STARTING AND CHARGING SYSTEM 6D3-11
Warning
Do not reverse S and L connections as this will destroy the
warning lamp circuit of the regulator.
Ensure good electrical contact beween generator earth and
battery negative,
Operation
With the Iginiton switch turnded "ON", current is supplied via
the warning lamp to the "L" terminal of the regulator. Base
current is fed to T15 causing it to turn on, current then flows
from B+ through the rotor winding via the regulator brushes
and the collector emitter junction of T15 to earth completing the
circuit. The current in the rotor causes a magnetic field
between adjacent poles to be created, this field is rotated and
cuts the windings of the stator at right angles inducing a
voltage into them.
As the speed is increased this induced voltage increases and
results in curent being rectified in the 3 phase diode bridge and
supplied as DC to the B+ output and hence to the battery.
When the voltage at the B+ terminal of the battery reaches
around 14.2 volts, this voltage is monitored by the "S" lead and
turns the regulator Hybrid base current to T15 OFF removing
rotor current, resulting in a decrease in output voltage to below
the regulating voltage, T15 base current turns ON and the
whole cycle is repeated very rapidly.
D38 protects T15 and the regulator against the back voltage
developed across the rotor winding when T15 turns OFF.
The new generated EP regulators incorporate current limiting in
the warning lamp circuit.
Backup Regulation
The EP regulator will limit the output voltage to a safe level
should either the main B+ cable or the battery sense wire
become decoupled, the output voltage will be slightly above the
normal setting(1-3 volts).
Start up phase
When the Iginition switch is turned on and the engine is not
running, the current to the rotor is reduced by switching it on
and off at a 50% duty cycle, the frequency is approximately 4
KHz and may be audible at times.
This is quite normal, once the engine is started normal
regulation commences.
Warning lamp failure
Should the warning lamp fail, the generator will self excite by
deriving a small current from the phase connecion allowing the
voltage to build up to regulating level.
Note: no filed current will flow when the engine is cranking.