Richmond times-dispatch. [volume] (Richmond, Va.) 1914-current, 1919-06-15
S|MPL|F|ED LESSONS IN
CARE or AUTOMOBILE
Expert Describes Current Generator
and Purpose of Device In Charg-
ing Battery.
SOME SOURCES OF TROUBLE
Armaturc and Field Coils VIII Sell
dom Give Trouble, But Commuta-
tor and Brushes May at Times
Cause Lack OF Current.

II the ends or poles of two magnates
he placed near to one another: so that
on son p9 ps is Hsfn % S9f o the ne other
pole to the other great many in
visible lines of magnetism. or. as they
are called. magnetic lines Of force
Now Ii wire were u cut through
thetc magnetic lines in one direction.
SAY Upward. current, Will now in the
wire. Thus. in Fi6. /, the wire 4 will
be cutting upward during one-haif the
rrevolrtion. and 30 the, current will
hah rolution y tnow in the position
OF - VIII be cutting downward. and
The direction Of fow Of The current
alterna'cS a. above We say that ii is an
alternating current.
Sow: IN, The purpose OF the generator
storage battery canno, be charged
with On alternating current, so a
What san he dom. 10 make the cur
u,1t ydireG.% If each end OF the
shown in Fig. >, the brush y. as the
wire and half-rings rcvoivc. Would
siwaya be rubbing against the half.
ward. and the brush L 10 the half.
ring attached 70 tho wire cutting
dS0"nwaGGd Thus tho ,curro1, would
- and in AT tho brush T., and so tho
current in the wire, i would he OF
direct current, or always Moving in
one direction.
tommutator's Function.
The ha!t-rimGs. TO which the ends Of.
Inc ~ wire irr, ars attached. would have to
ieriai. 50 AZ 70 prsven, the 'i brus iiie
catching TO give strength; and to pre-.
vent Dirt OIL. etc. getting between
YOU viii see later, these half-rinEs are
reduced TO small seSmenta OF circles
IN practice These sesments. with the
the commutator.
% course. one loop Of wire: AS shown
4 N at our
q steady enough voltage 10 be prac;i-
Sa!' anu SO number OF loops arranged
~ 4 circle, as shown in Fig - are
,ted Instead OF attaching the ends
ssEm!ent as in F,e. 3. a number o:
more often a lew o. o. i SfS" sdjace en-!
loops are attached to one segment
For mcchanical reasons. and also to
intensity nc current generated. the
oo!s OF wire arc wound on a soft
large number OF discs. or is laminated
nc core with the loops, or winding
.5ou .s''sa nc arn,alure. Figure
eommu ti;nS at Tie riEht.
10 the magnets You have had broug n,
I" your attention TWO kinds o. mag
ets-rarnely, the permanent magnet.
magnet. made OF soft iron. with a coil
OF wire wound about IL. which is :.
;nhaGnei Only when sGurren, is flowing
- 49, y" ''' !"Nl'l - nc OF
ma Enet is used ia practically all the
generators used IN the starting and
lighting systems OF today.
From where can we get the current
which must aow through the wire
wound on this core Why. from the
ar.natpre, as shown in Figure s Here
"ire Is connected TO one Of the
brushes. then wrapped about one core.
men tho other and then returns 10 the
second brush. while separate wires go
out OF the machine 20 the battery
lights. etc. When a portion OF the
current is so shuntcd from the main
Inc. We say that tho generator is
shunt wound. Tho coil OF wire around
the magnets i called the field coil. as
the magnetic nu!d is due TO It,
j stationary dynamos cor genera
iorsD as are used in large power plants
and in some OF tho small generators
used on the automobile. in addition to
the shunt winding as explained above
the main current. before leaving the
nIhchine. Is first made 10 flow through
. few turns OF wire placed on the
Held magnetic. tho field coil this being
IN series with the outside units
Where the field coil has Two " nds one
shunt and the other series, IL is
SAID TO DC ii compound wound.
Interesting Question.
Perhaps question has come 10 you
namely. II the current generated By