precise rules can be
given for the specific construction and pro- 90
portions for securing the best results, this
is matter determined experiment and
calculation particular cases; but the gen
eral plan construction which have de
scribed will foundunder all conditions 95
conduce the attainment this result. 345,390. Fig., ASSIGNOR THE TESLA ELECTRIC
COMPANY, SAME PLACE. more perfectly 55
attain this condition obtain secure an
increased retardation the secondary cur
rent the following manner: Instead ofbring
ing the primary and secondary coils cir
cuits transformer into the closest possi- 60
ble relations, has hitherto been done, pro
tect measure the secondary from the in
ductive action effect the primary sur
rounding either the primary the secondary
with comparatively-thin magnetic shield 65
screen.)
To whom concern:
Be known that sub
ject the Emperor Austria-IIungary, from
Smiljan, Lika, border country Austria-
5 Hungary, residing New York, the county
and State New York, have invented certain
new and useful Improvements Electrical
Transformers pi-induction Devices, which
the following specification, reference be-
ro ing'hadto the drawings accompanying and
forming part the same.nited States Patent Office.
NIKOLA TESLA, NEW YORK, Y.
In the accompanying drawings have illus
trated the construction above set forth. On
35 the other hand, the lag the primary behind
the impressed electro-motive force maybe di
minished loadingthe secondary with non-
inductive dead resistance—such incan
descent lamps—wherebythe time intervalbe-
40 tween the maximum the minimum periods
of the primary and secondary currents in
creased.
ELECTRICAL TRANSFORMER INDUCTION DEVICE. Serial Bo.
In transformers constructed now- and
heretofore will found that the electro
motive force the secondary very nearly co
incides with that the primary, being, how-
25 ever, opposite sign. (Bomodel. This time interval, however, lim
ited, and the results obtained phase dif
ference the operation such devices as
45 alternating-current motors can only be
approximately realized such means pro
ducing securing this difference, above
indicated, for desirable such casesthat
there should exist between the primary and
50 secondary currents, those which, however
produced, pass through the two circuits the
motor, difference phase ninety de
grees; or, other words, the current one
circuit should maximum when that the
other circuit minimum.
This invention improvement elec
trical transformers converters, and has for
its main objects the provision means for se-
15 curing, first, phase difference between the
primary and secondary currents adapted to
the operation alternating-current mo
tors and other like purposes, and, second, a
constant current for all loads imposed upon
20 the secondary.1890. have further discovered that such
a transformer may, properly proportion
ing its several elements and determining in
a manner well understood the proper relations 85
between the primary and secondary windings,
the thickness the magnetic shield, and other
conditions, constructed yield constant
current all loads. simi- 100
. 433,702, dated August 5,1890.
Figure cross-section transformer
embodying improvement. Under these conditions circum
stances, long the primary current has a
small value, the shield protects the secondary;
but soon the pritnary currenthas reached
a certain strength, which arbitrarily deter- 70
mined, tlieprotectingmagneticshieldbecomes
saturated and the inductive action upon the
secondarybegins. the same time the
currents, both primary and secondary, lag be
hind their respective electro-motive forces;
but this lag practically nearly the
same the case each follows that the
30 maximum and minimum the primary and
secondary currents will nearly coincide, but
differ sign direction, provided the sec
ondary not loaded contain devices
having the property self-induction. Itresults,therefore,tliatthe
secondary current begins flow certain
fraction period later than would without 75
the interposed shield, and since this retarda
tion may obtained without necessarily, re
tarding the primary current also, addi
tional lag secured, and the time interval be
tween the maximum minimum periods 80
the primary and secondary currents in
creased.
SPECIFICATION-forming part Letters Patent No.
Apulicationfiled March 26
