Alternator: Testing and Inspection

WAVEFORM CHECK USING AN ANALYZER




MEASUREMENT METHOD
Connect the analyzer special patterns pick-up to the generator B terminal.

STANDARD WAVEFORM

Observation Conditions:

Observation Conditions






NOTE: The voltage waveform of the generator B terminal can undulate as shown at left. This waveform is produced when the regulator operates according to fluctuations in the generator load (current), and is normal for the generator.

In addition, if the ripples are abnormally high (more than approximately 2 V when the engine is idling), the cause is probably an open circuit between the generator B terminal and the battery due to a blown fuse, and the generator itself is usually okay.

ABNORMAL WAVEFORMS EXAMPLES






NOTE:
1. The size of the waveform patterns differs largely, depending on the adjustment of the analyzer's variable knob.
2. Identification of abnormal waveforms is easiest with a large output current (regulator not operating). These waveforms can be observed when the headlights are on.
3. Check the condition of the charging warning light (illuminated/not illuminated). Also, check the condition of all charging system components.