The combinatiou, with the commutator- 85
bars and intervening insulating material and
brushes inadyuamo electric machine, ofasolid
insulator bad conductor electricity ar
ranged bear upon the surface the com
mutator adjacent the end the brush, for 9c
the purpose set forth. electric apparatus which sliding
contacts with intervening insulating material
are employed, the combination, with the con
tact springs brushes, solid insulator 95
bad conductor electricity, and for the
purposes set forth.
Witnesses:
Geo. 334,823, dated January 26,1886. It
will seen that whenever one commutator- 60
segment passes out contact with the brush
the formation the arc will prevented by
the intervening insulating material coming in
contact with the insulating material the
brush.
COMMUTATOR FOR DYNAMO-ELECTRIC MACHINES.
2.
NIKOLA TESLA, SMILJAN LIKA, AUSTKIA-HUNGAKY, ASSIGNOK THE
TESLA ELECTRIC LIGHT AND MANUFACTURING COMPANY, RAHWAY,
NEW JERSEY.nited States Patent Office.
The sparking may reduced various de
vices, such providing path for the cur-
30 rent the moment when the commutator
segment bar leaves the brush, short-cir
cuiting the field -helices, increasing the
number the commutator-bars, other
similar means; but all these devices are ex-
35 pensive not fully available, and seldom at
tain the object desired.)
To all whom, may concern:
Be known that Nikola. Pinckney,
W illiam Mott.
I claim invention—•
1.
45 invention will easily understood by
reference the accompanying drawings. (No model.
In Fig.
SPECIFICATION forming part Letters Patent No. 104,534.
Application filed May 6,1885.
My invention enables prevent the
sparking simple manner.
Signed this day May, D.
NIKOLA TESLA.
In Fig. the first case the
spark more apparent, there the mo
ment when the circuit btoken discharge
of the magnets through the field-helices, pro-
25 during great spark flash whicli causes an
unsteady current, rapid wear the commu
tator bars and brushes, and waste power. This spark may due the break of
the complete circuit, shunt low re-
20 sistance formed the brush between two or
more commutator-bars. similar view, represent-
50 ing two plates mica upon the back the
brush. Serial No. simple arrangement shown
with two plates mica other material. 80
My invention may applied any elec
tric apparatus wflvich sliding contacts are
employed.
My invention relates the commutators
on dynamo -electric machines, especially in
machines great electromotive force, adapted
io arc lights; and consists device by
means which the sparking the commu
tator prevented
It known that machines great elec
tromotive force—such, for instance, those
15 used for arc lights—whenever one commutator
bar plate comes out contact with the col
lecting-brush spark appears the commu
tator. 65
My invention may carried out many
ways; and not limit myself any particu
lar device, invention consists, broadly,
in providing solid non-conducting body to
bear upon the surface the commutator, 70
the intervention which body the sparking
is partly completely prevented. Tesla, of
Smiljan Lika, border country Austria-Han
gary, have invented Improvement Dy-
5 namo-Electric Machines, which the follow
ing specification.
In the drawings, Figure section a
commutator with asbestos insulating de
vice'; and Fig. For this pur
pose employ with the commutator bars
40 and intervening insulating material mica, as
bestos paper other insulating and prefer
ably incombustible material, which arrange
to bear the surface the commutator,
near and behind the brush. represents the commutator and
intervening insulating material; the
brushes, are sheets asbestns paper or
other suitable non-conducting material. 55
are springs, the pressure which may ad
justed means the screws g.
I prefer use asbestos paper cloth im
pregnated with zinc-oxide, magnesia, zirconia,
or other suitable material, the paper and 75
cloth are soft, and serve the same time to
wipe and polish the commutator; but mica or
any other suitable material may employed,
said material being insulator bad con
ductor electricity.
1885.
