Saab 95 1967, Service Manual

Page: 224 / 610

INTERNAL WIRING
The alternator is for 12 V and internally air-cooled, has a
12-pole;fork-type rotor and is equipped with six silicon
diodes for rectification. To each of the three stator wind-
ing loops is connected an exciter diode. Their common
junction constitutes the terminal D+.
The six rectification diodes are arranged as an A.C. bridge-
coupling. i.e. three diodes are connected for normal po-
larity (anode on supply terminal), and three diodes for
reversed polarity (anode on housing).
According to polarity, the diode carrier is fitted insulated
from ground or direct connected to a ground contact, res-
pectively. Between these two carriers is located insulated
the carrier of the exciter diode.
The stator winding are star-coupled (see wiring diagram).
The rotor carries the ring shaped exciter coil and is of the
fork-type design, one fork having north polarity and the
other south polarity.
The exciter coil ends are connected to the slip-rings to re-
ceive the exciter current.
To
consumers
Exciter
winding
{a indicator
DESCRIPTION
When the ignition key is turned to ignition position, the
circuit is closed.
The current goes from the ignition lock to the charge indi-
cator light, to connection 0+ on the voltage regulator, via
the breaker contact to connection DF on the alternator,
to the carbon brushes and the exciter coil, whereupon the
circuit is grounded. ' - . ‘
In this way the rotor is excited, and a magnetic field Inl-
tiated. When the rotor begins to rotate, an alternating
current is formed in the stator windings, which when pas-
sing the rectifier diodes is rectified and led to the battery
via connection 8+.
The voltage received from the stator windings is also pas-
sing via the exciter rectifiers to the voltage regulator, and
affects the coil in the voltage regulator that guides the
breaker.
When the voltage reaches 14 V or more, the magnetic field
of the coil becomes so strong that the current passing the
breaker is cut off.
The current to the exciter winding is then forced to go
Voltage Regulator AD 14 V
Alternator
KI H
14V 35A20
82162
wmmc DIAGRAM FOR A.C. ALTERNATOR
321 —8