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Alternator
Swap
GM Wiring
Updated 05-19-2006
On the back of the alternator is the battery lead wire. Usually a red
insulator but not always, and on the SIDE of the case is a place for a
2 wire plastic plug. The plug leads are parallel with the edge of the
case. IF you find an alternator with the 2 wire spades IN LINE with the
fan, this is the older style WITHOUT the internal regulator. Where this
thing plugs in cast on the case below the opening for the plug should
be a number 1 and 2 below the respective terminals. Wire #1 goes to the
key switch accessory terminal with a (10 ohm 10 watt) in line
resister ((if you
have an old style key switch
that does not have an accessory terminal you will need the Radio Shack
part number 276-1661 diode to put in line with the #1 wire. It is
installed with the stripe towards the alternator. This will allow the
car to stop when your key is turned off)), this wire is HOT with the
key in the RUN
position, BUT NOT THE
START POSITION. Wire #2 can be hooked directly to the big battery wire
on the
back of the case, but should be connected to the battery side of the
starter solenoid if the wire run is from one side of the car to the
other. (This is because if the alternator output is high there
will be a voltage drop of about 1 volt from the alternator to the
battery starter solenoid terminal and the rest of the car components
will not have the correct voltage during high charging rates). Wire #2
is a sense voltage source for the regulator. The
idiot light is rather unique. the light is a small dash lamp bulb on a
special plug in base. NORMAL lights require a ground and a hot wire.
THIS LIGHT IS NOT GROUNDED, instead both leads are insulated from the
car body. One side goes to the key switch, where it is fed 12 volts
when the key is ON, and the other goes to #1 on the alternator. With
the key ON and the engine not running, the light lights up, as there is
a voltage difference between the 2 leads. AS the engine is running this
wire has 12 volts across its entire length and the lamp goes out, as
BOTH LEADS have the same voltage, when the alternator is charging. If
the alternator quits charging, then this wire loses its voltage and the
light comes one says I AIN'T WORKING, so you know something is wrong.
Usually on
the GM's the battery wire off the back of the alternator goes to the
battery side terminal of the starter solenoid. There is an in line fuse
here most often on the originals, consisting of a fusible link. Ditto
for the headlights and the rest of the cars wiring needs. If you have
an ammeter, make certain that the STARTER DRAW IS NOT PUT ACROSS THE
TERMINALS OF THE AMMETER. The location of the ammeter can depend on
what you want to know. There are 2 places to put it, which I won't get
to here. A normal GM internal regulator alternator can have an output
from 45-70 amps depending on several variables. By changing the
internal windings and rotor it is possible to get 120-140 amps, but the
life is shortened. You can also have a self excited alternator, by
changing the regulator and then you have NO little wire plug to worry
about, Just the big battery wire. Speaking of which, this battery wire
MUST BE 10 gauge minimum and I like to solder the terminals on the end.
I don't trust crimp connections. If you have to run this wire a long
ways, then the wire MUST BE BIGGER. Delco manuals sometimes call for #1
wire sizes for some alternators and 3/0 for some starters, but you
OUGHT TO SEE THE BATTERIES!!!The following is a picture of the wiring
for the new alternator with old style key and new style key with an
example of the original wiring found in most Studebaker Hawks or Larks.
You will need to check your wiring diagram to make sure the wiring is
the same as that show in the picture below.
|
Mopar
I know most are going to
recommend the one-wire GM setup but I prefer the Mopar unit. If you
start with the standard Stude V8 bracket on the exhaust manifold the
front lug of the Mopar alternator bolts to the front of the Stude
bracket and positions the belt alignment perfectly (assuming you use a
single groove pulley). A piece of angle iron with one hole drilled in
it is welded to the Stude bracket to make the support for the rear lug
of the alternator. The early Mopars ('61-'69) used the same voltage
regulator as the alternator equipped Studies. It's a simple two wire
hookup. The '70 and later used a solid state regulator with three
wires. The regulator can be mounted in the same location as the
original Stude and most of the original wires used.
Alternator Model 10SI 61 amp. from 1984 chevy or 1971
international truck
DESCRIPTION
The
alternator illustrated in Figs. 1 and 2 features a solid state
regulator that is mounted inside the alternator
slip ring end frame. All regulator components
are enclosed into a solid mold, and this unit
along with the brush holder assembly is attached
to the slip ring end frame. The regulator voltage setting never needs
adjusting, and no
provision for adjustment is made.
The
alternator rotor bearings contain a supply of lubricant
sufficiently adequate to eliminate the need for
periodic lubrication. Two brushes carry current
through the two slip rings to the field
coil mounted on the rotor and under normal
conditions will provide long periods of attention-free service.
The stator windings
are assembled on the inside of a laminated
core that forms part of the alternator frame.
A rectifier bridge connected to the stator
windings contains six diodes and electrically changes the stator A. C.
voltages to a D. C.
voltage which appears at the alternator output
terminal. Alternator field current is
supplied through a diode trio which also is
connected to the stator windings. A capacitor, or
condenser, mounted in the end frame protects the
rectifier bridge and diode trio from high
voltages and suppresses radio noise.
No
periodic adjustments or maintenance of any kind are required
on the entire alternator assembly.
OPERATION
Updated 05-19-2006
A typical
wiring diagram is illustrated in Fig. 3. The basic
operating principles are explained as follows. To excite or start the
alternator the
switch is closed, current from the battery flows through
the ammeter and resistor (10 ohm 10 watt) to the alternator No.
1 terminal, through resistor R1, diode Dl,
and the base emitter of transistor TR1 to
ground, and then back to the battery. This turns on
transistor TR1 and current flows through the alternator field coil and
TR1 back to the
battery.
With the
alternator operating, A.C. voltages are generated in the
stator windings, and the stator supplies D. C.
field current through the diode trio, the field,
TR1, and then through the grounded diodes in the
rectifier bridge back to the stator. Also, the
six diodes in the rectifier bridge change the stator A. C. voltages to
a D. C. voltage which
appears between ground and the alternator
'BAT' terminal. As alternator speed increases,
current is provided for charging the energizer
and operating electrical accessories. Also,
with the alternator operating, the same voltage
appears at the 'BAT' and No. 1 terminals,
and the ammeter gauge goes out to indicate
the alternator is producing a charge for the
battery.
The No. 2
terminal on the alternator is always connected to the
battery. but the discharge current is limited to a negligible value by
the high
resistances of R2 and R3. As the alternator speed and voltage increase,
the voltage between R2 and R3
increases to the point where zener diode D2 conducts. Transistor TR2
then turns on and
TR1 turns off. With TR1 off, the field
current and system voltage decrease, and D2 then
blocks current flow, causing TR1 to turn
back on. The field current and system voltage
increase, and this cycle then repeats many
times per second to limit the alternator voltage to
a preset value.
Capacitor Cl
smooths out the voltage across R3, resistor R4
prevents excessive current through TR1 at high
temperatures, and diode D3 prevents high
induced voltages in the field windings when TR1
turns off. Resistor R2 is a thermistor, which
causes the regulated voltage to vary with temperature, thus providing
the optimum voltage
for charging the battery.
TROUBLESHOOTING
In order
to locate and correct defects in the charging system in the
shortest possible time, the following
procedures should be used. Only a portion of these
procedures need be performed. It will never
be necessary to perform all the procedures in
order to locate the trouble.
To avoid
damage to the electrical equipment, always observe the
following precautions:
Do not
polarize the alternator.
Do not
short across or ground any of the terminals in
the charging circuit. Never operate
the alternator with the output terminal
open circuited.
Make sure
the alternator and battery have the same
ground polarity.
When
connecting a charger or a booster battery to
the vehicle battery, connect negative to
negative and positive to positive.
Trouble in
the charging system will show up as one or more of the
following conditions:
An
undercharged battery as evidenced by slow cranking
and low specific gravity readings.
An
overcharged battery, as evidenced by excessive
water usage.
Undercharged Battery
This
condition, as evidenced by slow cranking and low specific gravity
readings, can be caused by one or more of the following conditions
1. Insure that the undercharged condition has not been caused by
accessories having been left on for extended periods.
2. Check the drive belt for proper tens ton.
3. Inspect the wiring for defects. Check all connections for tightness
and cleanliness, including the slip connectors at the alternator tor
and
firewall and the cable clamps and battery posts.
4. With ignition switch on and all wiring harness leads connected,
connect a voltmeter from:
a. Alternator "BAT" terminal to ground.
b. Alternator No. 1 terminal to ground,
c. Alternator No. 2 terminal to ground.
