(No Model.
)
N TESLA.
METHOD OF ELECTRICAL POWER TRANSMISSION,
: No. 405,859, Patented June 25, 1889,
UNITED STATES PATENT OFFICE.
NIKOLA TESLA, OF NEW YORK, N. Y., ASSIGNOR TO THE TESLA ELECTRIC
COMPANY, OF SAME PLACE.
METHOD OF ELECTRICAL PoweR TRANSMISSION.
SPECIFICATION forming part of Letters Patent No. 405,859, dated June 25, 1889.
Application filed March 14, 1889, Serial No. 303,25l. (No model.)
To all whom it may concern: - In carrying out my present invention Icon
Be it known that I, NIKOLATESLA, a sub struct a generator with two coils or sets of
ject of the Emperor of Austria, from Smiljan, coils and a motor with corresponding energiz
Lika, border country of Austria-Hungary, re ing coils or sets of coils. By means of two
5 siding at New York, in the county and State line-wires one terminal of each generator-coil
of New York, have invented certain new and or set of coils is connected to one terminal of
useful Improvements in Methods of Electrical its corresponding motor-coil or set of coils,
Power Transmission, of which the following while the opposite terminals of the generator
is a specification, reference being had to the coils are joined together and likewise those of
to drawing accompanying and forming a part the motor.
of the same. To start the motor I establish temporarily
This application is for a specific method of an electrical connection between the points of
transmitting power electrically, shown and connection between the coils in the generator
described in, and covered broadly by the and those in the motor, so that the system
claims of, an application filed by me February becomes an ordinary double-circuit system
18, 1889, No. 300,220. identical with that described in my patent,
As is Well known, certain forms of alternat No. 390,413, of October 2, 1888, except that the
ing-current machines have the property, when generator and motor are constructed in any
connected in circuit with an alternating-cur Well-known way with a strong tendency to
20 rent generator, of running as a motor in syn synchronize. When by this plan of connec
chronism therewith; but, while the alternating tion the motor has attained the desired speed,
current will run the motor after it has at the earth-connection is severed, by which
tained a rate of speed synchronous with that means the system becomes an ordinary single
circuit synchronizing system.
of the generator, it will not start it; hence, in 75
25 all instances heretofore where these “syn In the drawing I have illustrated this
chronizing motors,” as they are termed, have method by a diagram.
Let G represent an ordinary alternating-cur
been run, some means have been employed to rent generator having four field-poles A, per
bring the motors up to synchronism with the
generator, or approximately so, before the manently or artificially magnetized, and an
3o alternating current of the generator is applied armature Wound With two coils C connected
to drive them. In some instances mechanical together in series. -
appliances have been utilized for this pur Let M represent an alternating-current mo
pose. In otherS Special and complicated tor With, Say, four poles D, the coils on which
forms of motor have been constructed. are connected in pairs and the pairs connected
35 My present invention is an improvement in in Series. The motor-armature should have
methods of operating these motors and in polar projections and closed coils E.
volves a new and improved plan of bringing From the common joint or union between
the motor up to the proper rate of speed, that the two coils or sets of coils of both the gen
it may be run in synchronism with the gen erator and motor an earth-connection F is es
4o erator. tablished, While the terminals or ends of the
The expression “synchronism with the gen said coils or circuits which they form are con
erator’ is used herein in its ordinary accepta nected to the line-conductors III.
tion-that is to say, a motor is said to syn Assuming that the motor is a synchronizing
chronize with the generator when it preserves motor, or one that has the capability of run 95
45 a certain relative speed determined by its ning in synchronism with the generator, but
number of poles and the number of alterna not of starting, it may be started by the above
tions produced per revolution of the gener described plan by closing the ground-connec
atOr. Its actual speed, therefore, may be . tion from both generator and motor. The
faster or slower than that of the generator, System thus becomes one with a two-circuit IOO I
but it is said to be synchronous so long as it generator and motor, the ground forming a
preserves the same relative speed. COmmon return for the currents in the two
2
405,859
wires II II. When by this arrangement of motors herein described, which consists in
circuits the motor is brought to speed, the electrically connecting intermediate points of
ground-connection is broken between the gen the inducing-circuit of the generator and the
erator or motor or both and ground, switches energizing-circuit of the motor until the motor
IX IX being employed for this purpose. The has reached a desired speed and then inter
motor then runs as a synchronizing motor. rupting such connection, as Set forth.
This system is capable of various useful ap 2. The method herein described of starting
plications which it is not necessary to describe or operating synchronizing motors, which con
in detail; but it will be enough to say that the sists in electrically connecting intermediate
O
convertibility of the system from double cir points of the inducing-circuit of the generator
cuit to single circuit is a feature in itself of and the energizing-circuit of the motor to
great value and utility. aarth until the motol has reached the desired
I do not wish to be understood as confining speed and then interrupting either or both of
myself to the precise arrangement or order of the ground-connections, as set forth.
connections herein set forth, as these may be NFIKOLA TESLA.
obviously varied in many respects. Witnesses:
What I claim is-- EDWARD T. EVANs,
1. The method of operating synchronizing E. C. UPSTILL.
