What is an alternator ripple?
Then, what is acceptable alternator ripple?
A multimeter can read AC voltage and can be used to test for ripple. The alternator should be replaced if AC voltage of more than 50mV is detected (in some cars as much as 100mV is acceptable). If there is more than 0.1 volt (50-100mV, depending on the vehicle) of AC ripple, then the alternator is most likely bad.
One may also ask, what does excessive ripple in charging system mean? There are electronic components inside the alternator called diodes that are responsible for keeping the ripple as small as possible. If one or more diode fails the ripple becomes excessive. This can cause charging issues or stress other electronic components in the vehicle.
Likewise, what causes excessive ripple in an alternator?
Excessive ripple may mean that one winding of the alternator is open or that a rectifier has gone bad. In any event, if the diagnosis is correct, you're probably looking at a new alternator.
What is AC ripple test?
Alternator AC ripple – without ECM control. The purpose of this test is to check the rectification of the alternator output voltage, where the alternator output is not regulated by the Engine Control Module (ECM).