Page 221
TESTING
General
Please note the following points before testin
nator or parts thereof:
Diodes may only be tested with D.c. volta
ing 24 V.
Glim glowing lamps (110 V or 220 v) May not be used
for insulation or short circuit tests, if the diodes are in
the circuit.
The 80 V 40 W test voltage for the stator Winding insula-
tion test may only be applied if the diodes are discon-
nected.
While the engine is running, battery terminals may not
be disconnected to check the charging current on the ve-
hicle.
Semi-conductors are extremely sensitive to heat. To pre-
vent excessive heat when soldering, use a pair of flat pliers
to hold the supply wire near the diode. (Use a hot iron
and be as quick as possible.) Any mechanical damage to
the diode connecting wires must be avoided, e.g. do not
bend or load the wire directly on the diode (breakage due
to vibration).
The battery must be switched off or disconnected before
any repair work commences on the alternator, either
while in the vehicle or on the test bench.
Only instruments having not more than 8 V power supply
may be used for measuring resistances on the assembled
alternator.
g the alter-
ges not exceed-
Testing the alternator in test bench
On the test bench, the alternator must be driven with its
own pulley. All connections must be made with correct
size cable shoes, or on the regulator with spade terminals.
Do not improvise the battery connection.
A 12 V battery must be connected parallel to the alter-
nator before any testing commences except for the regu-
lating voltage test and the nominal voltage and speed tests.
The battery will act as a buffer and smooth off any peak
voltages arising from switching on or off the load.
Peak voltages exceeding the maximum permissible value
will damage the rectification effect of diodes. The max!-
mum permissible peak voltage on silicon diodes is approx.
50 Vv,
Excitation
et
As opposed to D.C. generators, alternato
selfexciting properties after long storage.
rs can lose their
Therefore a
charge indicator light of 12 V and minimum 2 W must be
Connected between terminals 61 and B+ according to wir-
ing diagram. The pre-exciting current will then flow
through the charge indicator light, D+/61 on the alter-
nator, D+/61 on the regulator, the closed regulator con-
tacts and DF to the exciter coil fitted to the rotor. It is
Most important that the charge indicator light bulb is
minimum 2 W. Self-exciting commences as soon as the
exciter diodes are conducting at about 1 to 2 volts. From
there on, the voltage increases rapidly, the voltage differ-
ence on the charge indicator light bulb decreases, and the
bulb will go out as soon as battery voltage is achieved.
Mounting of the alternator
The shape of the alternator housing does not permit a per-
fect mounting on the V block of the test bench. Therefore,
a special mounting unit is available.
WARNING
When testing the alternator it must be mounted in
its ordinary attachments. It must not be clamped
on to the test bench.
Testing with regulator
Mount the regulator to the test bench. Connect the alter-
nator to the voltage regulator. Do not interchange connec-
tions! Connect the exciter current ammeter to terminal
DF on alternator. Switch on battery; switch on charge in-
dicator light. Connect voltmeter to terminal B+. To pre-
excite the alternator, increase the speed from zero until
the output voltage is approx. 14 V and decrease speed
again.
let tran O tills man far en generatorspanning pa ca 14 V
och sedan sanks varvtalet ater.
Testing the regulating voltage at half exciter current
Connect voltmeter to terminal D+/61,
Run the still excited alternator without load and without
battery. Increase speed until exciter current falls to half
its maximum value. Check the voltage. Regulating voltage
13.5 to 14.2 V (68°F = 20°C).
Testing the nominal voltage speed
Connect Voltmeter to B+. The alternator should also run
without load and without battery. Adjust the speed until
the output voltage is exactly 12 V. Check with tachome-
ter.
Nominal voltage speed 800—900 r/min.
SAAB 321—5
Febr 1977
Page 222
Testing 2/3 of maximum output current
Switch on battery and load the alternator. Adjust the
speed to exactly 2 000 r/min. The alternator output must
now be 2/3 of maximum current = 23 A.
Testing the RPM at maximum output
Leave the battery switched on. Increase the load on alter-
nator and let it warm up. Increase speed. Max. output
(35 A—14 V) must be achieved at 2 700—3 700 r/min
(warm).
Testing the alternator components
Testing of diodes
Use only a test lamp not exceeding 24 V or an Ohmmeter.
