Hyper 212 Evo fan spinning in both directions

[RustedPencils]

So my Hyper 212 Evo fan seems to be acting strange (Not sure if it has always done this in the past year, new case w/ window a few days ago), it will spin regularly pushing air to the back of the case. However, at times it will slow down and begin to spin the opposite direction for a minute or two, and then begin to spin the correct direction again and repeat in a non consecutive pattern. My heat sink still feels cool after a load of gaming, but not 100% sure if this would bring up and issue or not, just bugs me when looking at it when it happens. Any suggestions? Thanks!

 

[KKAW]

Hmm ok... there is no way that it is "changing" the direction of the wind it may be that you are feeling it when it is on higher RPM you may feel it pushing a bit on the other side.

If you are 100% sure that you are not mistaken you should deattach the fans and test the fan outside the case and reattach it properly!

 

[synphul]

I think what you're seeing is an optical illusion. It's not truly spinning 2 different directions, when a fan is spinning at a fixed speed then slows due to lower cooling needs and fan speed control it will have a moment of what appears to be hesitation and look like it's lazily spinning backwards. It's not. Rims on cars can have the same visual effect, if you're ever riding passenger (don't recommend while driving) watch the rims of the cars around you going from say 35mph to a stop at a red light. At some point when the vehicle is slowing down, the rims/wheels will have a moment where they appear to be rotating slowly backwards which obviously isn't the case or it would as if it slammed in reverse.

In order for a fan to be spinning one direction, then another it would have to slow all the way down to a dead stop and then go the other way. They can't shift directions on the fly or there would be a heck of a shudder and/or the spindle would snap.

https://en.wikipedia.org/wiki/Wagon-wheel_effect

 

[RustedPencils]

I think what you're seeing is an optical illusion. It's not truly spinning 2 different directions, when a fan is spinning at a fixed speed then slows due to lower cooling needs and fan speed control it will have a moment of what appears to be hesitation and look like it's lazily spinning backwards. It's not. Rims on cars can have the same visual effect, if you're ever riding passenger (don't recommend while driving) watch the rims of the cars around you going from say 35mph to a stop at a red light. At some point when the vehicle is slowing down, the rims/wheels will have a moment where they appear to be rotating slowly backwards which obviously isn't the case or it would as if it slammed in reverse.

In order for a fan to be spinning one direction, then another it would have to slow all the way down to a dead stop and then go the other way. They can't shift directions on the fly or there would be a heck of a shudder and/or the spindle would snap.

https://en.wikipedia.org/wiki/Wagon-wheel_effect

Haha i'm not retarded, it's actually slowing down to a stop and changing direction and pick up speed again as if nothing was wrong, and then repeat. Begin spinning left, goes to a stop, spins right, goes to a stop, repeat etc.

 

[Puff3r]

This feature is used to help prevent dust build up on the fans. It is becoming more common and is actually from your motherboard not the cooler. It reverses the polarity of the fans generally once ever 30 minutes to an hour. With my board I can control which fan headers this applies to and how often it occurs. Nice feature.

 

[RustedPencils]

This feature is used to help prevent dust build up on the fans. It is becoming more common and is actually from your motherboard not the cooler. It reverses the polarity of the fans generally once ever 30 minutes to an hour. With my board I can control which fan headers this applies to and how often it occurs. Nice feature.

That seems to be the case and most reasonable, I just never noticed it until lately and wasn't sure about it. I was actually tempted to get a new motherboard because of it. Thanks for the response