Honolulu star-bulletin. [volume] (Honolulu [Oahu, Hawaii]) 1912-2010, 1917-05-26

and the cutout contacts will open. The
front lamps take their current through
a special switch whose connections
are such that the resultant magnetic
action of the generator current in the
solenoid is less with the front lamps
on than without them. Hence the cur
rent output of the generator is in
creased when these lamps are turned
on. The switch in the upper left hand
corner, marked N, in Fig. l, is for get
ting the right rate Of current output
from the generator continuously
should conditions demand it.
Solenoid and Mercury Well Control
of Field Resistance.-A number OF
the earlier Delco-systems were
equipped with a regulator known as
the mercury we'll type, A cross sec
ton of one is shown in Fig. 2. This
regulator consists Of a winding, A,
which surrounds the upper end OF
mercury tube, B. Inside this mercury
tube is a plunger tube, c, with a wind
ing of resistance wire, R, about its
lower end. One end of the winding
R. is attached to the cover end Of
the plunger tube and the other end is
connected to the needle, n, carried in
the center Of the lower end of the
tube.
The lower portion OF the mercury
tube is divided by an insulating tube
into two concentric compartments, the
plunger tube being partly immersed in
the outer compartment and the lower
end of the needle, n, in the inner COM
partment. The space in the mercury
tube above the mercury is filled with
a special kind of oil, which serves the
double purpose of protecting the mer-
curry from oxidation and of lubrf
eating the plunger tube. The whole
device is supported by a bracket, D.
The terminals of the winding A are
connected to the two wires leading
from the generator brushes, and as
the voltage of the generator increases
the current in the winding increases.
Hence there is an increase in the mag
retic pull on the iron plunger tube c.
+ As the lower end of the plunger tube
is withdrawn from the mercury, due
to the magnetic pull of the winding
A, more resistance is inserted in series
with the shunt field winding OF the
generator, as the field current must
now pass through a greater length o.
the wire in the winding A, in passing
from the needle, n, to the mercury In
the outside mercury we'll. With this
! increase in resistance in the field
winding there is a smaller field cur
| rent for a given terminal voltage.
| Hence the terminal voltage of the
generator does not increase as rapid
! ~ as it would If no resistance were
inserted in series with the field wind
| ing.
| AS the charging of the battery con-
! tinues the voltage of the system in
creases, and the magnetic pull pro-
duced by the winding, A, increases,
causing more resistance to be inserted
| il the field circuit and thus preventing
an excessive charging current while
the battery is approaching condition
of complete discharge. With a de-
crease in speed of the generator there
viii be a decrease in the generated
voltage, thus causing a decrease in
the magnetic pull produced by the cur
rent in the winding. A, and hence a
| decrease In the resistance of the field
fcircuit, which prevents the voltage de-
crossing as rapidly as it would other.
Wise 49, = y aEfg go. -.