Bentley R Type - Switchbox; Ammeter

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ErrcrRrcAl
Sysrru.
89
Switchbox,
Mounted on the instrument panel,
this
unit
includes:-
(a)
Master
switch and lamp
switch
combined.
(b)
Ignition
switch.
(c)
Push-button switch for
the starter
motor.
(d)
A
lock which
can be locked
and the key
withdrawn
either:-
r.
When the
master
switch is in
the
rlOfftt
position;
or,
z.
When
the
master
switch is in
the
r(P.L."
(parking
lights)
position.
No
attempt
must be
made
to lock
the
switch in
other
positions.
With
the
master
switch in
the
rrOfitt
position,
all
accessories
and
liglrting circuits,
with the
exception
of
the
roof
lamp,
are rendered
inoperative.
l\{ovement
of this
master
switch
to
the
rrOnt,
position
renders these accessories
available.
The
various
combinations
controlled
are
clearlv
indicated,
as
follows:-
Ofr.-All
circuits
off
except
for
roof
lamp.
On.-Accessories
available.
S. and T,-Side
and tail
lamps
on and
accessories available"
H.,
S. and
T.-Head,
side and
tail lamps on
and accessories
available.
P,L.-((Parl<ing
Lights", side,
tail and roof lamps
on. (No reading
is
shown on
the
ammeter
and all
other accessories are
"off
".)
A
separate switch is provided
for
the
ignition,
marked
trOnt'
and
t'Off".
Normally,
this switch can be
left
in
the
ttOnt'
position,
and
the
switching to
start the engine
can be
carried out on the
master
switch.
No independent
charge
position
is
provided
owing
to the
presence
of
the output regulator.
Whenever the
master
switch
is
on, connections
are
made
which
cause
the dynamo
to charge
the
battery
through
the
regulator,
as
previously
described.
Operation
of
the
push-button
switch for the starter
motor
completes
a
relay
circuit,
which
in
turn
causes the main
starter switch to
close.
Amm'eter.
The ammeter
is
an
instrument
with
a central zero
and
3o-ampere
range,
a
needle deflection indicating
Charge
or Discharge.
As
already explained
]rnder
"Outpu!
Iegulator",
th9 charge
rate
varies
in accordance
with the
state
of the battery.
Consequently,
no
alarm
need
be felt
if
the
charge
indicated
on the ammeter
is quite
small,
especially
after a considerable
period
of running with no
extra
consuming
apparatus,
such
as
lamps,
in
use.