Richmond times-dispatch. [volume] (Richmond, Va.) 1914-current, 1917-05-13
s|MPL|F|ED LESSONS ON
PROPER CARE. OF AUTOS
Automatic Cut-OT or Relay In
planned in Detail by Timcs-Dis-
patch Auto Expert.
HOW THE CUT-oTE OPERATES
Purpose OF the Cut-OT Is to Discon-
meet Battery and Generator When
Voltage OF Battery Is Greater Than
That OF the Generator.
LESSON 40. ~.
The Automatic Cut-Uut.

$ Copyright. 1871, by Fred G.. Ciucrrlich
AS WAS shown in The frat lesson on
starting and Lighting" when the en-
CINE is idlo the generator will not be
sending current TO tho battery but
the current from the battery Will flow
10 tho generator. and so. unless some
device, which viii di.conncc, the bat
tory and generator. is used. the bat
terry Will soon be discharged
Tho device used for this purpose is
called nm automatic cut-out." and
sometimes q relay.
Not only must Tho cu,-out he used
when tho engine is Idle, but also when
II IL running slowly, as at the slow
speed tho voltage of tie current. made
b. the generator. will be less than the
voltage Tor prcsSurc) of the battery
and so under this condition the current
would also flow from the battery 10
the generator. and so tho battery be-
come discharged
From the ;lEovc sc sec that the pur-
pose OF tho cut-out is TO d,sconucct the
battery and generator the moment the
voltage OF tho battery Is greater than
the voltage o: the generator. and 10
connect them. the moment the genera
tor voltage is greater than that oc tho
battery.
The cut-out is arranged 10 act a, an
engine speed OF about go revolutions
per minute. or car speed OF about
fifteen miles per hour. Thus you Will
notice that the generator VIII charge
tho battery only at Il car speed greater
than fifteen miles per hour
How the Cut-OT Works.
Let us how tho automatic cut
out operates. Were - current OF cleo
tricity To Tow through coil Is. Fig. /.
in the direction OF the arrows, then
the core = would become magnet
and would draw a piece OF steel TO
it's ends. II 81 current were also made
IN 10 I,yh 4 IN ba Inn
OF tho arrows, the magnetic strength
of tho core would be increased. bu;
should the current fow through in
the reverse direction. then this coil
would act against the coil r, and so
tho core would lose It's magnetism, o;
In other words. tho magnetism created
by II would be absorbed by c. II Is.
on this principle that most cut-outs
operate.
Figure . shows the condition of -
Eosch cut-out when tho generator is
making = current Of higher voltage
than that OF tho ba:tcry. Here YOU
Will notice, By studying tho arrows,
that the current Is flowing in tho same
direction through both coils. ,B and &.
The core is. therefore, a magnet, and
has drawn down the button against
tho spring action and 80 closed tho con-
tacts. Thus the battery and genera
tor arc connected or ''cut in
Fig. : shows the condition When the
generator Voltage Is less than tho bat
terry voltage. Sy studying tic itrroNs
YOU will notice that tn" current NoNt
through the coils Is ana 6 IN opposite
directions. Tho uasuctiziDE action q!
tho ono coil will now ucutrAlizc that OF
the other. and 80 The cor" viii cease
TO be u imagine; aud VIII no longer
draw down :hc button. The contact
points VIII therefore open and ihc
battery and generator be disconnected
on 'tut-out."
Tho position OF The cut-out varies in
different makes OF cara. Sometimes IL
is placed on TOD or on tho side Of tGc
generator. and often 1t is placed ON the
dash.
Should your battery become d's-
charged overnight il may bc duo 10 tho
contact points OF the cut-out sticking.
or 10 tho spring. which pulls them
apart, being broken, loose or weak.
When tho engine is idle Tic contacts
should be opcu.
Failure OF the generator 10 charge
the battery may also be due to the
automatic cGt-out. III this case the
trouble viii he due 10 the contacts not
being pulled together. or TO the con-
tact points being SO burned or pittcd
as 10 mako 4 poor contact. They should
be closed at tho higher engine speeds.
The Voltage Regulator.
The voltage or tho current made by
the generator varies with the speed of
the armHturc, and at very high engine
speed 1t may be so high AS TO do dam
age 10 the battery. 20 prevent This a
device must he put into The circuit
which viii! not permit the voltage TO,
get above 4 certain amount. This de-
vice is called voltage regulator
Voltage regulators wary greatly in
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