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Alternator - Run In Reverse?
smart1275gt - 10/12/07 at 12:51 PM

I may need to reposition my alternator around another way which means it will rotate in reverse. Will it be ok and still charge?


nitram38 - 10/12/07 at 12:57 PM

I don't think it matters.
Your alternator produces AC which is converted to DC by a bridge rectifier.
It will produce AC in whatever direction it turns


Mr Whippy - 10/12/07 at 01:02 PM

never tried it but agree it should work. I think the cooling fan might not work so well. Tell us if it explodes


matt_claydon - 10/12/07 at 01:07 PM

Wouldn't worry about the fan, our cars have so little drain on the alternator it shouldn't really get hot. I removed the fan on mine for clearance and have never had any trouble.


tegwin - 10/12/07 at 01:46 PM

If the alternator has an internal rectifier/regulator then you may have trouble!!!


nitram38 - 10/12/07 at 01:53 PM

quote:
Originally posted by tegwin
If the alternator has an internal rectifier/regulator then you may have trouble!!!


Why?


BenB - 10/12/07 at 04:02 PM

Alternators don't complain if run backwards unless they're marginal on cooling. The fan will not work very well backwards.


rsk289locost - 10/12/07 at 08:12 PM

Hi. The Jag V12 alternator was mounted ahead of the engine facing rearwards. Don't know if it that helps?? May be some info on the Jag web sites.


dave r - 10/12/07 at 09:08 PM

if your worried, take the original fan off, and mount a small 12 pc fan at the back near the regulator... wont make any difference (95% of the time it will be in a 50mph ++ wind) but might make you feel better ;p


smart1275gt - 10/12/07 at 09:17 PM

Cheers, I'll get the multimeter out and try spinning it either way.

ps, nice avatar Dave R!!


t.j. - 10/12/07 at 09:29 PM

If there is a only one-way-pully (modern cars) this wouldn't work.


02GF74 - 13/12/07 at 09:32 AM

I've seen this question been asked before, can't remember where.

consensus was it should be ok but depends on model - some alternators may have brushes that will work one way round, I can't imagine how you can design one to be like that since there is alwy as the possibility of the engine running backwards to a bit e.g. when turning over by hand or backfire perhaps.

I reckon you will be ok. Is it a lucas a127 type?

fyi - read somewhere the the fans suck air fromthe back and ouot ofthe front.

you may be able to bend up some steel to make your own fan if you are very careful as it needs to be balanced.


MikeRJ - 13/12/07 at 09:53 AM

One possible issue if the pulley is held on by a nut whose thread will be handed to tighten with normal rotation, rather than loosen...