METHOD OPERATING ELECTRO-MAGNETIC MOTORS. 80
the armature-circuit, the terminals which
are rings Brushes bear these
rings and connect with the line and field
circuits. For . the shunt short circuit
around the armature. the switch there- 85
in. SerialH
o, 311,414, (Ho model,)
To all whom concern:
Be known that Nikola Tesla, sub
ject the Emperor Austria, from Smiljan,
Lika, border country Austria-Hungary, and
5 resident New York, the county and
State New York, have invented certain
new and useful Improvements Methods of
Operating Electro-Magnetic Motors, which
the following specification, reference be-
io ing had the drawings accompanying and
forming part the same.
NIKOLA TESLA, NEW YORK, Y.
In the drawings hereto annexed have
illustrated several modifications the plan 70
above set forth for operating motors. Under these condi
tions the motor has strong tendency to
synchronism.
SPECIFICATION forming part Letters Patent No. The arma-
45 ture wind with one more coils, which are
connected v’ith the field-coils through contact
rings and brushes, and around the armature-
coils arrange shunt with means for open
ing closing the same. This have heretofore done
by change the circuit-connections, where
by the start the poles resultant attrae-
20 tion the field-magnets the motor were
shifted rotated the action the current
until the motor reached synchronous speed,
after which the poles were merely alternated. When the current directed throiigh
the motor, divides between the two circuits,
(it not necessary consider any case where
there are more than two circuits used,) which, 55
by reason their different self-induction,
secure difference phase between the two
currents the two branches that produces
a shifting rotation the poles. When the desired speed reached,
the shuntaround the armature-coils opened
and the current directed through both anna- 65
ture and field coils.
Application filedM
ay20, 1889. the present case the armature- 105
coil, instead being series with the field-
., ASSIGNOR THE TESLA ELECTRIC
COMPANY, SAME PLACE.have shown and described a
method starting and operating synchro-
15 nizing motors whichinvolved the transforma
tion the motor from torque synchro
nizing motor.
Fig This diagram differs from the pre
vious one only respect the order con
nections.
The present application based upon another
25 way accomplishing this result, the main
features being follows: alternating
current passed through the field-coils only
of motor having two energizing-circuits of
different self-induction arid the annature-
30 coils short-circuited, the motor will have a
strong torque, but little tendency to
synchronism with the generator; but the
same current which energizes the field be
passed also through the armature-coils the
35 tendency remain synchronism very
considerably increased.
Figure and designate the field-coils
of the motor. 416,192, daied December 3,1889. the
alternations current other currents are 60
induced the closed—or short-circuited—
armature-coils and the motor has strong
torque.
In patent granted April 16, 1889,
No.nited States Patent Office. The
figures are diagrams, and will explained
in their order. This due the
fact that the maximum magnetic effects pro
duced the field and armature more nearly
coincide. This principle discovered I
40 have utilized the operation motors.instance, the motor have eight
poles—four each circuit—there willbe four
resultant poles, and hence the armature-wind
ing should such produce four poles, 100
in order constitute true synchronizing
motor.
It will observed that such dispose
tion illustrated Fig. therefore important ob- 95
serve the proper rule winding the arma
ture. the field-cir
cuits and being different self-induc- 90
tion, there will always greater lag of
the current one than the other, and
that, generally, the armature phases will not
correspond with either, but with the result
ant both. starting this mo-
50 tor close the shunt around the armature-
coils, which will therefore closed cir
cuit. the circuits including these 75
coils are different self-induction, have
represented this resistance-coil cir
cuit with and self-induction coil cir
cuit with The same result may course
be secured the winding the coils. 401,520, . The operation these devices have '
stated above. In
other words, construct motor having in
dependent field-circuits different self-in
duction, winch are joined derivation a
source alternating currents
