Repair (cont.)

TM 5-930-233-14

TM 4930-14/1

AIR COMPRESSOR ASSEMBLY

5-13. ALTERNATOR - REPAIR - (Cont.)

Repair (cont.)

(7)

Test stator assembly for grounds and opens as follows:

(a)

Connect the multimeter (set to lowest resistance range) to two pairs of stator leads; if reading is very

high (over 10 ohms) the stator winding is open.

(b)

To test the stator for grounds, connect the multimeter from any stator lead to the ground screw or the

shell, and note the reading. If reading is very low, the stator is shorted to ground (defective).

(8)

Test rotor assembly for grounds between slip ring and shaft, using a multimeter. An open circuit from either

slip ring to shaft is a correct condition.

(9)

Perform resistance check on rotor assembly windings using a multimeter; resistance should be between 11 to

14 ohms.

(10) Test voltage regulator by connecting multimeter leads to regulator leads as follows:

(a)

Connect multimeter lead (+) to regulator yellow lead and multimeter lead (-) to regulator red lead;

multimeter should indicate between 300 to 350 ohms.

(b)

Connect multimeter lead (+) to regulator red lead and multimeter lead (-) to regulator yellow lead;

multimeter should indicate an open circuit.

(c)

If above readings are not obtained, replace regulator.

(11) Inspect fan for cracked or broken fins. Check fan bore for wear.

(12) Inspect pulley for worn drive surfaces and condition of key groove. Check pulley bore for wear.

(13) Inspect front bearing cavity for evidence of wear. Check condition of retainer recess.

(14) Check slip rings for pitting, roughness, or burned spots. If surface is worn beyond repair, replace entire rotor

assembly.

(15) Inspect rotor shaft for key slot wear, worn bearing surfaces, scuff marks on pole fingers, and condition of

threads on pulley nut.

(16) Inspect bearings for scored, pitted, scratched, cracked, or chipped races.

(17) Replace any part or component that is damaged, worn or defective.

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