ALTERNATORS

I learn't that the rotor is the electro magnet that takes power from the stator and the rectifier controls where the power goes. Also we measured the brushes and the minimum brush length 4.0mm to be in good working order .We also connected a power box tester  to the alternators regulator to test for a short circuit , if the short circuit light on the power box shines bright their is a short circuit . if the light blinks it should be ok .I also did a test on the rectifier to test for negative diodes .by using a multimeter on the ohms scale then put the common lead to the E terminal of the rectifier and the red lead to the p terminal on the rectifier the resistance should be low .and when puting the red lead on the E terminal of the rectifier and the common lead to the p terminal their should not be a voltage drop higher than 0.5-0.7 for it to be in good working order .
In a rotor winding ground test it should show infinite on the ohms scale of the multimeter .and on a internal rotor winding resistance test it should show between 2-6 ohms on the multimeter for it to be in good condition .Also the job of the alternator is to keep the battery fully charged and run  the accessories of the car e.g. lights ,stereos,electric fans, airconditioning  and the ecu .