Always disconnect the diodes from the stator windings
before individual testing commences. Due to the 3-phase
bridge connection of the rectifier, a faulty diode could
otherwise not be detected. The positive diodes connected
between B+ and phase are conducting from supply wire
to the housing and insulate in the reverse direction. The
diodes between phase and B— (reversed polarity) are con-
ducting from housing to supply and insulate from supply
to housing.
Connect the test lamp (up to 24 V) in series to the diode
to be tested. On diodes of normal polarity, the test lamp
will light up if B+ is connected to the anode. The lamp
must not light up if B+ is applied to the housing (cathode).
On diodes of reversed polarity, the bulb must light up if
B+ is connected to the supply (cathode) but not if the di-
rection of current is reversed. Faults of diodes can be open
circuit in the conducting direction due to excessive cur-
rent and too much heat or conducting in both directions,
in most cases due to excessive voltages during operation.
des with OHM-meter
be tested with an Ohm-meter. The
ode is very small in the conducting
), whereas the resistance in the
uch higher (e.g. a few K Ohms).
Testing of dio
Similarly, diodes can
resistance of a good di
direction (e.g. a few Ohms
insulating direction is very m
Testing of stator
Ground (diodes unsoldered).
Short Circuit to
Short circuit to ground of stators can be tested as usual
with a test lamp up to 40 V. “—_
With diodes connected, short circuit to ground can be
tested if their insulating direction is considered. The posi-
tive terminal of the tester must be applied to the stator
winding and the negative to the housing.
Note the test voltage: Not more than 24 V.
Short circuit of windings (diodes unsoldered)
As for D.C. generators a short circuit tester can be used
to test the stator. However, this test is only possible if the
alternator is dismantled, i.e. the stator must be removed.
Furthermore, short circuit of windings can also be ascer-
tained with an Ohm-meter. Three measurements must be
taken, one each on every two-phase wires: U — V,U-W
and V — W.
The resistance value of each measurement must be the
same, 0.26 ohm + 10 % (at 68°F = 20°C).
Testing the exciter winding (rotor)
The Testers (test voltage 40 V) are suitable to test the in-
sulation of exciter winding and slip rings.
Check the exciter winding resistance from slip ring to slip
ring. The resistance value must be 4.0—4.4 Ohms.
Supply Su
pply
(Anode) (Cathode)
Conducting Dir. ;
Insulating Dir. Conducting Dir
SDA Housing
321-6
—Diod
Housing
Febr 1977
Page 223
As from chassis No. 47.296 ang 443.387
GENERAL
During driving, the alternator supplies the cy
red by the various consumer units and also c
battery. oie
The alternator pulley is finned to induce a current of air
through the alternator, thus dispelling the heat d
there while it is running,
The alternator is driven by a belt from the crankshaft belt
pulley, and is located to the right of the engine.
rent requi-
harges the
eveloped
is IMPORTANT
The battery must always be connected, when the
alternator is running.
Do not mix up the battery connections, confusion
leads to serious damage to the alternator.
The alternator requires very little maintenance, be-
cause carbon brushes and commutators are not
needed for the output current.
The alternator has two slip rings respectively two
carbon brushes to transmit exciting current to the
alternator field windings on the rotor.
The load on these brushes and slip rings is, however,
that light that normally they do not require super-
vision.
Maintenance with regular intervals is therefore not
prescribed for this alternator. Repair of the A.C.
generator should be carried out by a specialized
service garage, as it is vital that disassembly and
testing are carried out correctly. Even minor mis-
takes may cause great damage.
reeo-
NOTE
For exitation of the alternator, use the charge indi-
Cator light. This must be of 1.2—2.0 W.
|
WARNING
When electrowelding on a car equipped with an al-
ternator, the battery ground- and all connections on
the alternator shall be disconnected before. Other-
wise damage will be caused to the rectifier diodes.
As from chassis No. 95753002472 and 96752013172 an
alternative alternator is used. It is identic with the one
used in Saab 99 up to and incl. model 1974, but minor
modifications are made.
The slip ring bearing bracket is turned half turn to suit
the installation bracket. The fan disc is exchanged against
the Saab 95/96 disc. A new alternator stay is introduced
which is interchangeable with earlier design. The alter-
nator which is not stocked as spare part is marked with
Bosch No. 0 120 400 850. Concerning integral parts, see
spare parts catalogue, Saab 99.
ALTERNATOR
1. Drive end frame
2. Stator
3, Slip ring end
4, Rotor
SAAS
Febr 1977
bracket
321-7
Page 224
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.
