Piper Cherokee Six - Page 569

PIPER
CHEROKEE
SIX
SERVICE
MANUAL
10-27c.
ALTERNATOR
NOMENCLATURE.
a.
Bearings:
These
units
have
a
sealed
ball
bearing
at
the
drive
end
and
a
two-piece
roller
bearing
at
the
slip
ring
end.
The
inner
race
is
pressed
onto
the
rotor
shaft
and
the
rest
of
the
bearing
is
in
the
slip
ring
end
head.
When
the
unit
is
assembled,
the
inner
race
aligns
with
the
bearing.
When
the
bearing
is
replaced,
the
new
inner
race
must
be
installed
on
the
rotor
shaft.
b.
Lubrication:
The
slip
ring
end
bearing
should
be
lubricated
whenever
the
alternator
is
disassembled.
The
bearing
should
be
thoroughly
cleaned
and
repacked
with
Shell
Alvania
No.
2
or
an
equivalent
bearing
lubricant.
The
cavity
behind
the
bearing
should
be
packed
one-third
to
one-half
full
with
the
same
lubricant.
c.
Brushes:
These
units
have
a
separate
brush
holder
assembly
that
is
installed
after
the
alternator
has
been
assembled.
The
brush
holder
has
a
small
hole
that
intersects
the
brush
cavities.
Use
a
pin
or
a
piece
of
wire,
as
shown
in
Figure
10-24m
to
hold
the
brushes
in
the
holder
during
assembly.
Remove
the
pin
after
the
brush
holder
retaining
screws
have
been
tightened.
Make
a
continuity
check
to
be
sure
the
brushes
are
seated
against
the
slip
rings.
d.
Drive
Pulley:
Torque
the
drive
pulley
retaining
nut
to
35
foot
pounds.
10-27d.
ALTERNATOR
SERVICE
PRECAUTIONS.
Since
the
alternator
and
regulator
are
designed
for
use
on
only
one
polarity
system,
the
following
precautions
must
be
observed
when
testing
or
servicing
the
electrical
system.
Failure
to
observe
these
precautions
will
result
in
serious
damage
to
the
electrical
equipment.
a.
Disconnect
the
battery
before
connecting
or
disconnecting
test
instruments
(except
voltmeter)
or
before
removing
or
replacing
any
unit
or
wiring.
Accidental
grounding
or
shorting
at
the
regulator.
alternator,
ammeter
or
accessories.
will
cause
severe
damage
to
the
units
and/or
wiring.
b.
The
output
lead
must
not
be
removed
from
the
alternator
hile
the
rotor
winding
is
energized
and
the
alternator
is
operating
c.
Do
not
attempt
to
polarize
the
alternator.
No
polarization
is
required.
Any
attempt
to
do
so
may
result
in
damage
to
the
alternator,
regulator
or
circuits.
d.
Grounding
of
the
alternator
output
terminal
may
damage
the
alternator
and/or
circuit
and
components.
e.
Reversed
battery
connections
may
damage
the
rectifiers,
wiring
or
other
components
of
the
charging
system.
Battery
polarity
should
be
checked
with
a
voltmeter
before
connecting
the
battery.
Most
aircraft
are
negative
ground.
f.
If
a
booster
battery
or
fast
charger
is
used,
its
polarity
must
be
connected
correctly
to
prevent
damage
to
the
electrical
system
components.
10-27e.
DESCRIPTION
OF
ALTERNATOR.
(Refer
to
Figure
10-24a.)
The
principal
components
of
the
alternator
are
the
brush
holder
assembly
(1),
the
slip
ring
end
head
(2),
the
rectifiers
(3),
the
stator
(4),
the
rotor
(5)
and
the
drive
end
head
(6).
a.
The
brush
and
holder
assembly
contains
two
brushes,
two
brush
springs,
a
brush
holder
and
insulator.
One
brush
is
connected
to
a
terminal
stud
and
is
insulated
from
ground.
The
other
brush
is
connected
to
ground
through
the
brush
holder.
The
brush
and
holder
assembly
can
easily
be
removed
for
inspection
or
brush
replacement
purposes.
Revised:
11
4
83
ELECTRICAL
SYSTEM
3B17