DESCRIPTION
Mitsubishi alternators are conventional 3-phase, self-rectifying type units containing 6 diodes (3 positive and 3 negative) which are used to rectify current. A case-mounted Integrated Circuit (IC) regulator is used on all models.
| Model | Volt/Amps | Part No. | ||
|---|---|---|---|---|
| Mazda | ||||
| B2000 | 13.5/50 | A00IT23370 | ||
| B2200 | 13.5/40 | A00IT23479 | ||
| GLC | 12/50 | (1) E56318300A | ||
| RX7 | ||||
| 12A Engine | 12/55 | (1) A5T30574 | ||
| 13B Engine | 12/60 | (1) 2A5T40374 | ||
| 626 | 12/60 | (1) FE0118300R | ||
| (1) Vehicle manufacturer's part number. | ||||
| (1) | Vehicle manufacturer's part number. |
APPLICATION
ON VEHICLE TEST
| CAUTION | DO NOT short across any alternator terminals or run vehicle with any wires disconnected. Battery must be fully charged for tests to be accurate. |
Scheme 1
Scheme 2
- With ignition switch off, check voltage at "R" terminal and "L" terminal. Reading at both terminals should be 0 volts. If not 0 volts, alternator is defective.
- Turn ignition switch on but do not start engine. Voltage at "L" should be 1-3 volts. If voltage is 0, alternator and regulator are defective.
- If voltage at "L" is close to battery voltage with ignition on, short circuit the "F" terminal to rear alternator housing. (Scheme 1) (Scheme 1): Alternator "F" Terminal Location. Terminal is located.8" (20 mm) below the hole.
- Read the voltage at "L" with "F" terminal shorted. If voltage is lower than battery voltage, regulator is defective. If voltage is close to battery voltage, alternator is defective.
- With ignition switch off and battery ground cable disconnected, connect ammeter between alternator terminal "B" and cable. Connect voltmeter between "B" (+) terminal and ground. (Scheme 2) (Scheme 2): Alternator Output Test Arrangement
- Start engine and accelerate to 2000-3000 RPM. Turn on all lights and check ammeter for output.
DISASSEMBLY
- After removing through bolts, insert screwdriver between front housing and stator to separate.
- Hold the rotor in a soft jawed vice. Remove pulley nut, pulley, fan, and spacer. Remove rotor drive end housing by lightly tapping end housing with a soft mallet.
- To separate stator from diode end housing, unsolder 3 negative diode leads and connections between diodes. Hold the stator lead with a needle nose plier to prevent rectifier from overheating.
- Remove condenser from the "B" terminal. Unsolder the "L" and "B" terminal from the rectifier assembly. Lift out rectifier assembly and brush holder.
Diode Assemblies
- Check each diode with ohmmeter in forward and reverse direction. If the diode shows large resistance in one direction and small resistance in other direction, diode is normal.
- If diode shows small resistance in both directions, it is shorted. If large resistance is shown in both directions, diode is open. Heat sink and diodes are replaced as an assembly.
Rotor Field Continuity
Check continuity across field coil slip rings. A reading of 3-4 ohms must be obtained. If there is no continuity, replace rotor.
Rotor Field Coil Ground
Check continuity between individual slip rings and rotor core/shaft. If there is continuity, coil or slip ring is grounded, replace rotor.
Stator Coil Ground
Ensure no continuity exists between stator coil leads and stator core.
Stator Coil Continuity
Check continuity between leads of stator coil. If there is no continuity, replace stator.
Brush Wear Limit
Brushes must be replaced when worn to 1/3 of original length. This limit is indicated by a wear limit line on the side of each brush.
Brush Spring Pressure
Standard tension should be 12-16 oz. (340-453 g). Replace if less than 7 oz. (198 g) or if springs are corroded.
Brushes
To remove brushes from holder, unsolder pigtail from terminal. To replace, solder pigtail to terminal ensure that 1/4" of brush will be located in brush holder.
Diodes
The diodes and rectifier are serviced as an assembly. If any diodes are defective, replace rectifier assembly.
Drive End Bearing
Remove bearing retainer set screws. Press bearing out of front housing.
Rear Bearing
Remove rear bearing from housing assembly using a press or bearing puller.
Voltage Regulator
The voltage regulator and brush holder are combined in one unit. If regulator is found to be defective, replace as an assembly.
REASSEMBLY
Reassemble by reversing disassembly procedures. Soldering of rectifier leads should be done in less than 5 seconds to prevent damage to diodes. When installing the rotor assembly in the rear housing, hold the brushes in position by inserting a stiff piece of wire into the access hole in rear housing.
