I just bought a "refurbished" alternator and while visually inspecting it noticed that some of the stator wires had spots of missing insulation:

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The stator body and parts of it's wiring have been spray painted black, and you can clearly see bare wire where the insulation and paint have come off.

This seems to me like a potential problem, and I'm thinking I should probably just return the alternator without even installing it ( it has a six month warranty ).

What specific problems might this missing insulation cause, and am I correct in thinking I should not accept this alternator and ask for a different one?

  • Looks like a cheap rebuild job. – Moab Aug 9 '16 at 21:53
  • @Moab That's why I said "refurbished". They basically just take junkyard alternators, open them up to see if there is anything obviously wrong like a burnt up stator or bad bearings, clean and spray paint the stator and slap a six month warranty on it. Their test bench isn't capable of testing ECU controlled alternators, so the test is if it works when I install it they said. I just don't want to bother installing it if there is already something "obviously" wrong with it. – Robert S. Barnes Aug 10 '16 at 5:31

That does not look good, especially as a recently rebuilt alternator.

The insulation on the stator keeps the stator from shorting out internally and also prevents the windings from shorting against the case. I would also be concerned that the exposed windings might develop a high resistance (high as in "not likely to start smoking") short to ground or between phases on the alternator as a result of moisture and atmospheric contamination. A short like that will cause heating and will diminish the alternator output.

I think you would be wise to return it.

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  • I went to return it and the guy tried to argue with me that it's not a big deal, what do I care since it has a six month warranty, that even if I touch the insulation and the B+ post I'll still see continuity ( BS ) but in the end he said leave that one and come back tomorrow and he'll give me a different one without any bare spots on the wires. Really kind of sucks that this is only place in the city I can find which "refurbishes" alternators. – Robert S. Barnes Aug 10 '16 at 9:06
  • Not confidence inspiring... In the US,at least, auto parts stores will often be able to get refurbished alternators. A 6-month warranty actually seems kind of short and you care because of the hassle of removing the old one and installing the replacement. Far better to do what you're doing and try your best to get a good one. – dlu Aug 10 '16 at 12:07

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