Brush maintenance
RESTRICTED
Slip Rings
Stab.
Fig. 24
Isolated
Sector
Stab.
Fig. 25
terminal over the four thicknesses.
Do not cut
the ends of the pigtails. They are cut to exact
length at the
factory.
b. Use no solder
on connections, as solder
destroys the balance of the gyro. Brush should
make a minimum of 85% contact with
the commutator.
This is obtained by
running
in brush
for a few
minutes,
then
scraping
the
high spots (bright
spots) with a
again and recheckr® Straight edged tool. Run in
CAUTION: Scrape very lightiy.
C.
The brush nuts should be turned down to
exactly the same position as before removal.
The
factory adjustment is, with the nut extended, 5/16"
on the stab. gyro.
No change should be made in
this setting to adjust the spring tension on the
brushes.
If the tension
is not
correct with this
adjustment, the cause is a defective spring or
worn brush.
Clean slip rings with #400 aluminum oxide
and polish with crocus cloth. Brushes may be
stoned smooth.
2.
See that brushes have
ecual tension.
Bend
the slip ring brushes
interbs brush
to top of bend.
Brushes must be very smooth at
contact points and spread slightly at slats through
center of brushes.
3.
Brushes must ride
center
of rings and
touch insulation on
either side, and lie flat
against the slip rings.
1.
Remove pits and
burrs with #400 aluminum
oxide paper, by placing
the
#400 aluminum oxide
paper on a flat surface (stabilizer rear inspect-
ion platel and by rubbing
the isolated
sector
across
the paper lengthwise to the sectors. Polish
with crocus cloth or
fine Arkansas stone, polish-
ing or stoning parallei to the sectors.
Use ohmmeter to check for continuity between
sectors; there should be none.
The contact point of the isolated sector con-
shouid have a 1/32 bevel
top and
bottom.
Bevel edges
other
and
should be papallel to each
to the insulation between sectors.
The
contact point must ride
perfectly flat on the sec-
to-s.
Do
not round the point.
The use of the
dental mirror
loupe will detect points that
are not correctly shaped.
ciliate
The point should os-
small amount before contacting a
6-volt sector.
52