Toyota 3R-B 1969, Repair Manual

Page: 143 / 193

8-4 C H A R G I N G S Y S T E M - Alt ernator &1 Regulator
A rotor coil wound in the shape of a doughnut is connected to the two slip rings
which a re actuated by an exciting current from the two brushes, and the rotor
is mounted onto the bearings located at the end fr a m e s , and re v o lv e s within the
stator.
T h e stator is composed of a la rge number of windings assembled on the inside
of a laminated c o r e that is attached to the fra m es . T h e stator coil is of a three-
phase " Y " type. A n alternating current generated at the stator coil is converted
to a direct current by the six rectifiers which a re mounted at the rectifier holders.
T h e rectifier is of a silicone diode which has a v e r y high resistance to a flow
of current in one direction, but it has a v e r y low resistance in the other d ir e c ­
tion . T h e r e f o r e , with a p r o p e r polarity, the low resistance allows the current
to flow from the stator Coil to the battery, and the high resistance prevents a
r e v e r s e current from the battery. M o re o v e r , the stator coil has a self-limiting
characteristic in- limiting the current flow in its coil to a p r e - s e t value even the
revolution in c rea se s exceedingly. F o r these re a s on s , a current control such as
a cut-out relay and a current limiter a re not required fo r the alternator.
T h e alternator regulator is composed of the voltage regulator and the voltage
r e l a y . T h e function of the voltage regulator in the charging system is to re gu ­
late the generating voltage of the stator coil to a p r e - s e t value controlling the
exciting cu rrent of the ro tor coil.
T h e voltage relay is provided to prevent the flickering of the headlights and the
ir r e g u la r vibration of the ammeter needle when the engine is operated at idle
revolution.
Specification:
R S . R T 4 3 L . 52L & R K 1 7 1B s e r ie s
A lte rn a to r P a r t N o .
Voltage
Maximum output current at 14 volts
under heated condition
N o load revolution at 14 volts
under heated condition
P e r m is s ib le maximum revolution
A llo w a b le surrounding temperature
Ground
D irection of revolution
Weight
T es tin g specification:
N o load revolution at normal
temperature
Output revolution at normal
tem perature
27020-21011
12 volts
40 am peres
820 rp m
12,000 rpm
-40 °C ~ 80 °C (-40 ° F ~ 176 ° F )
N egative
C lo ck w is e as seen from pulley
Approximately 4 .8 kg (10 .6 lbs)
14 volts, z e r o a m p e re, at 800 + 150
rpm
14 volts, 40 am peres at less than
3,500 rpm
R K 4 4 . 101* and 171 s e r ie s
A lt e r n a to r P a r t N o .
V oltage
Maximum output cu rrent at 14 volts
under heated condition
N o load revolution at 14 volts
under heated condition
27020-22010
12 volts
25 am peres
950 rpm