Charging System - Generators & Regulators: Generator: Inspection

1. Using an ohmmeter, check the continuity between terminals F and B.
   Fig 1: Using Ohmmeter To Inspect Voltage Regulator (1 Of 2)
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. Standard: When the positive and negative poles between terminals F and B are exchanged, there is continuity in one direction, but not the other. 

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

2. Using an ohmmeter, check the continuity between terminals F and E.
   Fig 2: Using Ohmmeter To Inspect Voltage Regulator (2 Of 2)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. Standard: When the positive and negative poles between terminals F and E are exchanged, there is continuity in one direction, but not the other. 

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

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

Fig 3: Using Ohmmeter To Inspect Rotor (1 Of 2)

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

If there is no continuity, replace the rotor.

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

Fig 4: Using Ohmmeter To Inspect Rotor (2 Of 2)

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If there is continuity, replace the rotor.

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

   If rough or scored, replace the rotor.

2. Using vernier calipers, measure the slip ring diameter.
   Fig 5: Measuring Slip Ring Diameter
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   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.

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

Fig 6: Using Ohmmeter To Inspect Stator (1 Of 2)

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

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

Fig 7: Using Ohmmeter To Inspect Stator (2 Of 2)

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If there is continuity, replace the drive end frame assembly

Using vernier calipers, measure the exposed brush length.

Fig 8: Measuring Exposed Brush Length

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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.

1. Check the positive (+) rectifier.
   1. Using an ohmmeter, connect one tester probe to the positive (+) terminal and the other to each rectifier terminal.
   Fig 9: Using Ohmmeter To Inspect Rectifiers (1 Of 2)
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   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.

2. Check the negative (-) rectifier.
   1. Using an ohmmeter, connect one tester probe to each negative (-) terminal and the other to each rectifier terminal.
   Fig 10: Using Ohmmeter To Inspect Rectifiers (2 Of 2)
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   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 that the bearing is not rough or worn.

If necessary, replace the bearing (See REPLACEMENT ).