The Black Hills union and western stock review. [volume] (Rapid City, S.D.) 1904-19??, 1906-03-02

ing IS very important consideration IN the
design Of mill may 5e exemplifed by the
following figures. A two inch wrought iron
shaft twenty five hundred feet long without
pulleys and supported by the number Of
bearings required in good practice, would
twist off, if subjected to any load above
mere friction of bearings. A three inch
shaft would do the same at $3.50 feet and
four inch one at 5000 feet.
Kent gives power losses due to belted
shafting in number Of New England cot
ton mills as varying from % to 80 per cent
of total load. What must the loss be in
some Of our mills where the conditions are
the worst possible; where often the manage
ment can see no method Of increasing net
earnings, other than an increased per cent
of extraction or reduction in the price Of
labor, not cost Of same; disregarding wholly
other losses which 60 on continuously, due
to antiquated methods and machines.
The mill builder and operator Of the west
might, and they have, to certain extent
: learned'a valuable lesson from the manu-
facturer of the east where, in a measure,
the success Of an enterprise, depending upon
their being able to make an article cheaper
than their neighbor, has led to extreme
economy of power used i. 9. by the appli-
cation of the electric motor to individual
machines as driving power. In most of
our large modern manufacturing plants,
belts and shafting have almost disappeared
while conditions in our ore mills are not
exactly parallel to those in manufactures,
they are similar in a degree in that there are
number of machines in all mills which run
internationally and for this class of machine
the electric motor is the only economical
driver. With it, when work ceases, the con-
sumption of power ceases, which is not the
case with belt driven machines, where there
is always certain amount of idle shafting
running.
The first factor in favor of electrical
transmission is the reduced cost of building;
for to large extent the heavy frame work
required, where shafting is to be used, can
be dispensed with
Direct coupling, however, is not feas-
ible in all classes of ore grinding machinery
such as rolls for instance, which would
necessitate the use of gear, and this is not
advisable; but for most machines about
mill, motors could be obtained suitable for
direct driving, and mills so driven would be
far in advance of the belt driven mill in
point of power consumed.
One great advantage Of individual drive
is that when It is necessary to shut off one
10 :,,lo
ming Of the rest, thus only partly ceasing
work, while with belt driven system you
must stop altogether.
In cases where the same company is
unity to each other, there is fine field for
he use of electricity as a motive power; for
instead of number of smaller isolated
steam plants, one large central plant should
be built to furnish the entire power, thereby
reducing the cost of running, through re-
duced labor costs, insurance, capital tied up
and most of.all by increased efficiency of
entire system. 80
At mines and'mills remote from railroad
where wood is net available as fuel, great
I saving in cost Of power productio Gamble
made by installing the plant at the railroad
and shipping the goal over an electric wire
instead Of on wagons.
Good modern electrical motors, are about
as reliable pieces Of machinery as anything
in e mechanical way can be made, They
will run continuously with but the slightest
attention, are made almost dust and water
proof, respond Instantly to demand for
increased power and as readily accommodate
themselves to- total removal Of load.
That the mining industry IS becoming
A..