4
To consumers
Battery 12 V
——S74
rts
oat |
|
ali I |
indicator, '
. 4 oe
, |
a
eer
DESCRIPTION
When the ignition key is turned to ignition position, the
circuit is closed. 7 Ps,
The current goes from the ignition lock to the charge indi-
cator light, to connection D+ 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 ini-
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 B+.
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 1 14 V
Charge
Jin
nat.
KI == 14V 35420
nlf
see ~ Ser ae
aaa
—-—.—]
|
|
|
Alternator
|
|
|
|
|
S$ 2162
WIRING DIAGRAM FOR A.C. ALTERNATOR
321-8 SAAB
Febr 1977
Page 225
through the resistance and is thus reduced, wh
the magnetic field strength diminishes ‘Seid ith Roe
strength of the alternating current generated in i the
winding. Thus, the voltage regulator limits the ce stator
maximum approx. 14 V.
The charge indicator light is also affected by the vol
from the stator windings via connection D+ an a tage
tor so, that the difference in voltage on either side o
charge indicator light is equalized and the light goes = ‘4
Thus, you can make sure that the alternator charges ut,
A current limiting relay is not required, since the alter:
nator itself limits the current intensity. At high RPM on
the alternator, when the periodicity of the created, alter-
native voltage is high and when the intensity of thie cur-
rent consumed has reached a certain height, the resulting
resistance (impedance) is so great that a further current
increase is not possible.
tage to
DESIGNATION
The Bosch designation of the alternator is
14V35A20
The meaning of the type designation is:
K1 =
K 1 ~——\ 14V 35A 20
x 100 = 2 000 r/min
(r/min for 2/3 of
max. current out-
put)
Maximum current
Maximum voltage
Direction of rota-
tion
Design: 1 ... fork or
claw type rotor,
2 ... single pole
rotor, 3... brush-
less
Pole housing dia-
meter @
Febr 1977
TERMINALS
D+: Output of exciter diodes, connection of regulator
D+,
DF: Connection to the exciter coil and for the DF of
the regulator,
B+: Battery connection.
The control lamp is connected to D+ on the voltage reg-
ulator. Connection to the D— of the regulator is made via
a cable in the 3-pole connector.
CABLE CONNECTIONS AND CABLE COLOURS, ALTER-
NATOR, AS FROM CHASSIS NO. 47.296 RESP. 443.387
1. 85 grey to B+
2. 74 grey to B+
3, Black to ground (only mode! 1970)
4. 73 yellow to DF
5. 72e red to D+
6. 49 black to D—
QUICK CHECKING
If the charge indicator light does not go out, the first
thing to do is to check that the alternator belt is not slip-
ping and/or that the cable connections have not loosened,
321-9
see
Page 226
an WARNING
t run the engine at 4 higher speed than2000 |
r/min, as there is a risk of damage to the power con- |
/ ’
sumers being caused by overvoltage. |
Do no
If the indicator light goes out immediately, the charging
regulator is defective and must be renewed.
If the indicator light flashes or lights continuously, the
alternator must be overhauled.
REMOVAL AND INSTALLATION
1. Disconnect the battery negative cable.
NOTE! The engine must be stopped before detach-
ment of cable.
2. Disconnect the alternator cables, retaining and adjust-
ADJUSTMENT OF FAN BELT TENSION ing bolts and take off the fan belt.
Lift out the alternator.
Refit the alternator in the reverse sequence,
5. Adjust the fan belt tension so that the belt can be pres-
sed down approx. 0.3 in. (approx. 7 mm) at a load of
15 N (3.5 Ib., 1.5 kp) half way between the pulleys.
wo
1. Adjusting screw
2. Retaining screw
ried
If the lamp still glows after checking in this way, the cause
can be determined in the following manner.
Remove the connector from the charging regulator.
Connect a cable between the red cable's terminal D+ and DISASSEMBLY
the yellow cable’s terminal DF.
1. Hold the belt pulley with a suitable tool, and loosen
the nut with a 0.87 in. (22 mm) open end wrench.
Loosen the belt pulley and the fan,
2. On the drive end plate, mark out the location of the
attachment ear.
Loosen the fixing screws of the drive end plate, and
take out of the stator the rotor together with the drive
end plate.
3. Place the drive end plate on a suitable support, and
press out the rotor — gently. Now it is possible to re-
move the bearing. Take care not to allow the rotor —
when same comes loose from the drive end plate — to
fall down and be damaged.
