Raytheon Beech Baron E55 - Electric Propeller Deicing

~eechcraft
BARON
55
AND
58
SHOP MANUAL
2.
The
sensing
element in the
heater
is
tempera-
the
inboard
halves
of
the-~ight
engine
prop.
Each ele-
ture
sensitive;
therefor,
the
resistance
will
vary
with
ment
is
heated
for 30
seconds
to
make
a
complete
temperature
change.
Check the
temperature
resis-
cycle
every
two
minutes.
The
ammeter
hand
will
I
I
tance
chart for the
correct
reading.
Refer
to
Figure
is
operating
properly.
The
system
must
not
be
oper-
ated for
more
than
two
minutes
on
the
ground
as a
FUNCTIONAL
CHECK OF THE
precaution
against overheating
of the
iceguard.
After
a
WINDSHIELD HEATER
CONTROLS
5-minute
cooling
period,
the
system
has
cooled
suffi-
ciently
to
permit
the second
operation.
The
timer
NOTE
needs
no
periodic
maintenance. In the
event
of
failure
As the
sense
element
theater)
cools,
the
return
the timer
to
the
installing facility.
resistance
will
drop.
ELECTRIC PROPELLER
DEICER
BRUSH
a.
Check
that the controller
turns
the heater
on as
the
sense
element
resistance
drops
to
328~
3
ohms
REPLACEMENT
(GOODYEAR)
(88"F
to
100"F).
Brush
replacement
is
normally required
after
500
NOTE
hours
of
service.
The
copper-plated
area
of
each
brush indicates its
wear
limitations. To
prevent
the
As the
sense
element
theater)
heats,
the
copper
from
damaging
the
slip ring,
the brushes
must
resistance
will
become
greater.
be
replaced
as
soon
as
the
copper
plating
becomes
b. Checkthatthe controllerturnsthe
heater
off when
visible.
Prior
to
installing
new
brushes,
the
slip
ring
the
sense
element resistance reaches
338Lt
4
ohms
should be
wiped
clean
with
a
paper
towel
or
rag
that
(100"F
to
110"F).
has
been
dampened
with-an Acetone-based
solvent.
ELECTRIC
PROPELLER
DEICING,
Allow
to
air
dry
completely
before
installing
new
I
(GOODYEAR)
brushes. Maintain sufficient clearance
between
the
(Figure 11124)
brush
block and
slip
ring by adjusting
the
floating
lock-
nuts
in the brush
block
bracket
until the brushes
The
propeller
deicer
uses
two
heating
elements
per
extend from
.08
to
.09
inch from the block. Brushes
blade. The timer
applies
current to
the outboard ele-
should
be
aligned
to
move
freely
in the
brush
holder
ment
first and then
to
the
inboard
element. The
cycling
with
the
entire
face
of each brush
making
contact
with
sequence
of the timer
starts
from the
outboard
halves
the
slip ring throughout
360
degrees
of rotation.
This
to
the inboard halves
on
the left
engine
prop,
then
provides
preventive
measures
against arcing, slip ring
completes
the
timer
cycle
with the outboard halves
to
pitting,
and excessive brush
wear.
11-48
815