Charging System - Generators & Regulators: Generator: Inspection

1. Using an ohmmeter, check the continuity between terminals F and B.
   1. Standard: 
   2. 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 regulator.

   Fig 1: Checking Voltage Regulator Continuity (F To B)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Using an ohmmeter, check the continuity between terminals F and E.
   1. Standard: 
   2. 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 regulator.

   Fig 2: Checking Voltage Regulator Continuity (E To F))

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Check the rotor for open circuit.

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

   1. Standard resistance: 2.1 - 2.5 ° at 20°C (68°F) 

   If there is no continuity, replace the rotor.

   Fig 3: Checking Rotor For Open Circuit

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

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

   If there is continuity, replace the rotor.

   Fig 4: Checking Rotor For Ground

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Check that the slip rings are not rough or scored.

   If rough or scored, replace the rotor.

4. Using a vernier caliper, 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: Measuring Slip Ring Diameter

   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: Mesuring Brush Length Using Vernier

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: Checking Positive Rectifier

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Check the negative (-) rectifire.
   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.

      Fig 10: Checking Negative Rectifier

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Check the bearing is not rough or worn.

If necessary, replace the bearing. See  1 under REPLACEMENT.