H
ELECTRICAL
SYSTEM
·SECTION
H
18
CAPACITOR
IGNITION
(MODEL2MC)
ALTERNATI'(E
SYSTEM
The
Lucas
motor
cycle capacitor system has
been
developed
to
enable machines
to
be run
with
or
\yithout
a battery. The rider therefore
has
the
choice
of
running
with
normal
battery
operation
or
running
without
battery
if
desired
(e.g.
competing
in trials
or
other
competitive
events)
and
for
emergency operation in case
of
battery
failure.
Machines
can readily
be
started
without
the
battery
and run
as
normal
with
full
use
of
standard
lighting.
When
stationary, however,
parking
lights
will
not
work
unless
the
battery
is
connected. The capacitor system also has
the
advantage
of
being less critical
with
regard
to
alternator
timing.
Fig.
H23.
Capacitor and spring
The
system utilises the standard
12-volt
battery-coil
ignition equipment
with
the
Zener
Diode
charging regulator
mounted
on' an
efficient
heat sink, plus a spring
mounted
high
capacity
electrolyte capacitor (Model
2MCl.
of
a special shock-resistant type.
H20
The
energy pulses
from
the
alternator
are
stored by the capacitor
to
ensure
that
sufficient
current
flows
through the
ignition
coil
at
the
moment
of
contact
opening,
thus
producing
an
adequate spark
for
starting.
When
running,
the
capacitor also
helps
to
reduce the
D.C.
voltage ripple.
Also
with
this system alternator
timing
is less
critical. Provided the centre
of
the
rotor
and
stator
poles are roughly in line in
the
fully
retarded position
(I.e.
as normal
battery)
emergency
start
condition
which
is
30'
past
magnetic
neutral, satisfactory starting
will
be
obtained. Furthermore any
auto-advance
angle and speed characteristics
may
be
used
and perfect running ignition
performance
achieved.
IDENTIFICATION
OF
CAPACITOR
TERMINALS
The
2MC
capacitor anelectrolyte (polarised)
type
and care
must
be taken
to
see
that
the
correct
wiring connections are made
when
fitting.
Spare Lucar connectors are
supplied
to
assist
in connecting up. Looking
at
the
terminal
end
of
the
unit
it
will
be seen
that
there
are
two
sizes
of
Lucar connector.
The
small
3/
16
in. Lucar is the positive (earth)
terminal
the rivet
of
which
is marked
with
a
spot
of
red paint. The double.! in. Lucar
forms
the
negative terminal.
Fig.
H23
shows
the
spring and capacitor.
The
capacitor
should be positioned
with
its
terminals
pointed
downwards.
When
fitting
the
spring
to
the
capacitor, insert the
capacitor
at
the
widest end
of
the spring and
push
it
down
until the small coil locates in
the
groove
on
the
capacitor body.
STORAGELIFEOFMODEL2MC
CAPACITOR
The
life
of
the
2MC
is very much
affected
by
storage
in
high temperature. The
higher
the
temperature
the
shorter
its shell life.
At
nonnal
temperature
i.e. 20·C. (58·F.)
it
will
have
a
shelf
life of about
18
months.
At
40·C. (86·F.)
about
9 to
12
months. Therefore,
storing
in
a
cool
place will maintain
their
efficiency.
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