| From "Operation and
Maintenance manual TM-10-1485"
THE GENERATOR
The generator used on the
Model 640 and Model 741 military machines is known as the
"Indian Auto-Lite."It is of the third brush, 6
volt, regulating type and can be adjusted to increase or
reduce the charging rate.It is driven by an enclosed chain
direct from the motor sprocket on the left side of the
machine, forward of the motor base.
To Adjust Charging Rate
1. Loosen clamp screw
holding the steel band to which the "Auto-Lite"
name plate is attached.
2. Turn the clamp so that
the opening is in line with the oil cup and slide off,
taking care not to damage the gasket under the steel band.
3. With the engine running,
move the third (moveable) brush toward the front of the
machine to increase the charging rate or back toward the
engine to reduce it - checking the ammeter swing until the
correct output is obtained. (The output should be regulated
to break even with all lighting equipment normally used in
operation.) To check the movement of the ammeter, race the
engine slightly to obtain the maximum register.
4. If the armature contact
at the brushes appears dirty it should be cleaned and
polished with No. .00 sandpaper before trying to regulate.
(Emery cloth should never be used.)
5. When properly regulated -
replace the metal band and gasket and tighten the clamp
screw.
Removing the Generator From
the Machine
Note: - Disconnect battery
ground terminal to prevent short.
1. Remove the cover on the
left side of the engine over the generator drive.
2. Remove the nut holding
the drive sprocket (right-hand thread).
3. Remove the sprocket and key.
4. Disconnect the wire leading to the circuit breaker on the
right side of the generator.
5. Loosen the clamp connection under the generator.
6. Remove the nut on the left side of the frame holding the
generator to a position where the bolt can be removed from
the frame to let the generator drop free.
Disassembly of the Generator
In disassembling the
generator, the oil sealing felt washers should be examined
and, if found matted or hardened, should be replaced.
Bearings, if loose, worn,
pitted or cracked, or if they show signs of being heated,
should also be replaced.
Brushes worn short should be
replaced. Both stationary brushes are Auto-Lite GAS
12. The third or moveable brush is Auto-Lite GAS 13.
Natural wear of the brushes
causes carbon dust to collect on the inside of the generator
and its accumulation will cause unsatisfactory
operation. It will soon mix with the oil that reaches
the interior from the bearings or other sources and form a
gummy paste that will coat itself all around the commutator
end of the body. Clean with gasoline and wipe all
parts.
The commutator should be
free from all oil or dirt. No. .00 sandpaper should be
used in cleaning and should be wiped with a clean rag.
(Never use emery cloth or any other cleaning material.)
Never put lubricants on the commutator or brushes.
The brushes should be free
to move and make good contact with the commutator's polished
surface.
Disassembly
If its surface has been
pitted, the armature should be removed and a slight cut
taken in a lathe across its face. After this, it
should be carefully polished.
1. Remove the machine
mounting clamp from the generator.
2. Remove the inspection
steel band. If the gasket is damaged or broken,
replace it for reassembly.
3. Disconnect the two black
wire leads from the brushes and pull the wires thru the
inspection slots so that they are out of the way.
4. Remove the two long body
screws at the commutator end plate.
5. Tap and pry off the drive
end plate from the other end.
6. Remove the armature and
commutator end plate as a unit.
7. Remove the three screws
and triangle plate and gasket from the commutator end.
8. Remove the flat head
screw and washer on the shaft.
9. Slide the end plate off
the armature, using care not to damage the brushes by
letting them snap off the edge of the commutator.
10. Disconnect the ground
for the field coils at the drive end of the body.
11. Remove the two outside
body screws holding the field magnets and field inside the
body.
12. Remove the field
magnets. If the insulating sheet is worn between the
fields and the body, it should be replaced. This
insulation protects the field center connection from
touching the body or the long body screw passing through the
loop.
13. On the commutator end
plate, push out from the inside the armature end bearing;
this is a slide fit and will drop out from the outside.
14. At the same time push
out the flat washer, felt disc and metal cup.
15. Inspect the bearing; if
loose, burned, or the balls show wear, or if loose on the
armature shaft, replace.
16. Unless the fiber
mountings holding the brush assembly in the end plate are
burned, or the brush anchorages are loose, it is not
necessary to remove this assembly. If the brush
anchors are loose, remove the screws holding it to the
body and replace with a new
assembly, using care not to bend the spring clips bearing on
the "third" brush plate.
17. Check the oil passage
filler in the end plate. It should be free and open.
18. Take the drive end - end
plate. Remove the three screws holding the metal plate
on the inside of the drive end end plate and remove the
plate.
19. Tap out the
bearing from the outside and remove the felt washer and
retaining washer disc. If the bearing is burned,
pitted, worn, or does not fit the armature shaft snugly,
replace.
20. Check the oil
passage in the drive end end plate.
21. If the oil caps on
either drive end are broken, pry out and replace.
Testing the Generator Parts
1. Armature
When the armature is
revolving inside the generator, centrifugal force sometimes
causes the coils to expand and strike the laminations.
