Alternator - Chrysler Dodge Aries I

DESCRIPTION

Chrysler vehicles use either a conventional 60 or 78 amp alternator or 114 amp high capacity alternator. The 114 amp alternator has 12 silicon rectifiers that convert A.C. current into D.C. All other alternators have 6 silicon rectifiers.

Main components are the rotor, stator, rectifiers, end shields and pulley. Output voltage is limited by an external electronic voltage regulator.

TROUBLE SHOOTING

Note. See the TROUBLE SHOOTING - BASIC PROCEDURES article in the GENERAL TROUBLE SHOOTING section.

CHARGING CIRCUIT RESISTANCE

Note. Before making test connections, disconnect battery ground cable at battery negative post to avoid accidental shorting of charging or field circuits.

Scheme 18

1. Disconnect "BAT" lead wire at alternator output terminal. Connect 0-150 amp scale D.C. ammeter in series between alternator "BAT" terminal and disconnected "BAT" lead wire. (Scheme 18) (Scheme 18): Test Meter Connections for Charging Circuit Resistance Test Disconnect negative battery cable before connecting test equipment.
2. Connect positive lead of D.C. voltmeter to disconnected "BAT" lead wire. Connect negative voltmeter lead to battery positive terminal. Disconnect Green (regulator) field lead wire from alterna- tor.
3. Connect jumper from alternator field terminal to ground. Connect tachometer and reconnect battery ground cable. Connect variable carbon pile rheostat (C-3950) to battery terminals. CAUTION: Be sure carbon pile rheostat is in "OPEN" or "OFF" position before connecting leads. To avoid damage, reduce engine speed to idle immediately after starting.
4. Start engine and operate at idle speed. Adjust engine speed and carbon pile rheostat to maintain 20 amps flowing in circuit. Voltmeter reading should not exceed.7 volts.
5. When higher voltage drop is indicated, inspect, clean and tighten all connections in charging circuit. If necessary, test voltage drop at each connection to locate connection with excessive resistance.

Scheme 19

1. Disconnect "BAT" lead wire at alternator output terminal. Connect 0-150 amp scale D.C. ammeter in series between alternator "BAT" terminal and disconnected "BAT" lead wire. (Scheme 19) (Scheme 19): Test Meter Connections for Alternator Current Output Test Be sure carbon pile rheostat is in "Open" or "Off" position before connecting leads.
2. Connect positive lead of D.C. voltmeter (range 0-15 volts minimum) to "BAT" terminal of alternator. Connect negative voltmeter lead to good ground.
3. Disconnect Green field wire (to voltage regulator) at alternator. Connect jumper from alternator field terminal to ground.
4. Connect tachometer and reconnect negative battery cable. Connect variable carbon pile rheostat between battery terminals. CAUTION: Be sure carbon pile rheostat is in "OPEN" or "OFF" position before connecting leads. To avoid damage, reduce engine speed to idle immediately after starting.
5. Start engine and operate at idle. Adjust engine speed and carbon pile rheostat until speed of 900 RPM (114 amp) or 1250 RPM (all others) and voltmeter reading of 13 volts (114 amp) or 15 volts (all others) is obtained. CAUTION: Increase in engine speed should not be high enough to allow voltage to exceed 16 volts.
6. Observe ammeter. Current output should be within specifications. If output is less than specified, alternator should be removed from vehicle and bench tested.

ROTOR COIL

1. Place alternator on insulated surface and connect ohmmeter between alternator field terminals.
2. No reading indicates open rotor coil or defective field brushes.

FIELD COIL

1. Place alternator on insulated surface and connect one ohmmeter lead to either field terminal and one lead to ground (on alternator end shield).
2. Meter reading of continuity indicates grounded field coil.

ROTOR FIELD COIL

1. To test rotor field coil current draw, place alternator on insulated surface and connect jumper between one field terminal of alternator and negative terminal of fully charged battery.
2. Connect test ammeter negative lead to other field terminal of alternator and positive lead to battery positive terminal. 3) Slowly rotate alternator rotor by hand. Observe ammeter reading. Field coil draw should be 5.0-2.5 amps at 12 volts. Low rotor coil draw indicates high resistance in field coil circuit (brushes, slip rings or rotor coil).
3. High rotor coil draw indicates possible shorted rotor coil or grounded rotor. No reading indicates an open rotor or defective brushes. Reverse connections to field terminals and retest.

RECTIFIER

Note. DO NOT break plastic cases of diodes, cases are for protection against corrosion. Always touch test probe to metal strap nearest diode.

1. Remove nuts from studs on terminal block securing stator windings, positive and negative rectifier straps to block. CAUTION: To prevent possible damage to brush assemblies, remove before separating end shields. Stator is laminated, DO NOT burr stator or end shield.
2. Lift off stator winding terminals and carefully pry stator assembly from end shield.
3. Test rectifiers with 12 volt battery and test lamp equipped with a No. 67 bulb (4 candle power). Connect one test lamp lead to positive battery post and other lead to end of test probe. Attach second probe to battery negative terminal.
4. Measure rectifier continuity with one probe touching heat sink and other probe to rectifier top strap.
5. Reverse probes. If lamp lights with current flow in one direction only, rectifier is satisfactory. If lamp lights with probes either way, rectifier is shorted.
6. If lamp does not light either way, rectifier is open. Test each rectifier in both assemblies. Replace defective rectifiers. Lamp should light in same direction for all rectifiers of each assembly.

STATOR

Note. The 114 amp alternator can be checked for stator grounds only. Due to "Delta" windings, it cannot be checked for opens or shorts with common automotive shop equipment. If stator is not grounded and all other components check correctly, suspect either open or short in stator.

1. Separate stator from both end shields. Press one test probe firmly against clean spot (varnish removed) on stator frame. Stator must be bare and clean. Press other probe firmly to each 3 phase lead terminal, one at a time. If lamp lights, stator lead is grounded.
2. On all but 114 amp alternators, press test probe firmly on one phase terminal lead and touch second probe to other two stator leads, one at a time.
3. Test lamp should light when probe contacts each terminal. If lamp does not light, stator winding is open.
4. If stator tested is grounded or open, install new stator.

Scheme 20

Scheme 21

1. Test rotor for grounded, open or shorted field coils using ohmmeter.
2. Test for grounded field coil by connecting ohmmeter leads between each slip ring and rotor shaft. (Scheme 20) (Scheme 20): Ohmmeter Hookup for Testing Alternator Rotor for Grounds The 60 and 78 amp model is shown; 114 amp model similar. NOTE: When performing Rotor Test, ohmmeter should be set for infinite reading with probes apart and zero with probes shorted. Ohmmeter should read infinite. If reading is zero or higher, rotor is grounded.
3. Check for open field coil by connecting ohmmeter across slip rings. (Scheme 21): Testing Alternator Rotor for Opens or Shorts Using Ohmmeter The 60 and 78 amp model is shown; 114 amp model similar.
4. Ohmmeter reading should be 1.7-2.1 ohms (114 amp) or 1.5-2.0 ohms (all others) with rotor at room temperature.
5. Resistance between 2.5 and 3.0 ohms would result from alternator rotors that have been operated on vehicle at higher engine compartment temperatures.
6. Readings above 3.5 ohms indicate high resistance and may require rotor replacement. Readings below 1.7 ohms (114 amp) or 1.5 ohms (all others) indicate field coil is shorted.

DISASSEMBLY

1. Remove brush screws and insulating washers. Lift brush assemblies from end shield. Stator is laminated. Use care not to burr stator or end shield.
2. Remove through bolts. Pry between stator and drive end shield with blade of screwdriver. Carefully separate drive end shield, pulley and rotor assembly from stator and rectifier end shield assembly. NOTE: If negative heat sink diode straps (all except 114 amp) are on top of positive heat sink straps, loosen 4 hex-head screws on negative rectifier and heat sink assembly and lift heat sink assembly out of rectifier end shield.
3. On all but 114 amp alternator, remove nut and washer from "BAT" output terminal on outside of rectifier end shield. Remove round plastic insulator. Turn end shield over and remove nut and washer assembly from end shield stud. Remove screw that attaches capacitor to case.
4. Lift out insulated washer, capacitor and heat sink assembly. Remove round plastic insulator from "BAT" terminal hole. Remove mica insulator from end shield stud. If negative heat sink diode straps were under positive heat sink diode straps, remove negative rectifier and heat sink assembly.
5. On 114 amp alternator, remove nut and insulator (from inside end shield) securing heat sink assembly to end shield stud. Remove screw attaching capacitor to end shield. Remove capacitor and insulator.
6. From outside of rectifier end shield, remove nut and insulator attaching positive heat sink assembly stud to end shield. Remove positive and negative heat sink assemblies, noting location of insulator. Remove terminal block from end shield.
7. Pulley is an interference fit on rotor shaft. Use puller (C-4467 for 114 amp and C-4068 or C-4333 for all others) to remove. On 114 amp alternator, remove screws attaching bearing retainer to drive end shield. On all others, pry retainer from shield with screwdriver. To separate rotor from end shield, support shield and tap rotor shaft with plastic hammer.
8. Drive end bearing is an interference fit to rotor shaft. Use puller (C-4333 for 114 amp and C-4068 or C-4333 for all others) to remove. Rectifier end shield bearing is a press fit. Use support under shield when pressing bearing out with press tool (C-4330 for 114 amp and C-3770A and C-3925 for all others).

