New-York tribune., 1903-03-06
ELECTRIC POWER IN SHOPS.

In "Casser's Magazine" for March Professor
| ]. J. Flather reviews the progress lately maue
| in the use of electric power In factories anu
machine shops. He refers, Of course, to the
| well known economy effected by the aoohuon
| of shafting and cites by way of illustration the
action of the Baldwin Locomotive works. III
order to get rid of waste in transmission n1teen
or twenty small steam engines, properly dis
tributed. were substituted for one big one
Eventually, however, it vas found better 10
| adopt electric power, generated at one central
plant but transmitted with lnappreciaple JOSS
| to the various motors which did the work
In order to secure the largest efficiency from
| this system the writer points out that the char
| acter of the service must be carefully studied
before deciding whether to apply one motor to
every machine or to operate a group of ma
chimes with a motor of sufficient size. The
latter policy is wiser when the machines to De
driven are small and work intermittently. only
as much power as is actually needed Is then
consumed. For very heavy machine tools IL
will usually be advantageous to employ sepa-
rate motors.
One Of the principal objections to the use OF
electricity for driving machinery has been the
difficulty encountered in regulating the speed
economically. Most motors are so constructed
that they will waste current unless run at Ger
tain rather high rate. Consequently, while pre-
liminary adjustments are being made and low
speeds are necessary, an amount OF electricity
is often consumed which is all out or proper
| ton to the work. This has been especially true
with printing presses It is gratifying to know,
| therefore, that something like half dozen
| methods of varying the speed without serious
| loss Of energy are now known, some being ap-
| plicable to the direct current motor (which at
present is most extensively used and others
| being suited to one of the principal types OF
alternating current motor. Although Profes-
| sor FIather appears to be conversant with re-
cent advances in this branch Of the art, it may
| be added that still another method Of regulat-
| ing speed economically was recently described
| in "Engineering" According to that periodi-
cal, the system described, which had just been
applied to printing presses in London, involved
loss of only 2 per cent Of current at low
speeds. So many excellent ways OF overcoming
the evil having been found, a fresh access Of
popularity should be enjoyed by electric driving
in the Immediate future.
portion Of Professor Fathers article is de-
voted to use of compressed air for operating a
number of machines with power from one
source. In the convenience with which that
object can be attained this agent has been q
close rival of electricity. For some Of the work
now done by it compressed air will probably
| never be displaced. Nevertheless, Professor
Flather thinks that in instances enthusiasm
has outstripped good judgment. Several Of
| the tasks to which compressed air has been
applied could be performed equally we'll by
| hand, and perhaps cheaper. For still other
| purposes, in his opinion, electricity would be
more economical The mere fact that a ma
chine can be driven with compressed air does
| not prove that the latter is the best agent
Part of the waste which results is attributable
to failure to use the air properly-that is, to
heat it before expansion; but part of the trouble
Professor Flather believes, is inherent in one
| of the types Of motor with which 1t is made to
perform its work. Manufacturers who contem-
plate purchasing new power equipment will
find the article in "Casser's'' highly instructive