A zero reading indicates an open between voltmeter connection and
battery. Opens in the wiring harness connected between the No. 2
alternator terminal and battery may be be tween the terminals, at the
crimp between the harness wire and terminal, or in the wire.
5. If previous Steps 1 through 4 check satisfactorily, check
alternator as follows:
a. Disconnect battery ground cable.
b. Connect an ammeter in the circuit at the "BAT" terminal of the
alternator,
c. Reconnect battery ground cable.
d. Turn on radio, windshield wipers, lights high beam and blower motor
high speed. Connect a carbon pile across the battery.
e. Operate engine at moderate speed as re quired and adjust carbon pile
as required to obtain maximum current output.
f. If ampere output is within 10 percent of rated output as stamped on
alternator frame, alternator is not defective; re check Steps 1 through
5.
g. If ampere output is not within 10 percent of rated output, ground
the field winding by inserting a screwdriver into the test hole, Fig.
4. NOTE: Tab is within 3/4" of casting surface. Do not force screw
driver deeper than 1" into end frame.
h. Operate engine at moderate speed as required and adjust carbon pile
as required to obtain maximum current output.
i. If output is within 10 percent of rated output, replace regulator
and check field winding.
j. If output is not within 10 percent of rated output, check the field
winding, diode trio, rectifier bridge and stator.
k. Remove ammeter from alternator and turn accessories off.
Overcharged Battery
1. Connect a voltmeter from alternator No. 2 terminal to ground. If
reading is zero, No. 2 lead circuit is open.
2. If battery and No. 2 lead circuit check good but an obvious
overcharge condition exists, as evidenced by excessive battery water
usage, proceed as follows:
a, Separate end frames. Check field winding for shorts. If shorted,
replace rotor and regulator.
b. Connect ohmmeter using lowest range scale from brush lead clip to
end frame as shown in Step 1, Fig. 5, then reverse lead connections.
c. If both readings are zero, either the brush lead clip is grounded or
regulator is defective.
d. A grounded brush lead clip can result from omission of insulating
washer, Fig.5, omission of insulating sleeve over screw, or damaged
insulating sleeve. Remove screw to inspect sleeve. If satisfactory,
replace regulator.
DISASSEMBLY
To disassemble the alternator, remove the four thru- bolts and separate
the drive end frame and rotor assembly from the stator assembly by
prying apart with a screwdriver at the stator slot. A scribe mark will
help locate the parts in the same position during assembly. After
disassembly place a piece of tape over the slip ring end frame bearing
to prevent entry of dirt and other foreign material and also place a
piece of tape over the shaft on the slip ring end. NOTE: Use pressure-
sensitive tape and not friction tape, which would leave a gum my
deposit on the shaft. If brushes are to be reused, clean with a soft,
dry cloth.
To remove the drive end frame from the rotor, place the rotor in a vise
and tighten only enough to permit removal of the shaft nut.
NOTE: Avoid excessive tightening, as this may cause distortion of the
rotor. Remove the shaft nut, washer, pulley, fan, and the collar; and
then separate the drive end frame from the rotor shaft.
Rotor Field Winding
Checks
To check for opens, connect the test lamp or ohmmeter to each slip
ring. If the lamp fails to light or if the ohmmeter reading is high
(infinite), the winding is open, Fig. 6.
The winding is checked for short circuits or excessive resistance by
connecting a battery and ammeter in series with the edges of the two
slip rings. Note the ammeter reading and refer to specifications. An
ammeter reading above the specified value indicates shorted windings; a
reading below the specified value indicates excessive resistance. An
alternate method is to check the resistance of the field by connecting
an ohmmeter to the two slip rings, Fig. 6. If the resistance reading is
below the specified value, the winding is shorted; if above the
specified value, the winding has excessive resistance. The specified
resistance value can be determined by dividing the voltage by the
current. Remember that the winding resistance and ammeter readings will
vary slightly with winding temperature changes. If the rotor is not
defective but the alternator fails to supply rated output, the defect
is in the diode trio, rectifier bridge or stator.
Diode Trio Check
The diode trio is identified in Fig. 5. First connect an ohmmeter using
lowest range scale from brush lead clip to end frame as shown in Step
2, Fig. 5; then reverse lead connections. If both readings are the
same, check for grounded brush lead clip caused by omission of
insulating washer, Fig. 5, omission of insulating sleeve over screw, or
damaged insulating sleeve. Remove screw to inspect sleeve. if screw
assembly is correct and both ohm-meter readings are the same, replace
regulator.
