PDA

View Full Version : motor cooling?



kiwi8
05-04-2007, 08:27 AM
Hi guys I just got a fan to help cool the motor/inside of car. The fan is mounted above the motor. Should the fan be extracting the hot air or blowing cool air down. I'm trying to take into account the air flow thru the body in general.
Cheers.

SteveR1960
05-04-2007, 11:15 AM
Blowing down onto the motor. Will expalin this in regards to 1) volume of air flow and 2) maximum cooling potential.

1) If there is a restriction to flow on the upper side it will have the same impact on the volume of air displaced at a given rpm no matter which way you orient the fan. So for this point fan direction does not matter.

2) Cooling as you know is most effective if air contacts the hot spots - The problem with reverse flow - sucking frpm the motor side and expelling up away from the motor is that air will pass through the motor that did not glide by the motor. VBut when forcing air down on the motor you guarantee the maximum amount contacts it. Also note, this is th eonly way to get significant air to hit the heatsink fins. In reverse flow mode the fins are a baffle that creates dead zones and prevents flow against them.

Of course to guarantee the most cool air flow, a hole in the body near the fan intake - but in front of it so moving air is forced towards it will help also.

I think you understand this experientially with home cooling or desk top fans. Blowing air on you feels better than standing on the back side. Note - this is different than cooling a sealed compartment as a whole vs. a localized spot.

kiwi8
05-05-2007, 04:16 AM
cheers SteveR a really informative and clear answer.

SteveR1960
05-05-2007, 05:12 AM
Keep up the fun modding of your machine!