El Paso herald. (El Paso, Tex.) 1901-1931, 1913-12-20
Copyright. 1918. by W. H. Stewart, Jr.
By WILLIAM H. STEWART, Jr.

Motoring Department, The Herald
Kindly advise me of the principle re-
garding the working of a coil where
the current goes when leaving battery,
whether primary or secondary wiring
connect with spark plug, and If same
wires in coil are in any way connected?
John F. Oigard-
The coil is transformer which
steps I'D the voltage of the battery
or generator to a degree that it will
overcome the resistance Of an air gap
or break in the circuit. This gap is
found at the electrodes Of the spark
plug. The six volts produced by the
battery or generator has not sufficient
pressure or force to overcome this re-
sistance and jump the gap It is the
current jumping this gap at the plug,
thereby producing a spark, which ig-
step up or intensity this current suffi-
silently, a transformer or induction
coil is used The coil is made up of a
bundle of soft iron wires constituting
the core, and about this is a winding
Of a number of turns Of coarse insu-
lated wire. This is called the primary
winding.
Outside of this primary wire is
wound a great number of turns of fine
insulated wire, called the secondary.
The secondary winding of the coil is
not connected in any way to the pri-
mary winding except that it may be
grounded on the same ground wire. One
end Of the primary wire is led to the
battery, the other is grounded. Like
wise. the other side Of battery is
grounded. This practically constitutes
the primary circuit Likewise one end
of the secondary is led to the spark
plug, and the other end is grounded.
This constitutes the secondary circuit,
in that the current passing through the
plug is grounded into the engine after
jumping the gap.
In the primary circuit IS attached an
interruption, or vibrator, which autOmat-
ically makes and breaks the primary
the primary winding about the soft
iron core 1t becomes temporarily a
magnet, attracting the vibrator, and
thereby opening the circuit As soon
as the circuit is opened the core loses
its magnetism and the vibrator springs
back, thereby completing the circuit
again. This automatic interruption OF
the primary circuit sets up a powerful
induced current in the secondary wind
ing. This is accomplished by incrcas-
ing and decreasing the magnetic field
through the action of the vibrator. A
condenser is also attached across the
intensifies this action
The induced current set up in the
secondary winding is Of very high pO-
tentiaL and this current is led to the
wires. This high tension current cas-
lily OVercomes the resistance of the
spark gap and the necessary spark or
ignition results. Usually only one end
Of the secondary is led from the coil.
The other end is usually grounded in
side of the coil. IN other words, both
the primary current and the secondary
current have the same ground wire.
This is possible in that the two cur
rents are of a different nature and can
travel over the same wire without in
reference one being a direct current
and the other an alternating current
Motoring Department, The Herald
Would you kindly inform me If wood
alcohol and water mixed evapor2te
equally when used IN automobile radi-
ator2 II not, how can future Filings
be gagged to keep up the proportion you
desire? E. J. D.
The alcohol will evapOrate readily
and leave a weak solution. A can Of
alcohol and water mixed should be
kept on hand for the purpose Of re-
filling the cooling system. By filling
in this manner the solution may be
kept quite uniform. In severe weather
it is advisable to test the solution oc-
casiOnally. A little too much alcohol
will do no serious injury. 1t is more
advisable to have a strong solution