The GTO 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 star connected output winding on a ring shaped lamination pack.

The output of the stator winding is rectified by 8 diodes within the slip-rind 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 4 external connections:

With the ignition switched on , current is supplied via the warning lamp to the L terminal of the regulator. This allows current to flow (within the regulator) from the generator B+ 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 winding cut through this field at right angles and induce voltage. As the speed increases, this induced voltage increases. Current then flows through the three-phase diode bridge in the rectifier to convert the AC voltage to DC. This is supplied to the B+ output ant hen to the battery.

The regulator S terminal monitors the system voltage. When this voltage reaches approximately 14.2 volts, the regulator breaks the circuit through the rotor winding, causing the generator output voltage to drop. When the regulator S terminal senses a voltage below a preset value, the regulator completes the circuit and voltage to the battery again increases. This cycle repeats very rapidly.

If the warning lamp fails, the generator self excites by using current from the phase connection until the voltage builds up to the regulating level

Current does not flow through the rotor winding when the engine is cranking.

With the ignition on and the engine at rest, the regulator defaults to active standby mode. This limits the current through the rotor by switching ON and OFF at 50 percent duty cycle with a frequency of approximately 4 kHz. This is audible at times.

The regulator compares voltage at the B+ terminal with voltage sensed at the S terminal. The regulator defaults to backup mode if the difference exceeds a preset value. Backup mode limits the output voltage to a safe level approximately 1-3 volts above the normal setting.

The regulator illuminate the warning lamp when it detects a fault condition in the generator or the external circuits. The warning lamp remains illuminated until all faults are repaired.

Fault conditions include: