Improvements in Vacuum Tube Lighting.
Year: 1899

page_text: Date of Application, 24th Nov., 1899-Accepted, 18th Aug., 1900
COMPLETE SPECIFICATION.
Improvements in Vacuum Tube Lighting.
A communication from abroad by THE MOORE ELECTRICAL COMPANY, of New
York, City of New York, United States of America, Manufacturers of
Electrical Devices.
I, WILLIAM LLOYD WISE, of 46, Lincoln's Inn Fields, in the County of London,
Consulting Engineer and Chartered Patent Agent; do hereby declare the nature
of this invention and in what manner the same is to be performed to be particu-
larly described and ascertained in and by the following statement:―.
This invention relates to those systems of electric lighting wherein the lamps
consist of sealed glass tubes or other forms of receptacle containing rarefied air or
other gas, and are excited to luminosity by electric vibrations, waves, or distur-
bances of high frequency obtained from any desired source.
The object of this invention is to simplify the system and improve its efficiency,
to which end I propose to excite the tubes or lamps directly or indirectly (through
a transformer) by alternating currents or electro-motive forces produced by a
dynamo machine which is preferably specially constructed or organized to generate
an alternating impressed e.m.f. that rises and falls with great abruptness, or in
other words an e.m.f. in which the rate of change of each wave or pulse is
exceedingly high.
Graphically represented the best realization of such an alternating
ware
of e.m.f. would be a square topped wave of e.m.f. as represented in Fig. 6 of
the accompanying drawings, although in practice the wave obtained would
necessarily vary considerably from that form and be represented as more closely
following a true wave form owing to the effects of inductance or magnetic lag
in the generator.
This invention consists further, in an improved construction of dynamo
especially adapted for rotation at very high speed in order to produce a high
frequency alternating e.m.f. and which shall be free from the losses, heating and
other objections hitherto attaching to machines of this character.
This portion of the invention consists substantially in proportioning the polar
teeth or projections in the rotor and stator as herein before described, in such
manner that the total magnetic flux in the machine shall be at all times approxi-
mately the same.
This invention consists further, in certain details of construction and combina-
tions of apparatus whereby the special and general objects of this invention are
attained.
In the accompanying drawings, Fig. 1, is a sectional elevation of a form of
machine embodying this invention.
Fig. 2 is an end elevation of the rotor and stator.
Figs. 3, 4, 5, illustrate diagrammatically organizations of apparatus embodying
this invention.
Fig. 6 shows graphically the form of impressed e.m.f. which I aim to generate
in the dynamo machine used for directly exciting the vacuum lamps.

page_text: Referring to Figs. 1 and 2, the rotor or revolving armature of the machine
consists of a mass of iron 1, secured to a revolving shaft 2; and having a radially
projecting portion or flange, terminating in polar projections or teeth. 3. This
radially projecting portion of flange having projections or teeth preferably con-
sists of a series of discs having notches in their edges as shewn in Fig. 2, so as to
form the teeth 3, said dises being slid upon the mass of iron 1, and clamped in
position thereon by means of a clamp plate 5, which holds them against the
flange 4, projecting from the mass of iron 1.
The exciting coil or coils of the machine indicated at 6, surround the axis of
the rotor instead of being wound upon the polar projections. They are preferably
fixed and suitably supported in the stationary end plate or frame 7, of the
machine. The rotor revolves without having any attached wires upon its peri-
phery, and may be therefore run at very high speed. The laminated poles 3 thereof
are presented to the laminated poles 8, of the stator, said latter poles being
formed in the edge of a series of plates clamped in a ring or drum 9, of iron, and
all bolted to the iron end plate or frame 7, through which the magnetic circuit
is completed.
The poles 8 are wound with a series of generating coils connected up in any
desired fashion and supplying the alternating e.m.f. to the lamps. The polar
faces of the projecting poles 3, and 8, are provided with perfectly square corners
or projections, and are in as close propinquity as possible, the aim being to cause
the magnetic flux in the wound poles to rise and fall as abruptly as possible and
to thereby generate an. e.m.f. whose rate of change shall be as rapid as possible,
and thereby be better adapted to excite luminosity in the vacuum tubes.
Theoretically the form of varying e.m.f. best adapted to the purpose would be
as represented in Fig. 6, where each pulse is indicated as rising in E.m.f. from
zero to a maximum in a zero interval of time, which is of course, not realizable in
practice and would only be approximated by the machine described.
In any case, however, the air should be, in order to obtain the best results,
to so construct the dynamo as to produce an e.m.f., each pulse of which will
rise in potential with great abruptness, and this is the object of constructing the
polar projections with the square corners as shown. As will be seen the number
of poles in stator and rotor respectively is different, so that there are provided
intermediate poles (wound) in the stator in which there is alternately a magnetic
flux and cessation of magnetic flux, but the lengths of pole faces in the rotor are
such as to extend from the middle of one stator pole to the middle of the next,
so that as the flux in one is diminished by the rear portion of the rotor pole
uncovering a stator pole, the flux in the next pole will correspondingly increase,
thus keeping the total flux in the magnetic circuit of the machine constant and
avoiding thereby to a very great extent the losses from hysteresis and heating.
In the diagram, Fig. 3, I show an organization of apparatus embodying this
invention and in which the machine already described is especially useful.
The vacuum tube lamps indicated by the numeral 11, are connected across the
circuit wires leading from the alternating current dynamo 10, and are in direct
conducting connection therewith, so as to receive the impressed electro-motive
forces generated therein of high frequency and to be thereby rendered luminous.
In practice good results may be obtained by using a frequency of 800 periods
per second for the production of which the machine already described is especially
suited. A voltage in the machine itself of as low as 2000 volts may be satis-
factorily employed.
The vacuum tubes themselves are furnished with conducting caps at their ends
which caps may be of tin foil cemented to the tube, or may be conducting paint
or cement embodying graphite or other good conductor. The tubes thus formed
give considerable capacity to the circuit, and permit the employment of high
resonance effects either with or without the use of an artificial condenser added
to the circuit, as indicated at 13. At 12, is indicated an adjustable inductance
placed between the circuit wire leading to the lamps and the point of connection