To check the diode trio, remove it from the end frame assembly by
detaching the three nuts, the attaching screw, and removing the stator
assembly. Note that the insulating washer on the screw is assembled
over the top of the diode trio connector. Connect an ohmmeter
having a 1-1/2 volt cell, and using the lowest range scale, to the
single connector and to one of the three connectors, Fig. 7. Observe
the reading. Then reverse the ohmmeter leads to the same two
connectors. If both readings are the same, replace the diode trio. A
good diode trio will give one high and one low reading. Repeat this
same test between the single connector and each of the other two
connectors.
NOTE: Figs. 5 and 7 illustrate two diode trios differing in appearance.
Either one of these diode trios may be used in these alternators, and
the two are completely interchangeable.
Rectifier Bridge Check
Note that the rectifier bridge has a grounded heat sink and an
insulated heat sink connected to the output terminal. Also note the
insulating washer located between the insulated heat sink and end
frame, Fig. 8.
To check the rectifier bridge, connect the ohmmeter to the grounded
heat sink and one of the three terminals, Fig. 8. Then reverse
the lead connections to the grounded heat sink and same terminal. If
both readings are the same, replace the rectifier bridge. A good
rectifier bridge will give one high and one low reading. Repeat this
same test between the grounded heat sink and the other two terminals
and between the insulated heat sink and each of the three terminals.
This makes a total of six checks with two readings taken for each check.
NOTE: If rectifier bridge is constructed as shown in Fig. 9, check with
the rectifier bridge mounted in the end frame in the same manner as
Fig. 8-- except connect ohmmeter pressing down very firmly onto flat
metal connector and not onto threaded stud, Fig. 9.
The ohmmeter check of the rectifier bridge and of the diode trio is a
valid and accurate check. Do not replace either unit unless at least
one pair of readings is the same. CAUTION: Do not use high voltage to
check these units, such as a 110-volt test lamp.
Fig. 9 Rectifier Bridge Check
To replace the rectifier bridge, remove the attaching screw and the
"BAT" terminal screw and disconnect the capacitor lead. Note the
insulator between the insulated heat sink and end frame, Fig. 8.
Rectifier bridges may vary in appearance but are completely
interchangeable in these alternators.
Stator Check
The stator windings may be checked with a 110-volt test lamp or an
ohmmeter. If the lamp lights or if the meter reading is low when
connected from any stator lead to the frame, the windings are grounded.
If the lamp fails to light or if the meter reading is high when
successively connected between each pair of stator leads, the windings
are open, Fig. 10.
A short circuit in the stator windings is difficult to locate without
laboratory test equipment, due to the low resistance of the windings.
However, if all other electrical checks are normal and the alternator
fails to supply rated output, shorted stator windings are indicated.
Also, a shorted stator can cause the indicator lamp to be on with the
engine at low speed.
Brush Holder and
Regulator Replacement
After removing the three attaching nuts, the stator and diode trio
screw, Fig. 8, the brush holder and regulator may be replaced by
removing the two remaining screws. Note the two insulators located over
the top of the brush clips in Fig. 5 and that these two screws have
special insulating sleeves over the screw body above the threads. The
third mounting screw may or may not have an insulating sleeve,
if not, this screw must not be interchanged with either one of
the other two screws, as aground may result causing no output or
uncontrolled alternator output. Regulators may vary in appearance but
are completely interchangeable in these alternators.
Fig. 10 Stator Windings Check
Slip Ring Servicing
If the slip rings are dirty, they may be cleaned and finished with 400
grain or finer polishing cloth. Spin the rotor and hold the polishing
cloth against the slip rings until they are clean. NOTE: The rotor must
be rotated in order that the slip rings will be cleaned evenly.
Cleaning the slip rings by hand without spinning the rotor may result
in flat spots on the slip rings causing brush noise.
Slip rings which are rough or out of round should be trued in a lathe
to . 002 inch maximum indicator reading. Remove only enough material to
make the rings smooth and round. Finish with 400 grain or finer
polishing cloth and blow away all dust.
Bearing Removal and
Lubrication
The bearing in the drive end frame can be removed by removing the
retainer plate screws and then pressing the bearing from the end frame.
