Alternator question

Drew · Nov 11, 2019

Does an alternator care which way it turns to charge? Real estate is at a premium where I am trying put an alternator and if I can flip it around backwards I think I have enough room to make it work.

Mike M · Nov 11, 2019

From what I remember it does not matter which way an alt. turns.

old · Nov 11, 2019

Only way I could see how rotation would matter is if the brushes where set up for only one way and they would sit at an angle which I have never seen in an alternator so no it should now matter.

On a generator that is what polarizing does

buickanddeere · Nov 11, 2019

Should swap the cooling fan for the opposite rotation .

Bob · Nov 11, 2019

(quoted from post at 14:01:03 11/11/19) Does an alternator care which way it turns to charge? Real estate is at a premium where I am trying put an alternator and if I can flip it around backwards I think I have enough room to make it work.

I believe it's been done on some Detroits and likely other engines.

Many alternators do NOT use a key in the pulley, nor have a keyway in the shaft or pulley. The direction of the torque on the pulley tends to tighten the nut.

Driving one of those backwards might eventually cause the pulley and nut to slip a bit, eventually coming loose.

I would find and use an alternator with a keyed pulley, or, at the least lock the pulley and nut in place with medium strength Loctite.

One other thing, if re-using an alternator with some hours on it, the brushes will be worn on the side of the brush holder that they are drug against by the rotation of the sliprings, and worn at an angle at the slipring contact area.

It would be a good idea to install new brushes so they start out contacting the sliprings "square" in the new direction of rotation.

Mike(NEOhio) · Nov 11, 2019

Only matters for the cooling fan. Output is created in the stator and is actually AC so the same current will come off the rectifiers.

David G · Nov 11, 2019

As stated, only for the fan.

Drew · Nov 12, 2019

I appreciate all the replies! I've found a couple different alternators on Amazon that I think I can make work. Now I've just got to get the end of a fanshaft mapped out and get a drive system and bracket engineered.

Bob, I never thought about reverse rotation backing the nut/pulley off, but will add a couple of drops of Loctite.

Alternator question

Drew

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Mike M

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old

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buickanddeere

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Bob

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Mike(NEOhio)

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David G

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Drew

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