(No Model.) 3 Sheets-Sheet 1.

N TESLA,
DYNAMO ELECTRIC MACHINE,
No. 359,748, Patented Mar, 22, 1887.

.2%-4.2
27
E. (A ----.
-------.
-

t;
: -----------
2W
2 ---
% --- r
NM. V.N 7NN
i.vx
arS. w
Na SWXW.
NW2 ; :
ar
at se
N
Ay Sc
N
(No Model.), 3 Sheets Sheet 2.
N. TESLA,
DYNAMO ELECTRIC MACHINE,
No. 359,748, Patented Mar, 22, 1887.

IZ I

-»
-

*yº
·?
No.?
.
|
:·
ºù
2 ,2%
 UNITED STATES PATENT OFFICE.
NIKOLATESLA, OF, SMILJAN LIKA, AUSTRIA-HUNGARY, ASSIGNOR TO THE
: TESLAELECTRIC LIGHT AND MANUFACTURING COMPANY, OF RAHWAY,
NEW TERSEY.

DYNAMO-ELECTRIC MACHINE.
SPECIFICATION forming part of fetters Paterat No. 359,748, dated March 22, 1887.
Application fied January 14, SSG. Renewed December 1, 1886, Serial No. 220,370. (No model.)

To ?till vil. On it 7 lay conce77. nets currents are generated in the iron body 5o
Beit known that I, NIKOLATESLA, of Smil of the armature which develop heat, and con
jan Lika, border country of Austria-Hungary, sequently cause a waste of power. Owing to
have in veluted certain Improvements in Dy the mutual action of the lines of force, the mag
namo-Electric Machines, of which the follow. netic properties of iron, and the speed of the
ing is a specification. different portions of the armature-core, these 55
The main objects of my invention are to in currents are generated principally on and near
crease the efficiency of the machine and to fa the surface of the armature-core, diminishing
cilitate and cheapen the construction of the in strength gradually toward the center of the
IO same; and to this end my invention relates to core. Their quantity is under same conditions
the magnetic frame and the armature, and to proportional to the length of the iron body in 6o
other features of construction, hereinafter more the direction in which these currents are gen
fully explained. erated. By subdividing the iron core electric
My invention is illustrated in the accompa ally in this direction the generation of these
inying drawings, in Which Figure is a longi currents can be reduced to a great extent. For
tudinal section, and Fig.2 across-section, of the instance, if the length of the armature-core is 65
machine. Fig. 3 is a top view, and Fig. 4 a side twelve inches, and by a suitable construction
view, of the magnetic frame. Fig. 5 is an end the same is subdivided electrically, so that there
view of the commutator-bars, and Fig. 6 is a are in the generating direction six inches ofiron
section of the shaft and commutator - bars. and six inches of intervening air-spaces or in
Fig. 7 is a diagram illustrating the coils of the sulating material, the currents will be reduced to
armature and the connections to the commu to fifty per cent.
tator-plates. As shown in the drawings, the armature is
The cores e g c 0 of the field-magnets may be constructed of thin iron disks D DD, of vari
25 tapering in both directions, as shown, for the ous diameters, fastened upon the armature
purposes of concentrating the magnetism upon shaft in a suitable manner and arranged ac. 75
the middle of the pole-pieces. cording to their sizes, so that a series of iron
The connecting-frame F F of the field-mag bodies, iii, is formed, each of which dinnin
nets is in the form indicated in the side view, ishes in thickness from the center toward the
Fig. 4, the lower part being provided with the periphery. At both ends of the armature the
spreading curved cast legs e e, so that the ma inwardly-curved disks did, preferably of cast 8o
chine will rest firmly upon two base-bars, ' '. iron, are fastened to the armature-shaft.
To the lower pole, S, of the field-magnet M. The armature - core being constructed as
is fastened, preferably by means of Babbitt or shown, it will be easily seen that on those por
other fusible diamagnetic material, the base tions of the armature that are the most remote
B, which is provided with bearings b for the from the axis, and where the currents are 85
armature-shaft H. The base B has a projec principally developed, the length of iron in
tion, P, which supports the brush-holders and the generating direction is only a small frac
the regulating devices, which may be of any tion of the total length of the armature-core,
ordinary character, or may be such as shown and besides this the iron body is subdivided
in an application of like date here With. in the generating direction, and therefore the 9o
The armature is constructed with the view Foucault currents are greatly reduced. An
to reduce to a minimum the loss of power due other cause of heating is the shifting of the
to the transversal or Foucault currents and to poles of the armature-core. In consequence
the change of polarity, and also to shorten as of the Subdivision of the iron in the armature
much as possible the length of the inactive and the increased surface for radiation the 95
wire wound upon the armature-core. risk of heating is lessened.
It is well known that when the almature is The iron disks DDD may be insulated or
revolved between the poles of the field-mag coated with some insulating-paint, a very care.
 359,748

