<s>
A	O
starter	B-Algorithm
solenoid	I-Algorithm
is	O
an	O
electromagnet	O
which	O
is	O
actuated	O
to	O
engage	O
the	O
starter	O
motor	O
of	O
an	O
internal	O
combustion	O
engine	O
.	O
</s>
<s>
Its	O
primary	O
function	O
is	O
as	O
the	O
actuating	O
coil	O
of	O
a	O
contactor	B-Algorithm
(	O
a	O
relay	O
designed	O
for	O
large	O
electric	O
currents	O
)	O
which	O
connects	O
the	O
battery	B-Algorithm
to	O
the	O
starter	O
motor	O
proper	O
.	O
</s>
<s>
All	O
modern	O
cars	O
also	O
use	O
the	O
starter	B-Algorithm
solenoid	I-Algorithm
to	O
move	O
the	O
starter	O
pinion	O
into	O
engagement	O
with	O
the	O
ring	O
gear	O
of	O
the	O
engine	O
.	O
</s>
<s>
The	O
starter	B-Algorithm
solenoid	I-Algorithm
is	O
sometimes	O
called	O
the	O
starter	B-Algorithm
relay	I-Algorithm
,	O
but	O
many	O
cars	O
reserve	O
that	O
name	O
for	O
a	O
separate	O
relay	O
which	O
supplies	O
power	O
to	O
the	O
starter	B-Algorithm
solenoid	I-Algorithm
.	O
</s>
<s>
In	O
these	O
cases	O
,	O
the	O
ignition	O
switch	O
energizes	O
the	O
starter	B-Algorithm
relay	I-Algorithm
,	O
which	O
energizes	O
the	O
starter	B-Algorithm
solenoid	I-Algorithm
,	O
which	O
energizes	O
the	O
starter	O
motor	O
.	O
</s>
<s>
An	O
idle	O
starter	B-Algorithm
solenoid	I-Algorithm
can	O
receive	O
a	O
large	O
electric	O
current	O
from	O
the	O
car	B-Algorithm
battery	I-Algorithm
and	O
a	O
small	O
electric	O
current	O
from	O
the	O
ignition	O
switch	O
.	O
</s>
<s>
When	O
the	O
ignition	O
switch	O
is	O
turned	O
on	O
,	O
a	O
small	O
electric	O
current	O
is	O
sent	O
through	O
the	O
starter	B-Algorithm
solenoid	I-Algorithm
.	O
</s>
<s>
This	O
causes	O
the	O
starter	B-Algorithm
solenoid	I-Algorithm
to	O
close	O
a	O
pair	O
of	O
heavy	O
contacts	O
,	O
thus	O
relaying	O
a	O
large	O
electric	O
current	O
through	O
the	O
starter	O
motor	O
,	O
which	O
in	O
turn	O
sets	O
the	O
engine	O
in	O
motion	O
.	O
</s>
<s>
The	O
starter	O
motor	O
is	O
a	O
series	O
,	O
compound	O
,	O
or	O
permanent	O
magnet	O
type	O
electric	O
motor	O
with	O
a	O
solenoid	B-Algorithm
and	O
solenoid	B-Algorithm
operated	O
switch	O
mounted	O
on	O
it	O
.	O
</s>
<s>
When	O
low-current	O
power	O
from	O
the	O
starting	B-Device
battery	I-Device
is	O
applied	O
to	O
the	O
starter	B-Algorithm
solenoid	I-Algorithm
,	O
usually	O
through	O
a	O
key-operated	O
switch	O
,	O
the	O
solenoid	B-Algorithm
closes	O
high-current	O
contacts	O
for	O
the	O
starter	O
motor	O
and	O
it	O
starts	O
to	O
run	O
.	O
</s>
<s>
Once	O
the	O
engine	O
starts	O
,	O
the	O
key-operated	O
switch	O
is	O
opened	O
and	O
the	O
solenoid	B-Algorithm
opens	O
the	O
contacts	O
to	O
the	O
starter	O
motor	O
.	O
</s>
<s>
All	O
modern	O
starters	O
rely	O
on	O
the	O
solenoid	B-Algorithm
to	O
engage	O
the	O
starter	O
drive	O
with	O
the	O
ring	O
gear	O
of	O
the	O
flywheel	O
.	O
</s>
<s>
When	O
the	O
solenoid	B-Algorithm
is	O
energized	O
,	O
it	O
operates	O
a	O
plunger	O
or	O
lever	O
which	O
forces	O
the	O
pinion	O
into	O
mesh	O
with	O
the	O
ring	O
gear	O
.	O
</s>
<s>
Some	O
older	O
starter	O
designs	O
,	O
such	O
as	O
the	O
Bendix	O
drive	O
,	O
used	O
the	O
rotational	O
inertia	O
of	O
the	O
pinion	O
to	O
force	O
it	O
along	O
a	O
helical	O
groove	O
cut	O
into	O
the	O
starter	O
drive-shaft	O
,	O
and	O
thus	O
no	O
mechanical	O
linkage	O
with	O
the	O
solenoid	B-Algorithm
was	O
required	O
.	O
</s>
<s>
If	O
a	O
starter	B-Algorithm
solenoid	I-Algorithm
receives	O
insufficient	O
power	O
from	O
the	O
battery	B-Algorithm
,	O
it	O
will	O
fail	O
to	O
start	O
the	O
motor	O
,	O
and	O
may	O
produce	O
a	O
rapid	O
clicking	O
sound	O
.	O
</s>
<s>
The	O
lack	O
of	O
power	O
can	O
be	O
caused	O
by	O
a	O
low	O
battery	B-Algorithm
,	O
by	O
corroded	O
or	O
loose	O
connections	O
in	O
the	O
battery	B-Algorithm
cable	O
,	O
or	O
by	O
a	O
damaged	O
positive	O
(	O
red	O
)	O
cable	O
from	O
the	O
battery	B-Algorithm
.	O
</s>
<s>
Any	O
of	O
these	O
problems	O
will	O
result	O
in	O
some	O
,	O
but	O
not	O
enough	O
,	O
power	O
being	O
sent	O
to	O
the	O
solenoid	B-Algorithm
,	O
which	O
means	O
that	O
the	O
solenoid	B-Algorithm
will	O
only	O
begin	O
to	O
push	O
the	O
engagement	O
gear	O
,	O
making	O
the	O
metallic	O
click	O
sound	O
.	O
</s>
