- -
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Rolfs-Royce &
Bentley-------
Air
Conditioning
System
Manual
Providing
Recirculated
air
of
increased
temperature.
3rd' clockwise
Water
Tap
Blower
Motor
OPEN
FULL
SPEED
Providing
Recirculated
air
of
maximum
temperature.
1st
anti-clockwise
Water
Tap
..
Compressor
Blower
Motor
CLOSED
OPERATING
MEDIUM
SPEED
Providing
Cold recirculated air entering the
car
via
the
lower
evaporator
matrix.
2nd anti-clockwise
Water
Tap
..
Compressor
Blower
Motor
CLOSED
OPERATING
FULL
SPEED
Providing
Recirculated
air
of
minimum
temperature
entering
the
car
via
the
lower
evaporator matrix.
THERMOSTATIC SWITCHES
The Cartridge
Thermostat
consists
of
two
silver contacts. attached to, but insulated
from,
two special nickel steel members
of
low expansion
co~fficient, mounted
under
tension in a seamless
drawn brass tubular shell.
Changes in
temperature
cause
the
shell
to
expand
or
contract, subjecting the steel contact
supports
to
changes
of
tension, thereby causing
the contacts
to
•make'
or
'break'.
Two
thermostats
are
incorporated
in the
system,
each
controlling
one
of
the solenoid
valves which regulate the supply
of
refrigerant to
the evaporator matrices. When the temperature
of
the
air
leaving the matrices falls to a level a little
above freezing point; the flow
of
refrigerant
is
cut
off,
in
order
to
prevent
the
matrices becoming
blocked by ice formation.
Adjustment
of
the cut-off
point
is effected by
varying
the
tension
in
the
nickel steel members
by means
of
a vernier screw which is accessible
when the thermostat rubber end cover
is
removed
(see Fig.
5).
Setting
the
switch
should
be
attempted
only
with the aid
of
a power source and indicator light.
Random
operation
of
the setting screw, without
positive indication
of
the 'make'
or
'break'
of
the
contacts, may strain the internal assembly.
A locking clamp is provided to ensure that the
setting
remains
undisturbed
by vibrations,
and
should be adjusted so that the vernier screw may
be
turned
without
undue
strain; this
should
be
carried
out
before final adjustment
of
the switch,
since tightening
of
the locking screw after adjust-
ment may alter the setting.
Care
should
be exercised in handling the
thermostat, since it
is
the outside shell which
forms the operating element
and
distortion
of
this
shell may affect the operation.
ACTUATORS
The heater flap, evaporator
flap
and
heater water
tap
actuators
are
identical
units,
consisting
of
a
small electric motor driving through a reduction
gear train. The shaft carrying the final gear in the
train also carries a
contact
disc which has a
portion removed; this disc conveys current to the
motor
via
any
one
of
four fixed
contacts,
when
the
circuit
is
completed
by
the
upper
or
lower
airstream switch action.
Operation
of
the motor causes the disc to
rotate
until the
gap
in the disc reaches
the
con-
tact, thus breaking the circuit.
Attached to the
end
of
each actuator gear shaft
is
a crank lever. These crank levers are connected
by
links
to
sfmilar levers fixed
to
the
water
tap
spindle
and
to
extensions
of
the
heater and
evaporator
flap spindles. The extension spindles
protrude through the actuator mounting platform,
and
flexible couplings transmit the drive, through
holes
in
the valance, to the flap spindles. Rubber
sleeves are provided under the wing to protect the
flap driving mechanism.
Page9
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