Bentley R Type - Fuse Box; Output Regulator and Cut-Out

THn ETBCTRTcAL
SysrBnr. 87
Messrs.
Bentley Motors
(t93t)
Ltd., or one of their
"Special
Retailers".
Emphasis
is
laid
on
this
point,
as cases have arisen of faulty
operation
of the dynamo,
due to
inexpert
fitting
of brushes.
When
it
is necessary
to disconnect
the wires to the
dynamo, care
must be
taken
to ensure their
correct
replacement.
Fuse Box.
The
large
fuse
box
(2, Fig. 42)
carries
the
circuit
{uses. Each
circuit
fuse
is
one strand of
No.
3z
S.W.G. tinned copper
wire.
The small
fuse box
(1
)
carries
the main
fuse; this is
three
strands
of No.
Sz
S.W.G. tinned copper
wire.
Spare
fuse
wire
of
this
gauge
is
provided
in
a special holder within
the
large fuse
box.
Special care must
their holders,
and that
Output Regulator
and Gut-Out.
The output
regulator
and cut-out
are mounted on the front
of the
dashboard,
and are shown
(5,
Fig.
a2).
The
output
regulator
operates
to
control
the
dynamo
output
by
varying
the field
excitation
in
accordance with the load on
the
battery
and
its
state of
charge.
The
operation
of
the regulator
depends upon
the fact
that the
voltage
of
a
battery
varies between certain
fixed limits
according
to
the
state of charge
of the battery,
the voltage being,
of
course,
a
maximum
when the battery is
fully charged,
and a
minimum
when the
battery is fully
discharged.
The regulator
is combined
structurally
with
the cut-out.
The
regulator
and cut-out
are,
however,
electrically separate, employing
separate
armatures,
though
they possess field
systems which are
common
over
a portion
of
the
magnetic
path.
The cut-out
is operated
when
the
dynamo
speed rises high
enough
for
the
dynamo
to
charge
the battery by means of its
shunt
coil
connected
across
the main
terminals
of
the
dynamo. This closes
the cut-out
contacts
and so connects
the
dynamo with the battery,
via
thp regulator
and ammeter,
as
shown in
the wiring
diagram
Fig.
ao).
The series coil
is so connected
that, when carrying
the
charging
current,
it
assists
the
shunt coil
in holding
the
contacts firmly
together.
When
the
dynamo
slows
down, and
its
voltage
falls
below
that of
the
battery,
the current
reverses
through
the
seri"es coil,
and the effect
of
the shunt
wrnding
becomes neutralised,
which results
in
the
contacts
falling
apart.
be taken that
all
fuses
are
gripped
firmly
in
the contacts
are clean and
bright.