page_text: of the condenser. This adjustable inductance may be employed for tuning the
circuit of lamps to resonance with the period of impressed e.m.f., thereby giving
increased luminous effects in the lamps.
In the modified arrangement indicated in Fig. 5, the lamps are indicated as
connected with the machine 10, through the potential raising converter or trans-
former 14, the arrangement being in other respects substantially the same as in
Fig. 3, in that the alternating e.m.f.'s generated by the dynamo are the exciting
c.m.f.'s for the lamps directly applied in Fig. 3, but indirectly by induction and
raising of potential in Fig 5.
In the latter arrangement, the potential of the machine may be only 100 volts
and the converter 14, be potential raising in the ratio of one to twenty, so as to
give 2000 volts on the lamp circuit.
Fig. 4 shows a modified arrangement wherein the converters 14, have their
primaries connected in multiple to the wires leading from the machine, and their
secondaries connected in series with the lamps as shown. each lamp being inter-
posed between two secondaries.
While I have shown one form of machine adapted to produce a suddenly
varying e.m.f. and have described the same as entering into the organizations of
apparatus shown in Figs. 3, 4, and 5, I do not wish to be understood as limiting
myself to the use of that form in those organizations.
Having now particularly described and ascertained the nature of this said
invention, and in what manner the same is to be performed, I declare that what
I claim is:
1. In a system of vacuum tube lighting, the combination with the tubes to be
excited, of an alternating current generator in direct conductive or inductive
connection therewith, and organized as described to produce an alternating
impressed e.m.f. of abruptly changing value.
2. In an alternating current dynamo, a rotor consisting of a revolving mass of
iron provided with a fixed exciting coil surrounding the axis on which the rotor
revolves, and having radially extending polar projections presented to the poles
of a stator, the iron of which is extended around to the opposite end of the rotor
to complete the magnetic circuit, as and for the purpose described.
3. In a dynamo electric machine, a rotor and stator having polar teeth or
projections the length of whose opposing faces are proportioned as described
to give a constant magnetic flux in the machine.
4. In a dynamo electric machine, a rotor and stator having polar teeth or
projections of one element of length sufficient to extend from the middle of a
pole of the other element to the middle of a succeeding pole and across the
intervening space or spaces.
5. A vacuum tube lighting apparatus comprising in combination an alternating
current dynamo whose rotating element consists of a mass of iron terminating in
unwound polar projections or teeth which in their rotation act upon suitable
generating coils, and lamps consisting of glass tubes or other forms of receptacle
containing only rarefied air or other gas and provided with exterior conducting
caps or electrodes connected directly or indirectly with the generating coils
of the machine, as and for the purpose described.
6. An electric lighting apparatus comprising an alternating dynamo whose
rotor consists of a revolving mass of iron terminating in unwound polar teeth or
projections which operate upon fixed generating coils, a transformer whose
primary is joined to the said generating coils, and a secondary for said trans-
former joined to lamps which consist of sealed glass tubes or other forms of
receptacle containing rarefied air or other gas, and provided with exterior con-
ducting caps or electrodes.
7. In an electric lighting apparatus, the combination of an alternating current
dynamo, electric lamps consisting of sealed glass tubes or other forms of recep-

page_text: tacle containing rarefied air or other gas and provided with conducting caps or
electrodes, the lamps being connected directly or indirectly with the dynamo so
as to be excited by the alternating e.m.f. thereof, and an adjustable inductance
connected to the circuit of the machine and lamps.
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C.
Chartered Patent Agent.