Honolulu star-bulletin. [volume] (Honolulu [Oahu, Hawaii]) 1912-2010, 1917-07-21
SPECIALISTS DESCRIBE THE CONSTRUCTION OF SWITCHES AS
FOUND IN THE ELECTRICAL EQUIPMENT OF THE AUTOMOBILE
10y Special Permission from Motor
A0S)


completing the circuit just Gs valve
In hydraulic circuit or pipe affol de
. means Of opening and closing the
circuit of which the pipe is part
Electrical switcacs assume many dif-
ferent forms and sizes, depending
upon the service for which they ara
designed primarily, which places GER,
tain requirements upon the switch IN
order that It operate successfully.
Thus, q switch that IL TO carry
heavy, current must be constructed
with large contact surfaces in order
that the resistance Of these contacts
be low; the surfaces Of the materials
which come into contact with each
other must be smooth and should be
In actual contact over as large an area
as possible; the operation OF thu
switch should be as positive as posi-
BILE, and all connecting terminals and
parts should be or ample size to meet
the ordinary requirements to be i'm.
posed on the switch when in actual
service.
In q great many cases certain parts
Of the switch are made up Of a number
Of thin pieces Of copper instead of one
gives much better contact and also a
surer contact in the majority of cases.
A switch Of this kind is said to be
laminated. The selection Of the ma.
terial to be used at the breaking points
Of the switch will depend upon how
severe an arc is likely to form and
the probable destruction or damage
resulting from such an arc.
The breaking contacts are in some
cases made OF carbon, hut in the great
majority of cases metal is used
Switches that are TO carry small cur
rent, such as those ordinarily found in
the lighting circuits Of motor car.
are much smaller and require smaller
contacts and smaller parts as whole,
but their operation should be quite
positive to reduce the tendency for
arcs 70 form at the points OF contact
when these contacts are being made
and broken In the operation Of the
switch.
Mpst Stand Pressure ,~aE'
II d switch Is TO be used IN Q high |
pressure circuit, such as the secondary |
circuit Of "a Induction OF ignition COT,
Il must 30 constructed In such ssoman-
i1er and OF such materials that I'll
easily VIII stand the electrical press
IRE to which ii WIN be subjected un..
der all ordinary working conditions.
The construction Of any switch Is In.
flpenced greatly by the location i'll
which II II 10 be mounted and the
manner 10 be employed in operating
the switch. 49,. esssss lsgss
Quite often switch Is used to
change tho connection Of the various
elements Of circuit rather than to
serve as means merely OF opening |
and closing the circuit A good ex.
ample OF this requirement, as imposed
upon q switch, IL found In those sys-
TENS where the connections Of the var |
ious sections OF the battery are chang. |
ed from a multiple connection while |
the batteries are being charged 70 \ |
series connection when the batteries |
are being used IN operating the start
ing motor.
In some cases q switch Is introduced
mo circuit merely for the purpose of |
reversing the connection Of certain
mart or the circuit with reference to
some other part Thus, in certain ignf-f
ton systems we find what commonly
is called polarity switch. its purpose
beine 10 reverse the connections of the
interrupter points with respect 70 the
battery or generator in order that the
wasting away Of the two interrupted
points may be eQualized. II the direc-
ton Of the current through an inter-
rupter remains nnchsn,sed in direction
there WIN be quite Q difference in the
degree to which the two contact points
are worn away. The metal naturally
tends to travel In the direction of the
current, and as result there IL much
ereater wasting away Of the positive
contact than there IL Of the negative i
contact. An inspection Of q set Of con-
facts that have been In service for
some time win convince you OF this
fact
Al single pole switch IL one In which
provision Is made for opening the cleo.
frical circuit IN which the switch Is
connected at one point only. An ex.l
ample OF switch Of this kind is
shown diagrammatically IN Figure /.
The positive terminal Of the battery is
grounded IN this case and the starting
motor and its series field winding are
connected permanently In series to the
pOSltlNe OF EfOuuuSu SSIuual Oh Inc Il
battery. The starting switch Is intro
fiuced In the lead connecting the mega.
tive terminal Of the battery and one
terminal OF the armatrre of the start
lng motor. The lighting switches In
this figure are also single pole and
their connections are very similar to
those OF the starting switch. Current
for the lights flows through the series
held of the generator and serves to
raise its voltage, which increase its
output the required amount to take
care Of the lamps when they are turned
on. $50 - f.
A two pole switch Is one provided
with two sets Of contacts. Two pole
switches may be so connected that one
set Of contacts Is introduced in one
circuit and the remaining set in an.
cher circuit, which really amounts to
two single pole switches mechanically
connected together, and both circuits
are operated at the same time. mi
The great majority Of cases, however.