Alternator: Testing and Inspection: Diagnosis and Testing

Mount alternator securely in a suitable test stand prior to testing. Ensure test stand battery is fully charged before conducting any alternator tests.

Fig. 9 Circuit For Testing Alternator Voltage & Current Output:

1. Make appropriate test connections shown in Fig. 9, to test alternator output speed.
2. Open switch SW1 and close switch SW2, then operate alternator test stand.
3. Slowly increase alternator speed while observing alternator output voltage.
4. Output should be 13.5 volts at 900 RPM.
5. Continue raising alternator speed while observing voltmeter. Voltage should remain within 5000 RPM for Legacy, or 5000 RPM for Loyale.
6. Check current output with test connections as shown in Fig. 9. Close switches 1 and 2, then set variable resistor at minimum value.
7. Increase alternator speed, using variable resistor to maintain voltage at 13.5 volts. Current ratings should be as follows:
a. On Legacy models, readings should be at least 33 amps at 1500 RPM; 66 amps at 3000 RPM; and 80 amps at 6000 RPM.