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Scary sparking - need help
grinderman - January 4th, 2015 at 05:45 PM

So I have got my daughters kombi running and registered but it hasn't been driven very far (around the block) and after changing a fuel pump the other night I noticed when giving the 1835 a good rev there seemed to be sparks shooting out of the alternator stand which frightened the crap out of me seeing as a bit of fuel was spilt on engine during the pump changeover.
The alternator is a bosch 55 amp unit that is pretty old but I threw it on the reco motor to replace the old generator. I doubt if I have the wiring wrong because its charging normally, but I wonder, if something was stuffed inside the alternator would it be possible for it to 'shoot current' through the body of the alternator and down the stand?
I had a type 3 fuel pump on it originally to get it running but noticed one night that the alternator and pump body were almost touching and because it was dark I noticed a spark jump across when revving. So I put on a new correct pump and now the sparks seamed to come from where the alternator stand bolts to the engine block. It only happens when you give it a good rev so it seems to be tied with engine speed.
Any advice would be greatly appreciated.
Thanks. Greg


AA003 - January 5th, 2015 at 05:36 AM

Sounds like a bad earth on the alternator.


psimitar - January 5th, 2015 at 07:28 PM

Really the only slight arcing you should get is from the brushes on the spinning commutator inside the alternator. Earthing the alternator just means the arcing will continue inside the alternator case.
Now as you've tried a few different alternators then I'm wondering if these are externally regulated alternators?


grinderman - January 5th, 2015 at 09:47 PM

When I used this alternator last on my dual cab it had 2 wires that go to a Bosch re51 regulator and it is set up the same now in this motor. So I might check the earth and try again.


Aussie Dubbin - January 5th, 2015 at 11:32 PM

What condition are the bushes in? But shouldn't cause that either.


AA003 - January 6th, 2015 at 06:39 AM

Quote:
Originally posted by grinderman
[size=4]sparks shooting out of the alternator stand [/size]



Quote:
Originally posted by grinderman [size=4]sparks seamed to come from where the alternator stand bolts to the engine block.[/size]


That isn't brushes.


psimitar - January 6th, 2015 at 10:01 PM

Having voltage spark like that means that the voltage and or/current being generated is far bigger than it should be as this would explain how the sparks can jump so far. So try a different regulator. No scratch that as, if memory serves, the alternator must be matched to it's regulator due to differing way manufacturers design the way the voltages etc are created.