Page 190 - CTS - Mechanic Diesel - TP

MECHANIC DIESEL - CITS

Alternator Bench Tests
If the on-vehicle checks have indicated that the alternator is defective, it should be removed for bench testing and
replacement. Specific procedures for removal, disassembly, inspection, and assembly are noted in the appropriate
repair manuals. Only the electrical bench tests are covered here.
• Always disconnect the battery ground (-) cable before removing the alternator.
• Refer to the appropriate repair manual for test specifications.
An ohmmeter is used for electrical bench tests on the rotor, stator, and diode rectifier. The following steps are
typical.
Rotor Tests
• Check the rotor for an open circuit by measuring for resistance between the slip rings.
• Some resistance (less than 5 ohms) indicates continuity.
• If there is no continuity (infinite resistance), replace the rotor.

• Check the rotor for grounded circuits by measuring for resistance between the rotor and slip ring.
• Any amount of resistance indicates a ground (continuity). The resistance should be infinite.
• If not, replace the rotor.

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CITS : Automotive - Mechanic Diesel - Exercise 10.2 CITS : Automotive - Mechanic Diesel - Exercise 10.2