AUTOMOTIVE TECHNOLOGY ALTERNATOR OVERHAUL AUTOMOTIVE TECHNOLOGY

BEFORE YOU REMOVE ALTERNATOR Pay attention to how wires are connected Pay attention to Alternator oreintation Disconnect Battery!! Check Belt tension and condition Check wiring condition

DISASSEMBLY Disassembly Mark frames for correct reassembly Part number Disassembly Mark frames for correct reassembly Note spacers placement Identify Alternator by Part Number Note Terminal Condition & orientation

INSPECTION OF “COM” END HOUSING Bearing condition Stator windings Pulley condition Brush wear Internal Wiring Connections Component external damage

INSPECTION OF DRIVE END HOUSING (FRAME) Bearing race housings Frame Condition Cracks Wear Stripped threads Mounting boss condition

ROTOR VISUAL INSPECTION Rotor slip ring condition Rotor Windings external condition Shaft condition Cooling Fan condition

TESTING ROTOR FIELD COIL Rotor resistance GM 2.4 to 3.5 ohms Ford 3.0 to 5.5 ohms Chrysler 3.0 to 6.0 ohms Some shop manuals give rotor specifications in amps.

ROTOR TESTING FOR GROUNDED SLIP RINGS Inspect rotor lead soldering area Test rotor for Grounds to shaft Can use ohmmeter Can use 110 Volt continuity tester Check that commutator!

ROTOR TESTING FOR GROUND TO ROTOR FRAME Test rotor for grounds to rotor frame (open circuit cats claw) Should be Inspect cats claw for signs of rubbing on stator

DIODE TESTING Check Positive diodes for one way operation by switching leads. Can test with diode check function of DVOM Can check with 110V diode tester tool. Check Negative Diodes also Must only get continuity one way!!! Note: Diodes can be checked on car with Sun VAT 40

TEST STATOR FOR CONTINUITY Check Stator for Continuity between phases of windings Usually check resistance of windings Must be same resistance

TEST STATOR FOR GROUNDS Make sure Stator windings are not grounded to frame! Inspect windings for worn spots on windings. Check looseness

DELCO REMY 25SI AND 30SI ALTERNATORS

ADVANTAGES OF HEAVY DUTY 25-SI ALTERNATOR BRUSHLESS - ROTOR WORKS ON PERMANENT MAGNETISM BELT OR GEAR DRIVEN 12V, 24V, 32V 85 AMP TO 300 AMP CAPABILITY ELECTRONIC REGULATOR 12V - 24V COMBINATION OUTPUT SOME ARE OIL COOLED

LOTS OF WIRE CONNECTIONS!!!

25SI ROTOR Rotor doesn’t spin in this alternator Stator is stationary also Inspect Rotor and stator for interference Check stator and rotor as any other alternator

25SI ROTOR HOUSING Inspect for interference Inspect bearing races Remove bearing race with bearing splitter Inspect D.E. Bearing Inspect C.E. Bearing Inspect Housing threads and condition

REPAIR Clean components Replace Bearings Replace Brushes and Springs OK to clean in solvent but make sure dry Replace Bearings Don’t spin bearings Inspect races closely Use proper procedures to replace and remove bearings. Replace Brushes and Springs Replace other faulty components

REASSEMBLY Proper Torque Paint Housing if necessary Use Lock Tight on H.D. Alternators Make sure there is no tension on wiring Make sure connections are tight!! Always retest output after Overhaul.

Final Bench Testing Check amperage output Look up specifications In book Listen for abnormal noises Check internal regulator operation Make sure cutoff voltage is correct. Test Light/Indicator circuits also. Reinstall on Vehicle