Charging Systems: Charging: Generator: Inspection

1. Check if the rotor has an open circuit.
   1. Using an ohmmeter, measure the resistance between the slip rings.

      Standard: 2.3 to 2.7 Ω at 20°C (68°F) 

   If the resistance is not as specified, replace the rotor.

   Fig 1: Measuring Resistance Between Slip Rings

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Check if the rotor is grounded.

   Using an ohmmeter, check the resistance between the slip ring and the rotor core.

   Standard: 10 kΩ or higher 

   If the resistance is not as specified, replace the rotor.

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

   If rough or scored, replace the rotor.

   Fig 2: Checking Resistance Between Slip Ring And Rotor Core

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Using a vernier caliper, measure the slip ring diameter.

   Specified diameter: 

   14.2 to 14.4 mm (0.559 to 0.567 in.) 

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

Fig 3: Measuring Slip Ring Diameter Using Vernier Caliper

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Using a vernier caliper, measure the exposed brush length.

Standard exposed brush length: 

10.5 mm (0.413 in.) 

Minimum exposed brush length: 4.5 mm (0.177 in.) 

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

Fig 4: Measuring Exposed Brush Length Using Vernier Caliper

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Check that the bearing is not rough or worn.

If necessary, replace the generator rotor.

Fig 5: Inspecting Bearing

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