ful insulation being unnecessary, as an elec In constructing the armature-core and wind
trical contact between several disks can only ing and connecting the coils in the manner in
occur on places where the generated currents dicated, the passive or electrically-inactive
are comparatively weak. An armature-core wire is reduced to a minimum, and the coils
constructed in the manner described may be at each side of the plates that are in contact
revolved between the poles of the field-mag with the brushes are practically equal, and in
nets without showing the slightest increase of this way the electrical efficiency of the ma
temperature. chine is increased.
The end disks, dd, which are of sufficient The commutator-platest are shown as out
thickness and, for the sake of cheapness, pref.
O side the bearing b of the armature-shaft. The
erably of cast-iron, are curved in Wardly, as shaft. His tubular and Split at the end portion,
indicated in the drawings, The extent of the and the wires are carried through the same in
curve is dependent on the amount of wire to any usual manner and connected to the re
be wound upon the armatures. In my present spective commutator-plates. The commuta
invention the wire is wound upon the arma tor-plates are upon a cylinder, t, and insul
ture in two superimposed parts, and the curve lated, and this cylinder is to be properly placed
of the end disks, dd, is so calculated that the and secured by expanding the split end of the
first part-that is, practically half of the wire shaft by a tapering screw-plug, c.
just fills up the hollow space to the line aca; I do not clain herein the cores of the field.
or, if the wire is wound in any other manner, magnets converging toward the pole-pieces;
the curve is such that when the whole of the nor do I claim the method of fastening the
wire is wound the outside mass of wires,w, and base to the lower field-magnet, as this has been
the inside mass of Wires, c', are equal at each claimed in my former application on dynamo
side of the plane aca. In this case it will be electric machines.
25 seen the passive or electically-inactive wires What I clain is
are of the smallest length practicable. The 1. In a dynamo. (electric machine, the arma
arrangement has further the advantage that ture constructed of iron disks of various di
the total lengths of the crossing wires at the ameters arranged upon the shaft in such a
two
equal.
sides of the plane ac a' are practically manner that a series of iron bodies is formed,
each diminishing in thickness from the cen
To further equalize the armature-coils at ter to the periphery, substantially as and for
both sides of the plates that are in contact the purposes set forth.
with the brushes, the Winding and connecting 2. In a dynamo-electric machine, the alma
up is effected in the following manner: The ture-core having iron disks of various diame
whole wire is wound upon the armature-core ters, in combination with in Wardly - curved
in two superimposed parts, which are thor end disks, for the purposes and substantially
oughly insulated from each other. Each of as Set forth.
these two parts is composed of three separated 3. In a dynamo-electric machine, an arma
groups of coils. The first group of coils of the ture-core having inwardly - curved ends, in
first part of wire being wound and connected combination with the ar mature-coils, the cross
to the commutator-bar's in the usual manner, ing wires of which coils pass into the concave
this group is insulated and the second group heads and project equally, substantially as set
wound; but the coils of this second group in forth.
stead of being connected to the next following 4. In a dynalmo-electric machine, an arma
5 commutator-bars, are connected to the directly. ture having separate coils superimposed and
opposite bars of the commutator. The second connected to the commutator. plates in alter
group is then insulated and the third group nating groups, Substantially as set forth.
Wound, the coils of this group being connected 5. An armature for dynamo - electric ma
to those bars to which they would be con chines, having a core composed of disks of va
nected in the usual Way. The wires are then rious diameters, in combination with separate
thoroughly insulated and the second part of Superimposed coils connected to the commu
Wire Wound and connected in the same man tator-plates in alternate groups, Substantially
her. Suppose, for instance, that there are as set forth.
twenty-four coils-that is, twelvein each part 6. In a dynamo. electric machine, the mag
55 and consequently twenty-four commutator netic frame composed of the cores c. c. cc, the
plates. There will be in each partthree groups, curved pole-pieces NS, and the connecting
each containing four coils, and the coils will frame with the curved and outwardly - pro
be connected as follows: jecting legs e e, substantially as described.
Groups. Committatto)'-ba's. Signed by me this 12th clay of January, A.
First....... ........ I - 5 D. SS6.
First part of wire & Second............ 17-21
Third ... ... 9-13 NIKOLATESLA.
First.. ..13-17 Witnesses:
Second part of Wire - Second............ 5- 9 GEO. T. PINCKNEY,
65 Third.............21- 1 WALLACE I, SERRELL.