Charging System: Generator: Inspection

1. Using an ohmmeter, measure the resistance between terminals F and B.

   Standard: 

   When the positive and negative poles between terminals F and B are exchanged, there is a resistance of Below 1 Ω in one way but a resistance of 10 kΩ or higher in another way. 

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

   Fig 1: Measuring Resistance Between Terminals F & B

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Using an ohmmeter, measure the resistance between terminals F and E.

   Standard: 

   When the positive and negative poles between terminals F and E are exchanged, there is a resistance of Below 1 Ω in one way but a resistance of 10 kΩ or higher in another way. 

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

   Fig 2: Measuring Resistance Between Terminals F & E

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Using an ohmmeter, measure the resistance between the slip rings.

Standard resistance: 

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

Fig 3: Measuring Resistance Between Slip Rings

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

Standard: 10 kΩ or higher 

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

Fig 4: Measuring Resistance Between Slip Ring & Rotor

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

INSPECT SLIP RINGS 

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.

   Standard diameter: 14.2 to 14.4 mm (0.559 to 0.567 in.) 

   Fig 5: Measuring Slip Ring Diameter (12V 90 A Type)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Minimum diameter: 

   SLIP RING: MINIMUM DIAMETER
   
   

   12 V 90 A type	12.8 mm (0.504 in.)
   12 V 100 A type	14.0 mm (0.551 in.)

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

INSPECT STATOR FOR OPEN CIRCUIT 

Using an ohmmeter, measure the resistance between the coil leads.

Standard: Below 1 Ω 

If the result is not as specified, replace the drive end frame assembly.

Fig 6: Measuring Resistance Between Coil Leads (12V 90 A Type)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

INSPECT STATOR FOR GROUND 

Using an ohmmeter, measure the resistance between the coil lead and drive end frame.

Standard: 10 kΩ or higher 

If the result is not as specified, replace the drive end frame assembly.

Fig 7: Measuring Resistance Between Coil Lead & Drive End Frame (12V 90 A Type)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Using vernier calipers, measure the exposed brush length.

Standard exposed length: 9.5 to 11.5 mm (0.374 to 0.453 in.) 

Fig 8: Measuring Exposed Brush Length

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Minimum exposed length: 

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

INSPECT RECTIFIERS (RECTIFIER HOLDER) 

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 a resistance of Below 1 Ω and the other shows a resistance of 10 kΩ or higher.

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

      Fig 9: Inspecting Rectifiers Terminal (12V 90 A Type)

      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 a resistance of Below 1 Ω and the other shows a resistance of 10 kΩ or higher.

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

      Fig 10: Connecting One Tester Probe To Each Negative (-) Terminal

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Check that the bearing is not rough or worn. If necessary, replace the bearing (see REPLACEMENT ).