The internal fan Mitsubishi alternator has a brush holder and an integral voltage regulator, with the voltage sensitive regulator controlling the charge rate according to battery condition. It consists of a stator enclosing a fixed coil winding, rotor having a shaft wound coil, rectifier or diode pack, and an IC regulator. The brushes on the slip rings feed an electrical current into the rotor windings, which generates a magnetic field in the rotor and produces three-phase alternating current (AC) in the star wound stator. The electrical output from the stator windings is rectified to direct current (DC) using a pack of diodes housed within the alternator slip ring end bracket as the storage batteries cannot be charged with AC. The output voltage is controlled by the internal characteristics of the integrated-circuit regulator and the alternator, with a non-adjustable voltage regulator. There's no need for an electrical cut out unit as the diodes stop reverse current. Precautions to take while servicing include that the battery should be connected with the negative terminal to earth, short circuit or grounding of terminals in charging circuit should be avoided, switching off the battery before plugging-on a charger, booster batteries in parallel should be connected and regular checking of drive belt and battery terminal is to be done. Follow these steps to test the alternator on the vehicle. If the warning lamp glows after starting the engine or the charge rate seems incorrect, turn off the engine. Next, Check the drive belt. Clean battery terminals. Finally, check that the battery is fully charged. Once you start the engine and achieve normal operating temperature, disconnect the negative lead from the battery; remove the alternator output lead; connect an ammeter and voltmeter to measure voltage and amperage output. Alternator's overhaul or replacement may be necessary if readings are out of specifications. To remove the alternator, disconnect the negative battery terminal and the wiring from it. Remove the drive belt. Then unbolt the alternator. The reverse sequence of disassembly was followed in the installation. Dis-assembly of alternator is a job which requires technical knowledge and special tools. It is usually better to get it repaired or exchange unit.