
28,617
I cannot quite see how you are going to accomplish this when the BLDC controller is embedded in the fan itself.
There is maybe current and the validity of the fail sense, but what other details else where you hoping to obtain?
Max.
 

wayneh

Joined Sep 9, 2010
17,496
Fans move air. If the blades are not damaged, rpm will give a proxy measure of fan performance. But I don't see an rpm meter as much of a final year project.
 

Thread Starter

thinkerbelle

Joined May 19, 2015
11
I cannot quite see how you are going to accomplish this when the BLDC controller is embedded in the fan itself.
There is maybe current and the validity of the fail sense, but what other details else where you hoping to obtain?
Max.
Thanks Max really appreciate your feedback...how would you have rather gone about this?
 

Thread Starter

thinkerbelle

Joined May 19, 2015
11
Fans move air. If the blades are not damaged, rpm will give a proxy measure of fan performance. But I don't see an rpm meter as much of a final year project.
Thank you wayneh,
Yes it seems like a very easy project for final year :)...but there is a special reason why I am undertaking it.
 

DickCappels

Joined Aug 21, 2008
10,153
Just test for what fans are supposed to do:

Air pressure in a fixture or flow in CFM (cubic feet per minute) possibly taking temperature into account.
 

MaxHeadRoom

Joined Jul 18, 2013
28,617
Basically how to detect whether the fan is running about its correct speed.
You would need to know either what the rated rpm is at the CFM figure for the fan or at least the normal rpm figure, the latter could be done with a retro-reflective tach style sensor to read the rpm.
Max.
 

Thread Starter

thinkerbelle

Joined May 19, 2015
11
You would need to know either what the rated rpm is at the CFM figure for the fan or at least the normal rpm figure, the latter could be done with a retro-reflective tach style sensor to read the rpm.
Max.
Was wondering if I can monitor the square wave coming from the fan by a microcontroller input....then build in the sofware detection loop for this?
 

alfacliff

Joined Dec 13, 2013
2,458
if you change to the other type of fan, the one with three leads, the third lead is a temprature sensor, that would give you the most important information, whether the fan was cooling or not.
 

AnalogKid

Joined Aug 1, 2013
10,986
If you are testing a fan that is installed in equipment, you can put a white dot sticker on the hub and use an optical tachometer to determine the speed.
You can use an acoustic microphone to pickup the frequency of the fan blades against the fan motor struts, and divide that by the number of blades to get the speed.
You can use an inductive sensor like a coil of wire on a ferrite rod to pickup the switched magnetic fields, and divide that by 2 or 4 to get the speed.
If this is on a test bench, you can insert a small current shunt resistor in series with the ground lead of the fan, look at the voltage across the resistor, and divide that by 2 or 4 to get the speed.
You can place a hall effect sensor near the motor hub to sense the magnetic fields, and divide that by 2 or 4 to get the speed.

ak
 
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