Alternator (FA20): Inspection

Standard length: 22.5 mm {0.885 in}

Minimum length: 5.0 mm {0.196 in}

Fig 1: Identifying Brush Standard And Minimum Length

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

1. Measure the resistance according to the value(s) in the table below.

Fig 2: Checking Resistance Between Generator Coil Assembly Lead Wires

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If the result is not as specified, replace the generator coil assembly.

1. Measure the resistance according to the value(s) in the table below.

Fig 3: Checking Resistance Between Generator Coil Assembly Lead Wire And Stator Core

Courtesy of SUBARU OF AMERICA, INC.

If the result is not as specified, replace the generator coil assembly.

1. Measure the resistance according to the value(s) in the table below.

Fig 4: Checking Generator Rotor Assembly For Open Circuit

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

1. Measure the resistance according to the value(s) in the table below.

Fig 5: Checking Resistance Between Generator Rotor Assembly Slip Ring And Rotor Core

Courtesy of SUBARU OF AMERICA, INC.

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

1. Using a vernier caliper, measure the diameter of each slip ring.

Standard diameter: 22.7 mm {0.893 in}

Minimum diameter: 22.1 mm {0.870 in}

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

Fig 6: Measuring Slip Ring Diameter Using Vernier Caliper

Courtesy of SUBARU OF AMERICA, INC.

1. Measure the resistance according to the value(s) in the table below.
   Fig 7: Checking Generator Holder With Rectifier Resistance

   Courtesy of SUBARU OF AMERICA, INC.