Alternator: Testing and Inspection

Rotor Inspection





1. Wiring damage
1. Check the resistance between the slip rings with an ohmmeter.
Specification
3.5-4.5 Ohms [20° C{68° F]}
2. If not within the specification, replace the rotor.





2. Ground of field coil
1. Check for no continuity between each slip ring and the core with an ohmmeter.
2. Replace the rotor if there is continuity.

3. Slip ring surface
^ If the slip ring surface is rough, use fine sandpaper to repair it.

Stator Inspection





1. Wiring damage
1. Check for continuity between the stator coil leads with an ohmmeter.
2. Replace the stator if there is no continuity.





2. Ground of stator coil
1. Check for no continuity between the stator coil leads and the core with an ohmmeter.
2. Replace the stator if there is continuity.

Brush Inspection

^ If any brush is worn almost to or beyond the wear limit, replace all the brushes.





Standard
21.5 mm { 0.846 in }
Minimum
8.0 mm (0.32 in)

Brush Spring Inspection

1. Measure the force of the brush spring with a spring pressure gauge.
2. Replace the spring if necessary.

Standard force
3.2-4.3 N { 0.32-0.44 kgf , 0.71-0.96 lbf }

Minimum
1.6-2.3 N { 0.16-0.24 kgf 0.36-0.52 lbf }





NOTE: Read the spring pressure gauge at a brush tip projection of 2 mm (0.079 in }.

Rectifier Inspection








1. Check for continuity of the diodes with an ohmmeter.





2. Replace the rectifier if necessary.