The Winslow mail., 1925-04-28
What Your Ammeter
Tells You
BY JACK COUSINS.

The ammeter, least understood
dial on the instrument board of a
motor car, is in many ways the
most important.
Few automobile owners, however,
understand the story the ammeter
tells as the miles fly by. The am
meter is the guardian of the whole
electrical system of the car, par
ticularly during the extreme of win
ter cold and summer heat, and is
connected to every bit of electrical
apparatus with the sole exception
of the starting motor.
If you get acquainted with
the ammeter it will tell you at a
glance whether or not the whole
system is functioning properly. 1t
will tell you if one of the head
lights is out; it will tell you if
there is a short circuit in the line;
it will warn you the moment the
generator fails to function. An I'M
derstanding glance at the ammeter
every twenty miles or so is a trou-
BILE saver of great Importance.
When the motor is started, and
everything is working properly, the
little hand moves over to certain
spot on the charging side and there
it invariably restS-varying in loca-
ton with the speed of the car
until something goes wrong IN the
electrical system. If one of the
headlights goes out the ammeter
shows a slight increase in the
charging rate; if the generator
fails to function for any reason, the
hand swings away over to the dis
charge side and the driver knows
that the whole load is being carried
by the battery.
The ammeter never shows the
full flow of electricity from the gen
orator, but it does indicate the
amount of electricity that is flow
ing into or out of the battery,
hence the Importance of the tell
tale current indicator and it's ability
to tell what is going on all along
the line.
The laymen might ask why it is
important to know the exact min
ute the generator ceases to func-
ton as long as the car will keep on
running with the current from the
battery. One important reason is
that if the generator fails due to
broken leads in or outside, it
should be given immediate atten-
ton or it will burn out and entail
considerable expense for repairs. II
he also knew that fully charged
battery would turn his engine over
for fifteen minutes in summer, but
for only five minutes or less when
the temperature is at zero, the am
meter tip might also induce him to
crank the car by hand and thus
conserve the energy of the battery.
The generator is the whole
source of supply of electricity and
it keeps the entire system in opera
ton but it requires little if any
attention from the driver. 1t is i'm
portant to know that the electrical
output of the generator may be
varied on most cars by what is
known as the third-brush adjust
ment, for the car consumes more
electricity in cold weather than it
does in warm and the generator
should be adjusted accordingly by
one who is experienced in doing
this kind of work.
It is easy to know when generator
adjustment is required, for !, the
battery will tell you all about it.
Give your battery a hydrometer
test every two weeks. If you find
the battery fully chraged and re-
curing only a little distilled water,
everything is all right. If at the
end of successive two weeks pc
RODS you find the battery persist
emily out of water. it is an indica-
ton that the generator is supply
ing too muchI electricity and if al
lowed to continue will result in
serious damage to the battery. If,
, on the other hand, you find the bat
terry persistently undercharged, the
generator should be adjusted to
supply more current.
1t is important for the driver to
follow instructions carefully when
adjusting the gap on his spark
plugs. A high voltage is required
to make the spark jump the gap,
and the wider the gap the higher
the voltage required. However, if
the gap is widened the voltage is
automatically increased, and if it
goes high enough will cause fail
ure in the ignition coil and will re-
quire a new unit, which is rather
expensive.
! Many drivers, and not a few me-
chanics, have found that an engine