Hook up Alternator to battery and it sparks

[LaN-]

so here is "the deal"

i hook up the wires to the battery that run to the alternator and it sparks like crazy. SO i thought it was a short but when i check the resistance of the cables on the alternator its 0 ohms so thats fine.

what exactly does the alternator ground itself out to? and wtf is goin on here

any ideas?

 

[wolf20043]

I would double check the ground wire ands make sure the nut that holds it on is not backing off.
Mike

 

[GTM]

so here is "the deal"

i hook up the wires to the battery that run to the alternator and it sparks like crazy. SO i thought it was a short but when i check the resistance of the cables on the alternator its 0 ohms so thats fine.

what exactly does the alternator ground itself out to? and wtf is goin on here

any ideas?

Disconnect the B+ from the alternator and then attach all the battery cables correctly, there should be nominal sparking with everything turned off. Attach the B+ wire, if this "sparks like crazy" then you have a problem with the alternator. You may find the insulator is damaged where the B+ stud passes through the rear of the alternator case. If no damage is seen and the stud is tight then you have an internal problem which still could involve a short of the wires on the stud or you have a shorted diode and will have to be replaced.

The diodes will usually have around 600 and 700 (+/- 100) ohms each depending on the polarity. If you are not skilled enough or cannot find the diodes then the Alternator will have to be rebuilt or replaced.

The brushes, slip rings and rotor will never have a significant short as you describe.

Cheers,
GTM

 

[LaN-]

thanks man i'll keep you guys posted

 

[eclipsalon]

Decided to bring this thread back because its unresolved and i have "LaN"'s same problem.
Everything was working fine before i disconected it and all i did was replace the oe wires with a 4ga.
Did the alt short out some how?

 

[stormy69]

are you also showing "0" ohms?

 

[95TalonOwner]

Double check all your connections. If it worked before you did anything, you most likely hooked it back up wrong.

 

[eclipsalon]

Its all the same, even put the old wire back on to check it out and same. Thats the bolt that should be holding the wire correct?

are you also showing "0" ohms?

Cant find my mulimeter, but what should the alt be reading?

 

[eclipsalon]

looks like GTM was right on the money. New alternor, problem solved.