detail section the
field-magnets exhibiting the plan winding. For example, may use generator
which produces ten thousand more alter
nations current per second. Fig.
Application filed October 1,1890. easy, for instance, to
obtain this manner three hundred and
seventy-five four hundred poles ma
chine that may safely driven speed 95
fifteen hundred sixteen hundred revolu
tions per minute, which will produce ten
thousand eleven thousand alternations of
current per second. This
noise probablydue the rapidly alternating-
heating and cooling and consequent expan-
25 sion and contraction the gaseous matter
forming the arc which corresponds with the
periods impulses the current, for have
succeeded abating and producing quiet
and smoothly-acting lamps increasing, per
30 unit time, the number alternations or
pulsations the current producing the arc
to such extent that the rate the vibra
tions changes the arc producing the
noise approximately equals exceeds that
35 which generally regarded the limit of
audition. 5,carrying said wire
around the annulus form many layers
as desired.
METHOD OPERATING ARC LAMPS.
Figure view the generator side
elevation. 55
an enlarged sectional detail the armature
and field. Fig.
This invention consists improved
to method operating electric-arc lamps which
are supplied with alternating pulsating
currents. Arc lamps are
shown diagram connected series 10c
with the machine Fig. Serial No.
It has now become common practice to
run arc lamps alternating pulsating as
15 distinguished from continuous currents; but
an objection such systems exists the fact
that the arcs emit pronounced sound, vary
ing with the rate the alternations pulsa
tions current, but under any circumstances
20 constituting objectionable and disagree
able feature, for which heretofore effective
remedy has been found proposed.
A annular magnetic frame supported
by the cross-bars brackets provided with 60
feet upon whicli the machine rests. The coils are con
nected together series, and these terminals
N carried through the hollow shaft con
tact-rings from whence the currents are
taken off brushes this way ma- 90
chine with very large number poles may
be constructed.
NIKOLA TESLA, NEW YORK, Y.)
To all whom concern:
Be known that sub
ject the Emperor Austria-11ungary, re
siding New York, the county and State
5 New York, have invented certain new and
usefulImprovements Methods Operating
Arc Lamps, which the following speci
fication.
Owing the very large number and small
size the poles and the spaces between them,
I apply the exciting field coils winding
an insulated conductor zigzag through the 70
grooves, shown Fig. Pins are set the
sides the ring and the coils Mare wound
over the periphery the armature-structure 85
and around the pins. 75
For the armature employ spider cir
cular frame driving-shaftH, mounted
in bearings the brackets This spider
carries ring turned down, except its
edges, form trough-like receptacle for 80
mass fineannealed iron wires which are
wound the groove form the core proper
for the armature-coils. this way the pole-pieces D
will energized with alternately opposite
polarity around the entire ring.
There are number ways which the
current may varied rate exceeding
the limit audition, but probably the most
45 practicable known present the
use alternating-current generator with
a large number poles, and specially con
structed for the purpose. The
interior the annulus provided with a
large number projections pole-pieces D. 447,920, dated March. 366,734, (Nomodel. Fig. such case
the periodical heating and cooling the arc
40 would occur with such rapidity produce
little perceptible effect upon the ear.
These may formed applied variety
of ways—as, for example, milling trans- 65
verse grooves E.nited States Patent Office. 10,1891.
SPECIFICATION forming part Letters Patent No. enlarged view, side
elevation, part the machine. Such generator, for
the purpose the illustration this case, I
50 have shown the accompanying drawings. Fig. such current
be applied running arc lamps, the sound
produced the arc becomes practically
inaudible,for increasing the rate of'cEange
. vertical cross-section
of the same with diagram the circuit-con
nections
