Richmond times-dispatch. [volume] (Richmond, Va.) 1914-current, 1918-07-21
.s|MPL|F|ED LESSONS IN
CARE OF AUTOMOBILE
Magnetic aud It's Troubles Told OF
In Language Clear to
Laymen.
AN INTERESTING DESCRIPTION
frederick G. Guerrlich, Expert on
Motor.Driven Vehicles, Answers
Numerous Inquiries From Owners
as to Their Problems.

as to Their Problems.
Copyright. 1918. by Fred. c. Guerrlich)
AUTO LESSON NO. OF.
In the last lesson l explained how
tho current Is generated in the wire
OF the magnetic. This current. how
device must be added to change this
low voltage to the high voltage neces-
sary to have the current burst through
the air gap OF the spark plug. A
means for distributing tho current to
the various plugs must also be fur
n!shed
The earlier nagnetos simply acted
as current generators, which might be
said to replace the battery. With them.
an outside induction coil was neces-
aary. just as II is necessary with the
distributor. or battery system. now 10
! much used. In this case. the wiring
was as shown in Fig. /.
|, In Fig. ], a Is the armature with
\ i,s wire. while b. l.. j Is the Undue
ton coil. and G the interruptor. is
The secondary. or high-tcnsion COLL
and l. the distributor. The action. as
las often been explained, is this: When
current Is flowing through the primary
wire +, the core II vii be magnet!Zcd
but the moment the flow OF the current
is stopped by the opening OF the inter
.uptor points. the core will suddenly
be demagnetized. which will result in
shot OF very high voltage curren.
In the secondary wire *.
OF course, Il would he fine X the
coll could be done away with. The
fact that the immature core is OF the
and that II also has already coil
OF primary wires, suggested TO inren-
tors The idea OF using this armatuyc
core and It's wiring as tho core and
primary wiring OF the coll. in addi-
ton TO having them act as generator.
II this could be done, it would only
be necessary TO wrap the coil OF sec
ondary &ires about the armature. a
study OF the sequence OF the various
actions showed that these actions came
20 as TO make the above entirely prac-
t!cal. Thus the h!gh-tension magnetic,
which has now completely replaced the
iow-tension magnetic was brought out.
In Fig. ., the wiring OF tho high
tension magnetic Is shown. Here the
coll II liz tho primary wire. This starts
a. S. goes around the core. then to
the bar r. From r the current Will
SO through wire l. 10 the intcrruptor.
across the points and then TO the
y
which there are great many turns
OF wire on tho armature. starts at J.
goes through the coil then by way OF
] 10 the collector ring from which II
is collected by the collector brush, and
then passes through the conductor bar
81 10 the distributor. The distributor
viii distribute the current 10 the spark
plugs in the firing order OF the engine.
a comparison OF the wiring OF Fig.
!, with Fig. viii show that the only
difference Is tina, the armature and
coil OF Fig. have been built together
in Fig. 9.
TIE action OF the switch used with
the hish-tcns!on magnetic for stopping
lhe engine. is the reverse OF that Of
practically all other ignit!on systems
With other systems. when u Is desired
TO stop the engine, the switch Is
thrown so as TO break the contact.
while, with the high-tension magnetic,
the switch should make contact. Let
US see why.
tension current Will flow only when
the fow OF the primary current is
suddenly stopped. This is accomplished
by the sudden opening OF the interrupt
TOR points. Now you VIII notice from
lF!g. that the primary current flows
yrom f across the interruptor points
to the groundA Therefore. II we were
Ito run wire from r to a switch and
, thence 10 the ground. when this switch
lis In the contact position there Will
always be passage for the current
10 the ground. whether the interruptor
points open or not. Therefore, the
fow OF the current will not be stopped
with the opening of the interruptor
points. and there Will be no high volt
age or secondary current and no spark.
The action OF the magnetic Is such
high enough 10 jump across the air
gap OF the spark plug. AS there is
a complete circuit for the current when
1t has broken through this spark gap,
the voltage will go no higher. The
greater the air gap. the higher will
have to be the voltage.
Now the amperaGe. or quantity OF
current decreases as the voltage in
creases. Thus the greater the air gap
of the spark plug the less the amper-
age. AS the spark is hotter with
greater amperage. we can also say that
the greater the air gap. the cooler the
spark For this reason the spark-pluG
jpoints should be close together as
1possible without there being danger
of them touching and short-circuiting.
The distance should be between one
sixty-fourth and one-fftieth OF an inch
Because the voltage builds up as
of a spark plug, become so high as
10 burst throl gil the insulat on some
where, possibly on the armature, and
so ruin the magnetic. To prevent this.
all magnctos have a safety spark gap.
This Is simply a connection, cut into
the main secondary wire. as shown in
Fig. 9, In which there is an air gap
q bout twice as great as that OF the
spark plugs when properly set.
Just so long as the spark-plug points
have an air gap less than the safety
spark gap. the current will flow to the
Mugs If, however. wire comes Oft
then the current will burst across the
safety spark gap. and so will do no
harm TO the instrument.
I might say here. that no matter
what your ignition system, never run
the engine with n secondary wire dan
Cling loose. II you have occasion to
run the engine with a spark plug ont.
I've the wire touch some metal part.
7ou will find the safety-spark gap
shout in the position shown. One por-