4. Remove the ball bearin
g at the slip rin end, by means
of a suitable puller, , .
$2073
TERMINALS DF AND D+ CONNECTED
Start the engine and let it run at max. 2 000 r/min while
watching the charge indicator light.
321-10 SAAB
Febr 1977
Page 227
ASSEMBLING
5. Insert the rotor and screw the assembly together. Make
The length of the brushes must be checked before the al Sure that the drive bearing housing is correctly posi-
ternator is assembled, The minimum is 0,354 in tioned relative to the slip ring bearing housing. Press
(9
but if they are under 0.551 in. (14 mm) they sh oe the brushes down from the outside with a screwdriver
ould be
replaced, See ‘Changing brushes”. or similar.
1, Pack the ball bearings with Bosch Ft 1 v 34 grease
Press the ball bearing into the housing with the en-
closed side facing the drive end.
2. Press the drive bearing housing on to the rotor.
3. Press on the ball bearing on the slip ring side. The en-
closed side faces the slip rings.
A
PRESSING DOWN THE BRUSHES pi
penne
6. Fit the fan and belt pulley. The large spacer is to be
placed between the fan and the belt pulley. The small
spacer is to be placed between the belt pulley and the
spring washer. Tighten the nut to a torque of 23—29
ft.lb. (34—39 Nm, 3.5—4 kpm).
S 998
PRESSING THE SLIP RING BALL BEARING INTO POSITION CHANGING BRUSHES
Min, length of the brushes is 0.354 in. (9 mm). If the al-
ternator is renovated the brushes shall be replaced if they
are under 0.551 in. (14 mm).
1, Mark the position of the tension lug on the drive bear-
ing housing. Undo the bearing housing retaining screws
and remove the rotor with the bearing housing from
the stator.
Undo both nuts holding the rectifier bridge in place.
3, Undo the terminal screw of the connecting wire to the
brush unit assembly.
(Later alternator models are fitted with AMP-connec-
4. Put the spring washer into the bearing seat. Push up
the brushes and secure them with the brush springs
(this is easier if the brush unit assembly |s removed).
i)
tions.)
BRUSHES PUSHED UP AND SECURED
SAAB 321-11
Febr 1977
Page 228
REMOVING THE BRUSH UNIT ASSEMBLY
5. Disconnect the wires with the help of a soldering iron;
DISCONNECTING THE BRUSH UNIT ASSEMBLY WIRE the brushes can then be removed. When resoldering
the wire connections, make sure that no solder flows
into the wires.
4. Undo the brush unit assembly retaining screws and re-
move the assembly.
UNSOLDERING THE BRUSH UNIT TERMINALS
6. Push up the brushes and secure
springs. Fit the brush unit asse
that the spring washer is in its
ing seat,
them with the brush
mbly and make sure
correct place in the bear-
UNSCREWING THE BRUSH UNIT ASSEMBLY
321—12 Febr 1977
Page 229
TESTING
ecru taeaa poser testing the alter-
ke only be tested with D.c., voltages not exceed-
Glim glowing lamps (110 V or 220 V) may not be used
for insulation or short circuit tests, as they may damage
the diodes.
The 80 V 40 W test voltage for the stator winding insula-
tion test may only be applied if the diodes are discon-
nected,
While the engine is running, battery terminals may not be
disconnected to check the charging current on the vehicle.
Semi-conductors are extremely sensitive to heat. To pre-
vent excessive heat when soldering, use a pair of flat pliers
to hold the supply wire near the diode, (Use a hot iron and
be as quick as possible.) Any mechanical damage to the
diode connecting wires must be avoided, e.g. do not bend
or load the wire directly on the diode.
The battery must be switched off or disconnected before
any repair work commences on the alternator, either while
in the vehicle or on the test bench.
Only instruments having not more than 8 V voltage may
be used for measuring resistances on the accembled alter-
nator.
Testing alternator on bench
On the test bench, the alternator must be driven with its
own pulley only. All connections must be made with cor-
rect size cable shoes, or with spade terminals, Do not im-
provise the battery connection.
A 12 V battery must be connected parallel to the alter-
nator when testing. The battery will act as a buffer and
smooth off any peak voltages arising from switching on
or off the load.
Peak voltages exceeding the maximum permissible value
will damage the rectification effect of diodes. The maxi-
mum permissible peak voltage on silicon diodes is approx.
