These motors may constructed many
other ways; but for purposes this case is
only necessary consider the specific form
35 -which have thus generally described, my
improvements relate mainly such form.
NIKOLA TESLA, NEW YORK, Y.to working .
Application filed May20,1889.
The object present invention to
render this form motor more efficient and
to improve its action inode operation. To
obtain difference phase lag that is
suited . which energize one set the field-cores are
45 induced the motor itself, and the employ
ment external induction device thus
avoided. Let assumed that an
ordinaryalternating-eurrent generator con
nected circuit practically self-
induction, such, for example, asa circuit con
taining incandescent lamps only.United States Patent Office. The operation these motorsrhow
ever, dependent upon the existence a
certain difference phase between the cur-
50 rents theprimary and secondary coils. two the opposite
poles the field wind primary coils, which
arc connected the main circuit. the op- 60
eration the machine alternating currents
will bedeveloped the circuit, and tho phaées
of these currents will theoretically coincide
with the phases the impressed electro-mo-,
tive force., ASSIGNOR THE TESLA ELECTRIC
COMPANY, SAME PLACE.which
I have described other applications, and
which constructed follows: build field-
15 core with, say, four poles, between which is
mounted armature that generally wound
with closed coils. (Fomodel.27,1891.
The following explanations will serve to
illustrate the principle upon which said in- 55
vention based.
ELECTRO-MAGNETIC MOTOR.)
To all ;
whom may concern:
Be known that Nikola Tesla, sub
ject the Emperor Austria-Hungary, from
Sniiljan, Lika, border country Austria-IIun-
S gary, residing New York, the county and
State New York, have invented certain new
and useful Improvements Electro-Magnetic
Motors, which the following specifica
tion, reference being had the drawings ae
ro eompanying and forming part the same. the
20 same cores also wind secondary coils, which
are closed through coils the other pair or
set poles. The current generated the 95
secondary coil will react upon the primary
current, modifying the retardation the
same, according the amount self-induc
tion and resistance the secondary circuit. Serial Ho, 311,417.
SPECIFICATION forming part Letters Patent No. Assume next
that path currents formed across any
two points the above circuit, consisting, 75
for example, the primary induction
device. The phases the currents passing
through the primary, owing the self-in
duction the same, will not coincide with
the phases the impressed electro-motive 80
force, but will lag behind the same, sucli lag
being directly proportional the self-induc
tion and inversety proportional the resist
ance the said coil. The, insertion this
coil will also cause lagging retardation 85
pf the. -445,207, dated January. Next consider the
conditions imposed the association in
ductive relation with the primary coil, a
secondary coil.
If the secondary circuit have but little self- 100
induction—as, for instance, when contains
incandescent lamps only—it will increase the
.conditions the specific
object present invention.”
It will understood, course, that in
practice there always more less self-in
duction the circuit, which modifies cor
responding extent these conditions; but for 70
convenience this may disregarded the
consideration the principle operation,
since the same laws apply. Such currents may regarded 65
and designated the unretarded currents.
40 the motors constructed accordance
with this principle bring two energizing-
circuits into inductive relation the motor
itself—that say, the secondary currents
. this motor when alternat
ing current caused passthrough the pri
mary coils energizes directly one set of
25 poles and induces currents the secondary
coils, which act energize the other poles;
:but the phases the current the second
ary coils may differ time from those the
primary current, and hence rotation shift-
30 ing the polos effected that imparts rota
tion the motor.currents traversing and delivered by
the generator behind the impressed electro
motive force, such lag being the mean re
sultant the lag the current through the
primary alone and that what have des- 90
iguated the unrotarded current the
entire working-circuit.
Among the various forms alternating-
' current motors invented one
