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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. Part number. Disassembly.
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ALTERNATOROVERHAUL 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 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
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
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 • 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