AC blower fan rotation direction (1 Viewer)

[PooPipeBoy]

Any other 70 Series owners out there able to confirm?

Looking from the top, mine currently spins anti-clockwise and it doesn't seem right, given that the blades are traveling away from the outlet location. The previous owner opened the motor up at one point and might've reversed the polarity (if that's even possible). There's conflicting information on the internet about how these fans work in basic principle and so it hasn't been of any help.

 

[PooPipeBoy]

Did some more research/experimentation and you can indeed change the rotation direction by swapping the polarity. I pulled the fan apart and it's not possible to swap the wires internally without modification. The fan direction isn't right though so I'm starting to think there's some wires crossed in the dash somewhere.

Can't confirm without facts....c'mon people, help a brother out.

 

[PooPipeBoy]

I gave up on forum help and did a bunch of research to figure this out for myself. Clockwise is the correct rotation direction. Posting this in case anyone else needs this information. The fan uses forward-curved blades as shown by diagram (a) in the picture below. It's counter-intuitive, but this blade orientation has a higher flow rate than if it were to rotate anticlockwise, which is what mine was doing. Swapped the polarity at the electrical connector and it blows much stronger now.

 

[WarDamnEagle]

I agree that none of the fans in that diagram should run counter clockwise given the indicated housing orientation. I think the most typical orientation would be the middle one. Is there any possibility that your impeller was flipped and your fan should run clockwise but with the blades oriented like the middle example? Just curious.

 

[PooPipeBoy]

I agree that none of the fans in that diagram should run counter clockwise given the indicated housing orientation. I think the most typical orientation would be the middle one. Is there any possibility that your impeller was flipped and your fan should run clockwise but with the blades oriented like the middle example? Just curious.

The plastic fan blade molding only goes onto the shaft in one orientation, so it's not possible to flip it. You'd think that reversing the blade direction would reverse the airflow direction but in reality all the configurations blow air in the same direction, just with different characteristics. Forward-curved fans are best for high volume airflow, backward-curved fans are best for high pressure. Different noise levels, different efficiencies etc.