Mooney M20M - Page 145

MOONEY AIRCRAFT
CORPORATION
M20M
SERVICE AND
MAINTENANCE MANUAL
30-6600
BRUSH TO
SLIP
RING
Refer
to
manufacturer’s
Service
Data,
McCauley
RESISTANCE
TEST
Manual
No.
830415,
Section
6.5.2,
for
brush
To
check
for
incorrect ~sistance
or
presence
of
a
short
replacement
and
brush
to
slip ring
alignment.
or
open
circuit
at
brush-to-slip
ring
contact,
disconnect
30-69-00
ALIGNMENT
OF
SLIP
RING
harness
at
timer
and
check resistance
from
each
De-leer circuit
lead,
Terminal
C,
to
ground
with
a
low
To
check
alignment
of
slip
ring
assembly,
securely
range
ohmmeter.
If resultant
readings
are
not
1.55
to
attach
a
dial
indicator
to
engine
and
place
pointer
on
a
1.78
ohms,
disconnect De-leer lead
straps
to
measure
slip
ring
(see Figure 30-4).
Grasp propeller
blade
and
heater resistance
individually.
Individual
boot
rotate
it
slowly,
noting
any
deviation
of
slip
ring
from
a
resistance
should
measure
between
4.58
and
5.26
7RUE"
plate
as
indicated
on
dial
indicator. Check
that
ohms.
If
readings
in
first
check
are
not
within
accepted
total run-out does
not
exceed
0.008
inch
total
indicator
limits but those in second
check
are,
the trouble
is
reading
CTIR).
probably
in
brush-to-slip
ring
area.
If
readings
in
CAUTION
second
check
are
also
off,
the De-leer
concerned
is
Due
to
loose
fit
of
some
propeller
thrust
damaged
and
must
be
replaced.
bearings,
a
considerable
error
may
be induced
30-67-00 BRUSH
ASSEMBLY
in
readings
by pushing
in
or
pulling
out
on
RESISTANCE
CHECK
propeller
while
rotating
it. Care
must
be taken
to exert
a
uniform
push
or
pull
on
propeller
to
To
check
for
an
open
circuit,
a
short,
or
high
resistance
hold this
error
to
a
minimum.
in brush
assembly,
measure
resistance from
face
of
brush
to
its
terminal
studs
with
a
low
range
ohmmeter.
CAUTION
If this
resistance
measures
over
0.013
ohms,
locate
Do
not,
under
any
circumstances,
attempt
to
and
repair
cause
of excessive resistance.
If
resistance
correct run-out
of
slip
rings
by
shimming
is
infinite,
locate and
correct
the
open
circuit
or
ground,
assembly
or
changing torque
of
mounting
or
else
replace
brush
assembly.
Check
resistance
screws or
bolts.
between
the
three
terminal studs.
This
resistance
if
slip
ring
run-out
is within limits
specified,
no
should
not
be less than S
megohms,
corrective
action
is
required,
If it is
not
within
limits,
30-68´•00 BRUSH
BLOCK
ASSEMBLY
check for dirt
on
ring
gear
mounting
surfaces; clean,
REPAIR
and
recheck
alignment.
If
run-out
is
still
out of
tolerance,
refer
to
manufacturer’s
service data
for
Refer
to
manufacturer’s
Service
Data,
McCauley
machining
procedures
or
return
the
slip
ring assembly
Manual No.
830415,
Section
6.5.1,
for
this
procedure,
to
manufacturer.
30-6801 -BRUSH
REPLACEMENTIAUGNMENT
30-70-00
-SERVICING/CLEANING
Thoroughly
cleaning
the
slip
ring
area
with
<P~
MEK
or
standard
engine
degreaser
on a
routine
basis
is recommended.
Keeping
the
brushes
free
of
dirt,
oil,
grease
and
carbon
buikl-up
will
prevent
thosecontaminants from
being
transferred
to
the
slip
ring.
ALIGNMENT
OF
SLIP RING FIGURE 30-3
30-66-00
4-99
20
OLDWILLWAYNE