Its actual speed, therefore, may faster
or slower than that the generator; but 55
said synchronous long preserves
the same relative speed.
SerialN
o. Hence, all
20 instances heretofore where these “synchro
nizing-motors,” tliey are termed, have been
run some means have been adopted bring
the motors synchronism with the gen
erator, approximately so, before the alter-
25 nating current the generator applied to
drive them.
The expression “synchronous with that of
the generator,” used herein its ordinary
acceptation—that say, motor said to
50 synchronize with the generator when pre
serves certain relative speed determined by
its number poles and the number alter-
Patent No. other words, cer
tain change the circuit-connections the
35 motor convert will from double-cir
cuit motor, such have described in
prior patents and applications, and which will
start under the action alternating cur
rent into synchronizing-motor, one which
40 will run the generator only when has
reached certain speed rotation synchro
nous with that the generator. (N
o m
odel,1
nations produced per revolution thegener-
ator. 300,220. and modifica
tions the same. When the 75
speed the motor lias thus been brought to
the desired rate, the switch shifted throw
the main current directly through the motor-
circuits, and although the currents both
circuits will now the same phase the So
motor will continue revolve, becoming a
true synchronous motor.
There are various modifications and impor- 85
tant features this method plan;but the
main principle the invention will under
stood from the foregoing.
SPECIFICATION forming part Letters
A
pplicationfiledFebruary18,1889,
To all whom, concern:
Be known that Nikola Tesla, sub
ject the Emperor Austria, from Smiljan,
Lika,border country Austria-Hungary, and
5 residing NewYork, the county and State
of New York, have invented certain new and
useful Improvements Methods Operating
Electro-Magnetic Motors, which the follow
ing specification, reference being had to
i the drawings accompanying and forming a
part the same. some instances mechanical
appliances have been utilized for this pur
pose.
METHOD OPERATING ELECTRO-MAGNETIC MOTORS.
As well known, certain forms alternat
ing-current machines have the property, when
connected circuit with alternating-cur-
15 rent generator, running motor syn
chronism therewith; but,while the alternating
current will run the motor after has attained
a rate speed synchronous with that the
generator, will not start it. 95
Referring Fig. Tiie field-magnets are wound with two
sets coils, the terminals which arc con
nected switch mechanism, means 65
which the line-current may carried directly
through the said coils indirectly through
paths which its phases are modified. this
manner enabled very greatly extend
the applications system and secure
45 all the advantages both forms alternat
ing-current motor. The construe- 60
tion which prefer for this that which
the armature provided with polar projec
tions.
In the drawings, which now refer, I
have illustrated the diagrams the general 90
features construction and operation which
distinguish invention, Figure being-
drawn illustrate ■
the details the plan
above set forth, and Figs. others special and complicatedforms
of motor have been constructed. secure greater
efficiency, wind the armature its polar pro
jections with coils closed themselves. 1,let designate the field-
magnets motor, the polar projections of
which are wound with coils included in
independent circuits, and the armature
with polar projections wound with coils 100
closed upon themselves, the motor these
respects being- similar construction those
described patent, No.
In carrying out invention construct a
motor which has strong tendency synch
ronism with the generator.United States Patent Office. To
start such motor, the switch turned onto
a set contacts which includes one motor- 70
circuit dead resistance, the other in
ductive resistance, and, the two circuits being-
in derivation, obvious that the difference
in phase the current such circuits will
set rotation the motor.
NIKOLA TESLA, NEW YORK, Y. 401,520, dated April 16, 1889. have dis-
30 covered much more simple method plan
of operating synchronizing-motors, which re
quires practically other apparatus than
the motor itself. 382,279, dated
May 1888, but having-, reason the
