Re: Generator polarity??

Posted by Ross On 2012/4/19 5:17:54

Sounds like the beast isn't charging at all--that's why the more you drive the sooner its dead. Put a voltmeter across the battery terminals and you should get 6.8 to 7.2 volts at high idle.

Generators do need to be polarized when anything is changed. If your car is negative ground and you want to keep it that way, then take a jumper lead from the positive post of the battery and touch it briefly to the armature post on the generator (the one with the thicker wire).

If that's the real problem, you should now be good to go as the electrons will now march in the right direction when the engine is running.

If still no charge, look very carefully at what is stamped on the flanges of your voltage regulator. If it says 6 pos or 6P you will need to run positive ground or it will not be happy if it isn't ruined already.

Here's the easiest test in the world to see if the generator itself is OK: Take off the fanbelt. With one jumper ground the field terminal (small wire)to anything convenient. With another jumper now apply battery to the armature terminal. The generator should now run smoothly as an electric motor. If it won't then it needs to be serviced.