Generator
The GEN IV V8 engine is fitted with a Mitsubishi 140 amp generator. This generator is mounted on the lower, left-hand side of the engine. It has an internally mounted regulator, a single lower mounting lug and no external cooling fans.
The generator is 3 phase, incorporating a rotor with 6 pole pairs and 2 (internal) cooling fans, one on the drive end and one on the slip-ring end. The rotor is supported by ball bearing races in both the drive and slip-ring end housings. The stator surrounds the rotor and has a 3-phase delta connected output winding on a ring shaped lamination pack.
The output of the stator winding is rectified by 6 diodes within the slip-ring end housing. Excitation current is supplied to the rotor field coil via the voltage regulator, the brushes and slip-rings. The electronic voltage regulator requires no adjustment in service.
The generator has 2 external connections:
| • | B+ lead to the battery positive terminal |
| • | L lead to the 3k ohm resistor (50mA max) |
| • | Ground connection (via the installation bolts) |
Circuit Description
With the ignition switched ON, current is supplied via resistance to the L terminal of the regulator with a maximum sinking current of 50mA. This allows current to flow (within the regulator) from the generator B+ terminal to the brushes and rotor winding.
The current in the rotor winding creates magnetic fields between adjacent rotor poles. As the rotor spins, the stator windings cut through this field at right angles and induce voltage. As the speed increases, this induced voltage increases. Current then flows through the 3-phase diode bridge in the rectifier to convert the AC voltage to DC. This is supplied to the B+ output and then to the battery.
The regulator B terminal monitors the system voltage. When this voltage reconnects approximately 14.5 volts, the regulator opens the circuit through the rotor winding, causing the generator output voltage to drop. When the regulator senses a voltage below a preset value, of the B Terminal, the regulator closes the circuit through the rotor winding and voltage to the battery again increases. This cycle repeats very rapidly.
Current does not flow through the rotor winding when the engine is cranking.
Warning Lamp Conditions
The regulator L terminal remains low when it detects a fault condition in the generator or the external circuits. The terminal remains low until all faults are repaired.
Fault conditions include:
| • | Open circuit or excessive voltage drop in the B+ cable |
| • | Open circuit in the generator phase connection |
| • | Overcharge of the battery |
| • | Short circuit in the regulator output stage |
| • | Open circuit in the rotor winding |
| • | Poor contact between the rectifier and the regulator |
| • | Poor contact between the battery terminals and cables |
