Section 358 (Charging System - Generators & Regulators): Generator: Inspection

1. Using an ohmmeter, check the continuity between terminals F and B. See Fig 1.

   Standard  : 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 voltage regulator.

   Fig 1: Testing Voltage Regulator Continuity Terminals F To B

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2. Using an ohmmeter, check the continuity between terminals F and E. See Fig 2.

   Standard  : 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 voltage regulator.

Fig 2: Testing Voltage Regulator Continuity Terminals F To E

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Using an ohmmeter, check that there is continuity between the slip rings. See Fig 3.

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

If there is no continuity, replace the rotor.

Fig 3: Testing Rotor Slip Ring Continuity

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Using an ohmmeter, check that there is no continuity between the slip ring and rotor. See Fig 4.

If there is continuity, replace the rotor.

Fig 4: Testing Rotor Slip Ring To Rotor Continuity

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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. See Fig 5.

For diameter, see illustration. See Fig 6.

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

Fig 5: Measuring Slip ring Diameter

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Fig 6: Slip Ring Diameter Chart

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Using an ohmmeter, check that there is continuity between the coil leads. See Fig 7.

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

Fig 7: Testing Coil Leads For Continuity

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Using an ohmmeter, check that there is no continuity between the coil lead and drive end frame. See Fig 8.

If there is continuity, replace the drive end frame assembly.

Fig 8: Testing Coil Lead To End Frame For Continuity

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Using vernier calipers, measure the exposed brush length. See Fig 9.

For exposed length, see illustration, See Fig 10.

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

Fig 9: Measuring Brush Length

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Fig 10: Exposed Brush Length Chart

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1. Using an ohmmeter, connect one tester probe to the positive (+) terminal and the other to each rectifier terminal. See Fig 11.
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 11: Testing Positive Rectifier

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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 12: Testing Negative Rectifier

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Check that the bearing is not rough or worn.

If necessary, replace the bearing. See REPLACEMENT .