[Amps] Forced-air cooling system measurements

[Ron Youvan]

Scott Townley wrote:

> The general recommendation for checking forced-air cooling system
> performance is to use a manometer to check back pressure.
> I wonder, isn't the "true" test the CFM in the exhaust?  After all, if the
> blower can't "push" through the tube/socket back pressure, then the net
> result is not enough CFM.
> I ask that because while I don't have a manometer (though that is not
> insurmountable by any means), I do have an anemometer calibrated to read
> CFM.  It would seem that a guaranteed test is to be able to measure the
> recommended CFM in the exhaust air, if the exhaust is sufficiently ducted.
> Thoughts?

   What you say is true, but the airflow across the heat sink of the heat source with a manometer is 
the established way to measure the cooling air flow.  Using the manometer requires proper ducting 
and sealing to get a reading and this insures none of the air flow bypasses the load's heat sink.
Having NN CFM of air flow doesn't assure all of the air went through the load's heat sink.
-- 
    Ron  KA4INM - rule of thumb:
                  If it's winders it needs rebooted weekly and will always benefit from more memory!