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Old 02-28-2012, 07:00 PM
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Originally Posted by russ69coupe

I probably am just over thinking this, but at the price of these things I don't want to kill any.
Just wanted to make sure that rotating it in the opposite direction (if this setup requires it) wouldn't fry the electronics in it. The cooling fan on it I can deal with I think. If not I'll be going to plan B. Once I can find out what that would be that is.

Electrically, the alternator works the same regardless of direction of rotation.

As said, the fan function is the only real concern. The alternator cooling fan is designed to pull air into the back of the alternator to cool the diodes/heat sink located there. Then the air is exhausted out the front. Spinning the fan backwards will pull air (less efficiently) in the front and push it back through the alternator until it reaches the diodes/heat sink then exhausts out the back. So IF the fan is directional, it will be more efficient in one direction than the other.

Whether or not the loss of the fan's efficiency is a matter for concern will depend on how hard the alternator is worked, and things like the underhood temperature and air flow around the alternator in the vehicle it's in now.

My gut feeling is there will not be an issue unless there are higher than normal temps under hood and/or the alternator duty cycle is extreme. But if this were to be a concern, the fan can be swapped for one that gives the correct air flow or one that's "bidirectional" can be used instead. A bi-fan will have basically straight blades radiating out and won't have any fan blade bias as to direction like a directional fan has.
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