Charging Systems: Generator: Inspection

1. Using an ohmmeter, check the continuity between terminals F and B.
   1. Standard  : When the positive and negative poles between terminals F and B are exchanged, there is continuity in one way but no continuity in another way.

   If the continuity is not as specified, replace the voltage regulator.

   Fig 1: Checking Continuity Between F & B

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Using an ohmmeter, check the continuity between terminals F and E.
   1. Standard  : When the positive and negative poles between terminals F and E are exchanged, there is continuity in one way but no continuity in another way.

   If the continuity is not as specified, replace the voltage regulator.

   Fig 2: Checking Continuity Between F & E

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Check rotor for open circuit.

   Using an ohmmeter, check that there is continuity between the slip rings.

   1. Standard Resistance  : 2.2-2.4 ohms at 20°C (68°F)
      Fig 3: Checking Rotor For Open Circuit

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   If there is no continuity, replace the rotor.

2. Check the rotor for ground.

   Using an ohmmeter, check that there is no continuity between the slip ring and rotor.

   Fig 4: Checking Rotor For Ground

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   If there is continuity, replace the rotor.

3. Check that the slip rings are not rough or scored.

   If rough or scored, replace the rotor.

4. Using vernier calipers, measure the slip ring diameter.
   1. Standard Diameter  : 14.2-14.4 mm (0.559-0.567 in.)
   2. Minimum Diameter  : 12.8 mm (0.504 in.)

   If the diameter is less than minimum, replace the rotor.

   Fig 5: Checking Slip Rings

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Check the stator for open circuit.

   Using an ohmmeter, check that there is continuity between the coil leads.

   If there is no continuity, replace the drive end frame assembly.

   Fig 6: Checking Stator For Open Circuit

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Check the stator for ground.

   Using an ohmmeter, check that there is no continuity between the coil lead and drive end frame.

   If there is continuity, replace the drive end frame assembly.

   Fig 7: Checking Stator For Ground

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Using vernier calipers, measure the exposed brush length.

1. Standard Exposed Length  : 9.5-11.5 mm (0.374-0.453 in.)
2. Minimum Exposed Length  : 1.5 mm (0.059 in.)

If the exposed length is less than minimum, replace the brush holder assembly.

Fig 8: Measuring Exposed Brush Length

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Check the positive (+) rectifier.
   1. Using an ohmmeter, connect one tester probe to the positive (+) terminal and the other to each rectifier terminal.
   2. Reverse the polarity of the tester probes and repeat step (a).
   3. Check that one shows continuity and the other shows no continuity.

      If continuity is not as specified, replace the rectifier holder.

      Fig 9: Identifying Positive Rectifier Terminals

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Check the negative (-) rectifier.
   1. Using an ohmmeter, connect one tester probe to each negative (-) terminal and the other to each rectifier terminal.
   2. Reverse the polarity of the tester probes and repeat step (a).
   3. Check that one shows continuity and the other shows no continuity.

      If continuity is not as specified, replace the rectifier holder.

Check the bearing is not rough or worn.

If necessary, replace the bearing. See REPLACEMENT .

Fig 10: Identifying Negative Rectifier Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002