The Wichita daily eagle. [volume] (Wichita, Kan.) 1890-1906, 1903-04-25
SMALL ELECTRIC MOTORS.

L
4 In the current number of Engineering.
Frederick N. kinball gives a brief
| sketch of the history of electric motors.
tracing their development from the first
type TO the standard motor Of the pres
ent day He shows a tremendous adj
vance in the last ten years and declares
that there is no piece of apparatus OF the
size and weight sold for the price which
embodieS the results of more painstaking
work on the part of designing engineers
and the expenditure OF more money on
experimental work than the small motor
| OF the present day. He says further
that when one considers the enormous
amount OF power generated and diStri5-
uted for manufacturing purposes in the
United States, and then remembers that
| probably less than : per cent OF all this
| power is distributed electrically some
idea may be formed of the possibilities
yet urrealized by the use of electric mo-
| tors 1t is estimated that there are at
| the present time not less than e. COZ
| motors in use, exclusive of those used
for railways. automobiles fans and ele-
| vators, supplying something like 1.oop.00o
| horsepower. and representing an invest
| ment of 100000.
The advantages of the electric motor
/ for machine driving are pointed out, and
it is said that there is no problem Of
| more vital interest 10 the small manufac-
| turer than that of obtaining a reliable.
| simple. and continuous source of power
This question frequently causes the loca-
! ton of factories in out-of-the-way. badly
ventilated, and badly lighted shops This
| could be avoided by adopting a motor
| drive. The electric drive is, further
more. economical because the user pays
| for only the power consumed. Another
advantage is that by introducing indicat
/ ing instruments the superintendent can
I franffpDrlV a n ffS1 of TsOV or
and thus locate a badly working ma
/ chine. This is a valuable feature of cleo
| trio driving, as it often discovers the
abuse of lathes and other machines by
| the piece workers having care of them.
The final results Of all these desirable
features of the use of motors are in
creased output. lower cost, higher quality
of product. and larger profits.
A novel form of electric furnace for the
reduction of ores and metals has re-
Gently been patented. and should prove in
tereSting, as il involves new and radical
departure This furnace depends upon
the principle of electrical iacandescence in
the same manner as the ordinary mean
descent lamp. Electric furnaces prior TO
this time have consisted Of two general
types: the arc furnace, and a form of
incandescent furnace consisting of wires
encaSed in comparatively infusahle
enamel. The inventor was led to conclude
from long experience in the manufac-
ture Of iron and steel that the arc fur
mace produces a heat too intense and
concentrated to be used to advantage in
the reduction of iron and other ores. and
that more diffused and less intense
heat would be desirable and he con-
sequently devised an incandescent furnace
the operation of which depends upon
the heat produced by the passage of an
electric current through a medium con-
sisting of a mixture of infgsable sub
stances. such as graphite and fire clay
the conductivity of the mixture obviously
depending upon the conductivity of the
various ingredients. IT. is claimed that
almost any degree of heat, from boiling
water to molten iron can be produced
with substantially the same piece of APP
paratus merely by varying the amount of
current flowing through it, and that the
intensity of the heat can be maintained or
varied with equal facility.
new form Of insulating material to
take the place of the gradually decreasing
supply of gutta-percha is thus described
in the Scientific American: THE com
pound has been especially prepared TO
meet the requirements of electric railway
light and power insulation. II is very
hard, dense, tough, and strong of a
brownish hue. resembling somewhat that
of certain varieties of oak The com
pound is cast in the various forms which
are required, so that the drilling ana |
working necessary tor some OF the mate |
rails formerly used for electrical work /
are no longer necessary. Elaborate tests /
which have been carried out by the en- /
gfneer of the Niagara Falls Power com I
pany and by Prof. Sheldon of the Brook |
Ign Polytechnic Institute give some idea /
of the resistant qualities of this new
material. The Niagara Falls engineer |
found that cap with an embedded bolt |
arcked across at~S0.0 900 volts; round top. /
straight line hanger arcked across at /
1l.O00 volts; a square foot of tie ma (
terial one-quarter of inch n thick |
ness arcked around at 70 sp -soits: an s.
inch round column arcked around at 1o0
900 volts; as did also an S-inch heXagonal |
None of these specimens was
punctured. with the exception of a ball
insulator. which was punctured at 14000
volts the puncture being probably due
to some mechanical defect
In order TO show that the round-top
hangers of electrose fully meet the re
quirements of trolley line construction.
Professor Sheldon carried out the follow
ing test: 4 round-top hanger was sus-
pended. free from draft IN an inverted
position by means of a bronze ear weigh
ing eight ounces. and measuring i've and
a half inches in length. the ear clamping
the metal on a round rod of soft iron
of an inch IN diameter and
twenty inches long. From the hanger
top was suspended a weight of 9Jo pounds :
A current Of 200 ampeTes was passed con-
tinuously through the rod for one hour.
The rod was thereby maintained at a red
heat This supply Of heat. which is prac-
tically the same as would be given by
red-hot trolley wire Of the same size IN
the same time. did not affect the cleo
trose insulation To such an extent as 10
allow the 20 pounds weight To tear asun-
Ter the metal parts OF the hangers. Pro
lessor Sheldon tested a feeder iusulator
under a voltage Of 1000. bat the insUla-
ion did NOT break down. Similar re-
suits were obtained with cap and cone
hangers. feeder iusulators. globe strain
nsulators. solid bolts. terminal strain in
ulators, and sheets. The resistance q the
substance 10 atmospheric Influences and
general wear renders il Of great service
'or outside work. The substance IS
moulded into many forms and can De
Ised as a general substitute for rubber
Tot only IN electrical work. but In photo
IRA phic and other work as wei.