Check to be sure no worn spots show on any of the wiring.
Check the segments on the
commutator end. If out of round or any mica insulation
between the segments is higher than the segments themselves,
turn down in a lathe, then cut back the mica insulation so
that it is about 1/32" lower than the copper segments.
If any of the armature
wiring is broken or the insulation is badly burned, replace
with a new armature. Test for shorts and
"open" with a standard "growler".
If the shaft ends are worn,
replace with a new armature.
2. Field Coils
If the field coil insulation
is badly burned or worn, these should be replaced.
To test the field coils,
connect one end to a regular storage battery and complete
the circuit to the other battery terminal through a headlamp
bulb or other 6 volt bulb.
If the lamp lights, it will
indicate that the field coils are okay. If the lamp
does not light, it would indicate an open circuit in one or
both of the coils. If an open circuit is found,
replace with new coils.
Single coil resistance at 6
volts is 5 amps. Both fields at 6 volts - 2.5
amps. Test with a meter.
Assembling the Generator
Both end bearings should be
packed with a neutral grease of high melting point.
All parts should thoroughly cleaned in gasoline. This
does not apply to field coils or wiring.
Brushes should have a
minimum length of 3/8". If not replace GAS 13 on
moveable brush holder. GAS 12 used on stationary holders.
1. If the short insulator
for the wire leading thru the body to the cut-out is loose,
burned or worn, remove and replace with a new insulator.
2. Replace the field coils
and their magnets with the short ground lead from the coils
lining up with the ground hole connection in the body at the
drive end.
3. Slip the looped
insulating sheet under the field coils at the commutator end
so that the long body bolts will be able to pass through the
loop when the two ends are in place.
4. Replace and tighten the
two large screws holding the coils and magnets to the body.
5. Connect the ground (flat
head screw lock washer and nut).
6. Draw the leads from the
cut-out and field coil out through the nearest inspection
slot in the body.
7. Slip the commutator end
of the armature into the end plate, lifting the brush
holders up onto the commutator so as not to scratch it or
ruin the brushes. Replace GAS 13 carbon on moveable
holder; GAS 12 carbons on stationary holders with lettered
side towards screw head.
8. Replace the commutator
end bearing (small) in this order:
(a) Cupped washer (cupped
side facing armature).
(b) Felt washer
(c) Flat washer
(d) Bearing (the side on which it is lettered face away from
armature).
9. Replace the small flat
countersunk washer and screw in the shaft.
10. Slide the armature
through the generator body.
11. Take the drive end end
plate and from the inside replace in the following order:
(a) Cupped washer (cupped
side toward the armature).
(b) Felt washer
(c) Flat washer
(d) Bearing (the side on which
it is lettered face toward the armature).
(e) Large metal plate (cupped
side toward the bearing with small indentation in line with
the oil filler cup on the end plate).
12. Hold the commutator end
plate against the body with shaft end resting against a
raised block so that it cannot slide in the commutator end
plate and damage the brush holder. Then press the
drive end end plate onto the armature shaft lining up the
hole in the end plate with the pin in the body.
13. Replace the two long
body bolts from the commutator end plate to hold both plates
against the body. When the sprocket drive gear is
assembled and tightened, there should be no end play in the
armature but it should turn freely and easily.
14. Replace the triangle
cover on the commutator end and its gasket.
15. If new felt washers have
been used, use enough oil (S.A.E. 10W) in both end caps to
saturate the felts but if the same washers have been used -
use only a few drops of oil.
16. Attach the lead from the
field coil to the moveable brush (through the inspection
slot).
17. Attach the lead from the
cut-out to the positive brush.
18. Inspection band and
gasket can be replaced after the generator has been placed
on the machine and regulated for output.
19. To test: Connect two
leads to a 6 volt battery. Ground one to the
generator. Touch the other to the lead going to the
cut-out. It should "motor" if assembled
properly.
20. Check the wires going to
the brushes to make certain no wire touches the armature or
bears against a brush spring where it can become worn in
use.
The Generator Out-out
The cut-out should have a
gap between its contact points of .025. The gap between the
magnet core and armature should be .030.
Failure of the points to
break without load will cause pitted points, short circuit,
and will discharge the battery and burn out relay coils.
1. Remove from generator
body and disconnect.
2. Pry up the clamping edges of the cover.
3. Polish the contact points and set to .025.
4. Use .00 sandpaper and clean magnet core, contact and
bar. Set to .030.
5. Replace cover, bending over edges, connect and attach to
generator body.
Attaching the Generator to
the Machine
1. Replace the frame
mounting clamp to the generator leaving it loose so that the
generator may be turned or slide either way.
2. Slip the frame bolt
through the clamp, holding the generator in position against
the front frame tube. Assemble plate and felt washers
between chain plate and generator.
3. Slide the generator
toward the generator drive chain plate.
4. Assemble the drive gear
on the shaft using the keyway, and tap into position.
Tighten sprocket nut on shaft.
5. Slip the generator chain
over the drive sprocket and connect
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