50 V.
Excitation
Contrary to D.C. generators, alte
citing properties after long storag
rnators lose their selfex-
e. Therefore 4 charge in-
Febr 1977
dicator light of 12 V and minimum 1.2—2.0 W must be
connected between terminals D+ and B+ according to
wiring diagram. The pre-exciting current will then flow
through the charge indicator light, D+ on the alternator,
DF to the exciter coil fitted to the rotor. It is most im-
portant that the charge indicator light bulb is minimum
1.2—2.0 W. Self-exciting commences as soon as the alter-
nator voltage opens the exciter diodes, which occurs at
about 1 to 2 volts. From there on, the voltage increases
rapidly, the voltage difference on the charge indicator
light bulb decreases, and the bulb will go out as soon as
battery voltage is achieved.
Mounting of the alternator
The alternator can be tested in most types of alternator
test benches. In some cases it may be necessary to add
special mounting- and driving devices.
vennes
saeee
CAUTION
When testing the alternator, it must be mounted in
its normal attachment and not e.g. fastened by
damping.
Testing with regulator
Mount the alternator to the test bench and connect it to
the voltage regulator.
Do not mix up connections!
Connect the exciter current ammeter to terminal DF on
alternator. Switch on battery; switch on charge indicator
light. Connect voltmeter to terminal B+. To pre-excite
the alternator, increase the speed from zero until the out-
put voltage is approx. 14 V, then decrease speed again.
Testing 2/3 of maximum output current
Switch on battery and load the alternator. Adjust the
speed to exactly 2 000 r/min. The alternator output must
now be 2/3 of maximum current = 23 A.
Testing the r/min at maximum output
Leave the battery switched on. Increase the load on al-
ternator and let it warm up. Increase speed. Max. output
(35 A at 14 V) must be achieved at 2 700—3 700 r/min.
321-13
Page 230
Testing alternator Parts
Use only a test lamp not exceeding 24 V or an Ohm-me-
ter,
Always disconnect the silicon diodes from the stator wind-
ings before individual testing of the conducting- and insu-
lating directions commences, a faulty diode could other-
wise not be detected. The positive diodes connected be-
tween B+ and phase are conducting from supply wire to
the housing and insulate in the reverse direction. The ne-
gative diodes between phase and B— (reversed polarity)
are conducting from housing to supply and insulate from
supply to housing.
Connect the test lamp in series to the diode to be tested.
On diodes of normal polarity, the test lamp will light up
if B+ is connected to the anode, The lamp must not light
up if B+ is applied to the housing (cathode).
On diodes of reversed polarity, the bulb must light up if
B+ is connected to the supply (cathode) but not if the di-
rection of current is reversed,
Faults of diodes can be open circuit in the conducting di-
rection due to excessive current and, as a consequence,
too much heat. Conducting in both directions is in most
cases due to excessive voltages during operation.
Testing of diodes with ohm-meter
The diodes can also be tested with an Ohm-meter. The
resistance of a good diode is small in the conducting di-
rection (e.g. a few Ohms), whereas the resistance in the
insulating direction is considerably higher (e.g, a few kilo
Ohms).
Supply
(Anode)
Conducting Dir.
Housing
+Diod
321-14
Insulating Dir.
g f stator windings
a to Ground (diodes unsoldered).
Short circuit to ground of stator winding can be tested
as usual with a test lamp of max. 40 V. .
Also with diodes connected, short circult to ground can
be tested if their insulating direction is considered. The
positive terminal of the tester must be applied to the
stator winding and the negative to the diode housing.
Note the test voltage: Not more than 24 V.
Short circuit of stator windings (diodes unsoldered)
This short circuit can be established with a winding tester,
but is only possible with the alternator dismantled. A
further possibility is to measure simultaneously the resis-
tance for two phases. By three measurements you can
find out the stator windings resistance deviations. If the
phases are marked U, V and W, the measurements shall
be made between U—V, U—W and V—W. The value of
each measurement shall be 0.20—0.22 Ohms (at 68°F =
+20°C).
Testing the exciter winding (rotor)
With an Ohm-meter, check the exciter winding resistance
from slip ring to slip ring.
The resistance value must be 4.0—4.4 Ohms.
The exciter windings and the insulation of slip rings is
tested with regard to short circuit to ground (test voltage
40 V).
Supply
(Cathode)
Conducting Dir.
Housing
Febr 1977