The arma
ture has two coils and The-former is
closed upon itself, the latter connected with
• the field and line through contact-rings b,
brushes cl, and switch the start
60 the coil alone active and the motor tends
to run speed above the synchronous; but
when the coil connected the circuit
the number armature-poles increased,
while the motor made true synchronous
65 motor. the start short-circuit one only,
thereby producing number poles the
. Gaylord,
Frank Hartley. The method operating alternating-
current motors having field-coils different
self-induction, which consists directing al
ternating currents from external source
through the field-circuits and short-circuiting
a part the armature-circuits, and then when
the motor has attained given speed direct
ing the alternating currents through both the
field and one more the armature-circuits,
as set forth.
This may accomplished various ways;
but for all practical purposes the following
will suffice: wind the armature two sets
45 coils.
0.
I not claim herein the method and
means described and shown for operating. starting the motor the
shunt closed around both coils. such a
disposition shown. The two armature coils
are series with the field-coils and the same
15 disposition the shunt short circuit is
used. Itis ofadvantage the operation mo
tors this kind construct wind the arma
ture such manner that when short-circuited
on the start will have tendency reach a
20 higher speed than that which synchronizes
with the generator. The method operating alternating-
current motors having field-coils different
self-induction, which consists directing al
ternating currents from external source
through the field-circuits only until the mo
tor has reached given speed and then di
recting said currents through both the field-
circuits and one more the armature-cir
cuits, set forth. This is
shown Fig. increase the tendency synch
ronism, two circuits may used the arma
ture, one which short-circuited the
start and both connected with the external
circuit after the synchronous speed reached
or passed. When such
limit reached passed, the current di-
50 rected through the other coil, which, in-,
creasing the number armature-poles, tends
to maintain synchronism. This disposition has the advantage
that the closed armature-circuit imparts to
the motor torque when the speed falls off, but
at the same time the conditions are such that
the motor comes out synchronism more
readily. The ar
mature-winding maybe similar that the
field—that say, the armature may have
two more coils wound adapted for dif-
5 ferent self-induction and adapted, prefera
bly, produce the same difference phase
as the field-coils. This disposition shown Fig. For example, given mo
tor having, say, eight poles should run, with
the armature-coil short-circuited, two thou
sand revolutions per minute bring to
25 synchronism.
Witnesses:
R obt.
3.416,193
coils, multiple arc therewith.
What claim is—:
1. Fig. This short-circuits one
of the armature-coils, The other coil
F out circuit and open. The motor having,
say, eight poles contains two field-circuits A
55 and different self-induction. On
starting, the switch turned complete
the connection between one binding-post P
and the field-coils.
70
1
75
80
85
90
95
I O
io 5
no
” 5
120
I2. There are three contact-rings and
three brushes which connect the arma
ture-circuits with the external circuit.
Both armature-coils are thus active. The method herein described operat
ing alternating-current motors having inde
pendent energizing-circuits, which consists
in short-circuiting the armature circuit or
circuits until the motor has reached passed
a synchronizing speed and then connecting
said armature-circuits with the external cir
cuit, set forth. will generally happen, how
ever, that this speed not reached, owing to
the fact that the armature and field currents
do not properly correspond, that when the
current passed through the armature (the
30 motor not being quite synchronism)
there liability that would not hold
on,” termed. When the
motor speed, the switch turned
back, that the connection from binding-
post the field-coils through the coil
G, and switch closed, thereby including
coil multiple arc with the field-coils.
NIKOLA TESLA. which the armature-coils
io are indicate their different elec
trical character, have shown circuit with
them, respectively, the resistance and the
self-induction coil S'. therefore prefer so
wind construct the motor that the start,
when the armature-coils are short-circuited,
3 the motor will tend reach speed higher
than the synchronous—as,for instance, double
the latter. . armature, which will tend run the speed up
above the synchronous limit.
From the above-described instances is
evident that many other dispositions for car
rying out the invention are possible. such case the difficulty above
alluded not felt, for the motor will al
ways hold synchronism the synch-
40 ronous speed—in the case supposed two
thousand revolutions—is reached passed.a
motor producing artificially difference
of current phase its independent ener
gizing-circuits; nor claim, broadly, a
motor having independent energizing-cir
cuits different self-induction and arma
ture-circuits connected therewith, these
features are made subjects other applica
tions which have filed.
2
