Commutator maintenance
RESTRICTED
a.
Speed of
Sight Gyro
Replace-
ment of
Carbon
Brushes
f.
be
taken or the commutator may be
tapered
or hollowed.
Always
check
make sure
the commutator is not
out of "round".
If it is tapered or
hollow in spots, the commutator must
be turned down on a lathe; otherwise
the gyro would be out of balance and
the low spots would cause arcing and
pitting of the commutator.
CAUTION:
Never use an abrasive
the commutator while itis
installed in the gyro case.
Some of the abrasive will
be deposited on the bear-
ings and
serious damage to
the bearings
will result.
When an abrasive is used
on a
commutator, the com-
mutator should be rotat-
ing on its own bearings
in a lathe.
After
abrasive has
been used
the commutator,
always remove
burrs between
the segments with
aluminum
#400
oxide paper,
or a pointed
stick, and clean with
a white cloth
moistened with carbon tet.
If the commutator is pitted it should
be turned down in a lathe on its own
bearings by an experienced machinist.
(This is a depot or factory.job.)
If the commutator is worn, in
i lizer, so that correct gyro speed
cannot be obtained,or if proper pre-
cession is impossible,
report
the
trouble and await disposition.
1. The sight gyro turns approximately 7800 plus
or minus 250
r.p.m. when
operating on 13.5 volts
or 26 volts.
brushes
will be replaced when 1/4" is
their length (as compared to a new one).
Installation
of new
brushes.
Place spr-
and plug on pigtail: fold back 1/21
to
an
on
the
the
sta-
Carbon
worn
from
carbon
a.
Check
for
fit
in
tube.
ing
164