The Electric Motor in Mining Operations. [Volume: 8, Issue: 1, 1888, pp. 29-36]

30

UNITED STATES ASSOCIATION OF

[VOL. 8,

some 7,000,000 h. p., to Boston But, would it pay? is the question to solve. Taking all the electric-lights throughout the
country, and roughly figuring, we find that there is fully 250,000
h. p. engaged in producing electricity every night in the year. *
* * I think it safe to say,.that for every h. p. used in mining there are ten employed in producing electricity. * * *
An arc-light consumes about.8 of a horse-power of electric
energy; now there are almost innumerable circuits from 10 to 50
miles long throughout our country with arc-lights indiscriminately
placed their entire length. This is practically transmitting power;
for a motor could be placed where an one of the lights is.
Abroad, Marcel Deprez has transmitted 40 I. p. through 70 miles
of wire, with a commercial efficiency of 56 per cent. Mr. Brown,
in Switzerland, has put into practical operation a plant transmitting 50 h. p. 5 miles, with a commercial efficiency of over 70 per
cent. The Thomson-Houston dynamos are over 90 per cent. efficiency, as are also their motors. Therefore, if a steam-engine
dynamo and motor were placed side by side we would obtain, of
the 100 indicated h. p. of the engine, over 81 h. p. in mechanical
power from the motor.
To whatever distance we remove the motor from the dynamo
we lose power in the circuit. Copper is the best conductor of
electricity, and yet this offers resistance.- To decrease this resistance, we have to increase the conductors in size. This point is
similar to the general practical rules governing hydraulic transmission. * * *
Motors have been used successfully for drilling by impact and
boring with diamond drills. The latter method was successfully
used several years ago by M. Taverdon, in France, and in his experiments he was fully able to compete with steam or compressed
air. In rapid tunneling, in running adit-levels, in deep and
crooked workings, or in all work requiring hasty construction, the
great trouble and expense of shifting and relaying pipes, with
great losses due to leakage, etc., is avoided. The necessary wires
are simply cleated to wall or posts as work advances, thus always
being entirely out of the way. In surface-work, the area over
which we can work before changing steam-plant is vastly increased.
In any direction, over rocks, hills or gullies, on a straight line run
the wires, for miles if desired, and drilling and boring can still go