Alternator: Testing and Inspection

Generator

INSPECTION

1. DIODE (2.5 L MODEL)

CAUTION: There is the possibility of damaging the diodes if a mega-tester (used to measure high voltages) or a similar measuring instrument is used. Never use a mega tester or equivalent for this test.

1. Check for continuity between the diode lead and positive side heat sink. If resistance is 1 Ohm or more only in the direction from the diode lead to the heat sink, replace the rectifier.






2. Check for continuity between the negative side heat sink and diode lead. If resistance is 1 Ohm or more only in the direction from the heat sink to the diode lead, replace the rectifier.






2. STATOR COIL (2.5 L MODEL)

1. Inspect continuity between the stator coil lead wire terminals. If the resistance is 1 Ohm or more, replace the stator assembly.






2. Inspect the continuity between the stator coil stator core and lead wire terminals. If the resistance is 1 Ohm or less, replace the stator assembly.






3. ROTOR
1. Inspect the slip rings for contamination or any roughness on the sliding surface. Repair the slip ring surface using a lathe or sand paper.
2. Measure the slip ring outer diameter. Replace the rotor assembly if the slip ring is worn.

Slip ring outer diameter:
Standard 22.7 mm (0.894 in)
Limit 22.1 mm (0.870 in)

3. Using a circuit tester, check the resistance between slip rings. If the resistance is not within the standard, replace the rotor assembly.

Standard: Approx. 1.8 - 2.2 Ohm






4. Check the continuity between slip ring and rotor core or shaft. If the resistance is 1 O or less, replace the rotor assembly.






5. Check the rear ball bearing. If there is any noise, or the rotor does not rotate smoothly, replace the bearings.

4. BRUSH

1. Measure the length of each brush. Replace the brush if wear exceeds service limits. There is a service limit mark (A) on each brush.

Brush length:
- 2.5 L model
Standard (1) 18.5 mm (0.728 in)
Limit (2) 5.0 mm (0.197 in)






2. Using a spring pressure indicator, push the brush into the brush holder until its tip protrudes 2 mm (0.08 in). Then measure the pressure of brush spring. If the pressure is 2.648 N (270 g, 9.52 oz) or less, replace the brush spring with a new part. 4.609 - 5.786 N (470 - 590 g, 16.58 - 20.810 oz) pressure is required on the new spring.






5. BALL BEARING (FRONT SIDE)
Check the front ball bearings. Replace the ball bearings if there is resistance in the rotation, or if there is any abnormal noise.

6. OTHER INSPECTIONS
Check that the generator does not have deformation, cracks and any other damage.