If the bearing is in satisfactory condition, it may be reused, and it
should be filled one- quarter full with Delco- Remy lubricant No.
1948791 before reassembly. NOTE: Do not overfill, as this may cause the
bearing to overheat. Use only 1948791 lubricant.
Bearing
Installation
To install a new bearing, press in with a tube or collar that just fits
over the outer race with the bearing and slinger assembled into the end
frame as shown in Fig. 11. It is recommended that a new retainer plate
be installed if the felt seal in the retainer plate is hardened or
excessively worn. Fill the cavity between the retainer plate and
bearing with 1948791 lubricant.
Fig. 11 Drive End Bearing (Flat Washer
May
Be
Used
Instead
of Slinger)
The bearing in the slip ring end frame should be replaced if its grease
supply is exhausted. No attempt should be made to re lubricate and
reuse the bearing. To remove the bearing from the slip ring end frame,
press out with a tube or collar that just fits inside the end frame
housing. Press from the outside of the housing towards the
inside.
To install a new bearing, place a flat plate over the bearing and press
in from the outside towards the inside of the frame until the bearing
is flush with the outside of the end frame. Support the inside of the
frame with a hollow cylinder to prevent breakage of the end frame. Use
extreme care to avoid misalignment or otherwise placing undue stress on
the bearing.
It is recommended that a new seal be installed whenever the bearing is
replaced. Press the seal in with the lip of the seal toward the rotor
when assembled--that is, away from the bearing. Lightly coat the seal
lip with oil to facilitate assembly of the shaft into the bearing.
REASSEMBLY
Reassembly is the reverse of disassembly. To install the slip ring end
frame assembly to the rotor and drive end frame assembly, remove
the tape over the bearing and shaft and make sure the shaft is
perfectly clean after removing the tape. Insert a pin through the holes
to hold up the brushes. Carefully install the shaft into the slip ring
end frame assembly to avoid damage to the seal. After tightening the
thru-bolts, remove the brush retaining pin to allow the brushes to fall
down onto the slip rings. When installing the pulley, the pulley nut
must be torqued to 60 ft.lbs. If not properly tightened, it is possible
that the nut and pulley could loosen and slip on the shaft.
To assist in tightening the pulley nut, a 5/16 inch hex hole is
provided in the end of the shaft for holding with an Allen wrench. Also
a special 15/16 inch socket wrench, Fig. 12, which is applicable to the
nut is available from the Snap-On Tool Company. This special 1/2 inch
drive socket wrench is designed with a cutout to receive the Allen
wrench and may be used in conjunction with a torque indicating wrench.
Where desired, a length of 3/8 inch pipe may be applied to the Allen
wrench to provide additional leverage for the holding effort.
The special 15/16 inch socket wrench, Fig.12, is available from your
local Snap-On representative under their number S-8183.
Fig. 12 Torquing Pulley Nut
Alternator Bench Check
To check the alternator in a test stand, proceed as follows:
1. Make connections as shown in Fig. 13, except leave the carbon pile
disconnected. NOTE: Ground polarity of battery and alternator must be
the same. Use a fully charged battery and a 10 ohm resistor rated at
six watts or more between the alternator No. 1 terminal and the battery.
2. Slowly increase the alternator speed and observe the voltage.
3. If the voltage is uncontrolled with speed and increases above 15.5
volts on a 12-volt system or 31 volts on a 24-volt system, check for a
grounded brush lead clip. If not grounded, replace the regulator and
check field winding. NOTE: The battery must be fully charged when
making this check.
Fig. 13 Connections for Bench Check
4. If voltage is below 15. 5 volts on a 12-volt system, connect the
carbon pile as shown.
5. Operate the alternator at moderate speed as required and adjust the
carbon pile as required to obtain maximum current output.
6. If output is within 10 percent of rated output as stamped on
alternator frame, alternator is good.
7. If output is not within 10 percent of rated output, keep energizer
or battery loaded with carbon pile and ground alternator field, Fig. 13.
8. Operate alternator at moderate speed and adjust carbon pile as
required to obtain maximum output.
9. If output is within 10 percent of rated output, replace regulator
and check field winding.
10. If output is not within 10 percent of rated output, check the field
winding, diode trio, rectifier bridge and stator as previously covered.