The Washington times., 1922-03-11
||N7R|CAC|ES Of
|STARTERkNOWN
To SCAN I FEW
George Dacy Explains What
Happens When You "Stsp
on t." ...s

'oPPobo SN'S' wv
on It."
When the average motorist steps
on his starter non-harmonic purr
and whine of the aroused current
barks forth. action is melted In the
engine. the fly-wheel begins to turn,
the cylinders ply backward and for
ward and the engine picks up power
as IL warns. says George II. Dacy
in American Motorist."
The knowledge Of the most OF us
concerning the why, when and where
fore of battery circuits, current and
voltage ends right there. Either the
engine starts or she does not start
after we pummel the starter few
times with our brogans. After we
exhaust our patience and vocabu-
larry on some refractory starter, ten
times out of eleven we give up the
ghost and telephone for the trouble
wagon or call in the aid Of the auto
mobile dealer In the next block who
sold US the car.
The automotive engineers and cleo
trical experts OF the United States
Bureau OF Standards have recently
been conducting some interesting and
invaluable Investigations In studying
the demands upon starting and light
ing batteries in the operation OF varf-
GUS types of automobiles. Perform
ance tests have been made OF the
batteries as they were operated In
automobiles which were In average
running condition and In daily use.
The ordinary devices for measuring
| the current and voltages of these bat
| teries were not satisfactory for ex-
periments of this type because the
data resulting from their use were
| not dependable on account Of the
| rapidly fluctuating values OF these
quantities. On this account, the
| Government experts used oscillo-
| graph records for measuring the In
Simultaneous values Of current and
voltage.
Is Photographed.
| A three-element, movina-coil type
| Of oscillograph was used. Where II
was desired to obtain records for per-
iods of long duration, the ordinary
film drum was replaced by a camera
OF special construction in which
bromide paper in rolls 100 feet long
was used. When making a record"
remarked DR.. G. w. Vinal who had
| charge OF these tests, the sensi-
tized paper was wound upon a drum
| in the lower end of the camera after
| having passed the oscillograph slot
| through which the recording images
were projected. One of the elements
was used to record the voltage at
the terminals of the batteries, an
] other the current through the bat
\ teries, another the current through
the battery circuit, and the third, the
| xx,kt faI - n.
half-second ticks Of a chronometer.
The camera was so adjusted that
the paper moved at velocity which
ranged from two to seven centime-
ters a second.
N AS a rule the initial starting
current does not decrease in the
same proportion as the operating
current when the temperature is in
reased. This indicates that the ini-
ial current which the battery must
supply depends more on the inertia
of the system than on the tempera-
ture Of the engine. The average
operating current at so degrees Cen.
tigrade is practically the same as the
current at. n degrees Centigrade.
Slightly more power Is required to
start the system when the throttle ID
closed although the average operat.
ing power is less II the speed re.
mains constant. Experts believe
that this results from the objects
produced by the greater compress.
sion In the cylinders when the throt.
tie Is open. The power required
TO overcome compression is practi-
cally constant, irrespective of the
temperature, provided the throttle
opening is fixed.
| How Power Is Spent.
The Government engineers state
hat the power furnished by the
average automobile battery is ex.
pended in several ways: () A
small portion of the power is used
up in the starter itself; (D a second
part Is expended in compressing the
gas within the cylinders: (3) another
fraction of the power is used up in
overcoming engine friction which
varies with the speed and the lubri.
cation: while ~. the remainder OF
he power is used for ignition on
some types of cars. The amount of
power which the battery furnishes
may be obtained for any instant by
multiplying the instantaneous val.
ues OF current and voltage. II this
product Is also multiplied by an in.
crement of time, the total energy
or work done by the battery during
that instant of time may be ob.
! tained.
Other interesting data has resuit.
cd from these novel tests. For ex.
ample, IL has been determined dafir