SLIP RING REPLACEMENT

Slip rings are not serviced separately but replaced with rotor assembly.

Scheme 22

1. On all except 114 amp alternator, position grease retainer on rotor shaft. Press retainer onto shaft using installer tool (C-3921). Plastic grease retainer is properly positioned when inner bore of installer tool bottoms on rotor shaft. NOTE: New bearings are prelubricated, additional lubrication is not required.
2. On all alternators, place rectifier end shield bearing on base of bearing installer tool (C-4330-1 for 114 amp and C-4201 for all others). Place alternator end shield on top of bearing so bearing is properly aligned with bore.
3. Place support tool (C-4330-2 for 114 amp and C-4201 for all others) under end shield. Press bearing in until it bottoms in rectifier end shield. Insert drive end bearing into drive end shield. Install bearing retainer plate to hold bearing.
4. On 114 amp alternator, position bearing retainer into place. Install mounting screws and tighten to 19-29 INCH lbs. (2-3 N.m). On all models except 114 amp, a metal spacer is supplied with replacement rotors and ball bearings, but is not part of original alternator. Place spacer on pulley end of rotor shaft first.
5. On all models, position bearing and drive end shield on rotor shaft. While supporting rotor shaft, press bearing and end shield into position on rotor shaft with arbor press and pressing tool (C-3858). (Scheme 21)
6. Support rotor shaft so pressing force is on pulley hub and rotor shaft. Install pulley on rotor shaft. Press pulley onto rotor shaft until pulley contacts inner race of drive end bearing. DO NOT exceed 6800 pounds of force to install pulley. DO NOT hammer on pulley.
7. Install mica insulator on heat sink mounting stud in end shield. Install round plastic insulator in battery stud hole in end shield. Flat side of insulator faces up. (Scheme 22): Installing Drive End Shield & Bearing on Rotor Shaft All except 114 amp alternator shown. CAUTION: Be sure bearing is installed squarely or bearing damage will occur. Press bearing onto rotor shaft until bearing contacts rotor spacer.
8. Install positive heat sink assembly by placing battery terminal through round plastic insulator and capacitor end over heat sink mounting stud. Guide rectifier straps over studs on terminal block. Install capacitor terminal over heat sink stud. Install capacitor insulator. Be sure insulator properly seats in capacitor terminal and heat sink hole. CAUTION: Be sure nuts are tightened or failure may occur. DO NOT over-tighten metal screws or insulated washers may break.
9. Install capacitor bracket to end shield. Tighten attaching screw to 30-40 INCH lbs. (3-5 N.m). Install positive heat sink lock washer and nut. Tighten nut to 20-30 INCH lbs. (2-3 N.m).
10. Turn end shield over and install round plastic insulator over battery terminal (flat side up). Install washer and nut and tighten to 30-50 INCH lbs. (3-6 N.m). Install negative rectifier and heat sink assembly into end shield. Place diode straps on terminal block studs.
11. Install screws through end shield and into negative heat sink. Tighten to 19-29 INCH lbs. (2-3 N.m). Position stator over rectifier end shield and install stator leads to terminal block.
12. Press stator into end shield. Tighten winding terminal nuts to 11-17 INCH lbs. (1-2 N.m). Route stator leads so they do not contact rotor or sharp edge of negative heat sink.
13. Position rotor and drive end shield assembly over stator and rectifier end shield assembly. Align through bolt holes. Compress stator and both end shields by hand and install through bolts. Tighten through bolts to 25-55 INCH lbs. (3-6 N.m).
14. Install field brushes in insulated holders. Position vertical and horizontal field brushes in proper location in rectifier end shield. On 114 amp alternator, install long terminal on bottom and short terminal on top.
15. On all models, place insulating washer, lock washer and attaching screw on each field brush terminal. Tighten to 15-35 INCH lbs. (2-4 N.m). Be sure brushes are NOT grounded.
16. Slowly rotate pulley by hand to ensure rotor fan blades do not contact stator winding leads. Install alternator and adjust drive belt.
17. Connect alternator output (BAT), two field (FLD) and ground (GND) leads. Connect negative battery cable. Start engine. Observe alternator operation and test current output.

Exploded View of Chrysler Corp. 60 & 78 Amp Alternator The 60 or 78 amp alternator has 6 silicon rectifiers and 114 amp alternator has 12. Scheme 23

Exploded View of Chrysler Corp. 114 Amp Alternator The 114 amp alternator has Delta windings and can be checked for stator grounding only. Scheme 24

Charging Circuit Service Diagnosis Guide Check all Chrysler Corp. alternators with this chart. Scheme 25

SPECIFICATIONS

ALTERNATOR SPECIFICATIONS

See also:
• TROUBLE SHOOTING - BASIC PROCEDURES