New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1893-06-18
MyTUTWNyNTNINIMAA
OF FUTURE SPEED.

CONVERTING POWER INTO ELECTRICITY.
motive power into electricity This Is done by driv-
Ing dynamos. Every car on the route Is equipped
with motor which changes this electricity back into
motive power. To refresh the readers memory
r.cording the workings Of these machines simple
diagram is here Introduced. In this a represents
bar OF soft iron which has been wound with insulated
copper wire &C d.. Now, if this be quickly moved
past the north pole ca Of strong stationary mag
net (B) very close to the latter. the soft iron be
comes momenarily magne,izcd itself. and current
of electricity is excited by induction in the coil sur
rolrdng IT. IT, Immediately afterward, be SINH
larv pissed in front Of the pole :. the phenomenon
will be repeated but with this difference: the end of
the core nearest to the permanent magnet was made
n south pole before. but Is now converted mo
north pole. And not only has the polarity Of the
temporary magnet been reversed but the direction Of
the induced in the coil has been changed
also. By grouping large number Of such soft iron
cores and coils upon cylindrical frame, so that
the rotation Of the latter brings them directly In
front Of and a collection Of fixed magnets. the
same thing takes place. All the temporarily eX-
cited cnrren,s can be merged into Of great in
tensi,y but intermittent; and not only
Intermittent, but alternating In direction
That is what dynamo does. motor
constructed on much the same principle reverSrs
this operation Referring again 10 the diagram
suppose a be fixed and b movable" II an
alternating current he sent through ID. the end
OF the core nearest 10 Is WOULD EIpuN 'hiH-c '''
polarity At first. let us say, It would attract n
ond If the latter were not directly in front Of A.
II would be drawn thlthcr by magnetic force Having
thus acquired motion, however. IL wonld tend To
swing beyond the point of closest proximity and. as
q repclling influence. would promptly succeed the
attractive il would be- driven further away
but in the same direction The change Of polarity
which did this would attract = but scarcely would
Weld 10 this persuasion before fresh alienation
OF the current would send II along after y. The
framework on which is fastened having been rotated
a little on its axis by this proceeding. another
magnet would be brought into the place Of IT'S pred
ecessor only to be served in like manner Sufficient
repetition of this process would cause complete
revolution Of the movable apparatus: and the power
thus developed could be transferred from It's axis to
other machinery In practice both dynamo and motor
differ In several details from the device here described
bu; the principle is the same a motor, II may
be remarked. adds from 200 TO 200 pounds 70
the weight OF
1t now becomes necessary to convey the electricity
from dynamo 10 motor For this purpos" it is Gus
tomary except where storage batteries used.
to have two metallic conductors; one TO take the
current ont and the other to bring it back And
then some method has Ia De devised for connect
ing each with these two conductors to put the
motor "in circuit: that j., 10 lead portion Of the
current into and ont 81 that mechanism.
The device employed on all the electric railways
OF the country, with few exceptions. Is known as The
overhead wire and trolley" over the centre Of
the track from one end Of the line the other and
about seventeen feet from the ground. is strung a
bare copper wire This IS either sustained 10y pro
jecting arms from poles beside the track in The
illustration given herewith else by IL wire stretched
from a pole near one curba,one over the street to