Improvements relating to Electric Lighting Systems.
Year: 1899

page_text: Date of Application, 27th Sept., 1899
Complete Specification Left, 27th June, 1900-Accepted, 25th Aug., 1900
PROVISIONAL SPECIFICATION..
Improvements relating to Electric Lighting Systems.
We, ANDRÉ BLONDEL, of 41, Avenue de la Bourdonnais, Civil Engineer,
GUSTAVE WEISSMANN, of 3, Rue Chaptal, Civil Engineer, and ALFRED WYDTS, of
339, Rue des Pyrenees, Electrical Engineer, all of Paris, in the Republic of
France, do hereby declare the nature of this invention to be as follows:-
This invention relates to electric lighting systems and experience proves the
fact, which numerous tests have enabled us to recognise, that incandescent lamps
of low-voltage (20 volts for example). possess illuminating capacities superior to
lamps working with 110 volts said voltage being the tension ordinarily used in
distributing circuits for towns. The light of low-voltage lamps is whiter, and
the filaments being of larger section are better able to resist shocks.
But as a set-off, companies, in order to avoid the heavy costs incurred by the
installation of conductors, are obliged to lower to not less than 110 volts the
current they distribute to their consumers.
The result therefor, from these considerations, is that in practice the voltage
of the current distributed through the conductors in towns is too low from the
companys point of view while at the same time it is too high from the point of
view of yielding the best results in connection with the electrical apparatus
employed by the consumer.
Now our invention has reference to a mode of utilizing the current so as to
permit the practical employment of incandescent lamps with low voltage for high
tension circuits. Thus the improved system causes the aforementioned incon-
venience to disappear and permits for example to commercially use incandescent
lamps of 20 volts fed from alternating currents of 110 to 220 volts distributed
through the general conductors of a town or of a section.
Our invention consists in principally of interpolating after the meter of the
subscriber and between each lamp (or each group of lamps) and the cut-out con-
trolling the same, a small transformer with a closed magnetic circuit so calcu-
lated as to operate with full load when the lamp is alight, but completely cut-
out from the circuit when not in use. This small transformer lowers the voltage
of the main circuit from the conductors of the town (110 volt for example) to the
desired strength for its local use, the subscriber using low voltage lamps, (say
20 volts for example).
It will be readily understood that this invention is independent of any detail
arrangements in the transformers used as also with regard to the position
occupied by them in the conductors leading from each illuminating apparatus to
the cut-out controlling the same:
In order that our invention may be readily understood we have illustrated the
same diagrammatically in the accompanying drawings.
In carrying our said invention in practice a a denote the cables or conductors
of the distributing circuit to which is connected the meter e provided with cut-
outs bb. From these conductors internal circuits d d branch-off which feed
the electric lamps which may be arranged in an isolated manner as shown at e,

page_text: or in groups as shown at e¹ arranged for a group of two lamps, or as shown at e²
for a group of three lamps.
Each of these lamps, or each group of lamps is provided with a cut-out f and
with a smaller transformer g interpolated between the cut-out and the lamps.
In these conditions each transformer acts only when the lamp or group of
lamps to which it belongs is (or are) alight, but is cut out of circuit directly
the lamp or group of lamps is (or are) extinguished. Moreover each such trans-
former g, being calculated for the power absorbed by the lamp, works with full
load .e. giving its maximum current.
For example, if each lamp consumes 20 watts the transformer g of the lamp e
in an isolated case shown in the drawing, would be calculated for 20 watts, while
that of the group of lamps e¹ would be calculated for 2 × 20 = 40
watts and that of the group lamps 2 for 3 × 20 60 watts. It
is advantageous to place the transformers y as close to the lamps as is possible
with a view of shortening as much as possible the length of conductors of thick
wire which pass the current of 20 volts while the thin conductors a supply tho
current of 110 volts.
We would here point out that the use of a small transformer for each lamp
or each group of lamps presents a special advantage as compared with the use of
a single transformer for supplying the entire installation of the subscriber.
In the former case it is clear, as has been stated, that the transformers work
with full load and the conductors only consist of thick wire.
In the latter case, on the contrary, the transformer calculated for the entire
installation, does not work with full load except at very rare occasions when
all the lamps in this installation may be alight at one time so that generally its
working is very defective. Moreover the whole circuit of the subscriber would
have to be constructed of thick wire.
These considerations permit of the double result obtained by this invention
commercially considered, being clearly understood and by which companies are
enabled to increase the voltage tension of the current supplied by their conductors
while their subscribers may use lamps and apparatus working at a much lower
voltage.
We would again point out that we do not give any particular arrangement of
transformer and that our invention is absolutely independent of any detail
arrangements and we reserve the right to use any known type of transformer and
to arrange the same at any convenient point between the cut-out and the lamps,
for example in the box or casing or in the body itself of the cut-outs, or in the
support of the lamps themselves.
Dlh 1 1.
1000
Improvements relating to Electric Lighting Systems.
We, ANDRÉ BLONDEL, of 41, Avenue de la Bourdonnais, Civil Engineer,
GUSTAVE WEISSMANN, of 3, Rue Chaptal, Civil Engineer, and ALFRED WYDTS, of
339, Rue des Pyrénées, Electrical Engineer, all of Paris, in the Republic of
France, do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by
the following statement:-
Experience and numerous personal experiments have shewn us that incan-

page_text: descence electric lamps of low voltage (20 volts for example) possess a luminous
efficiency superior to that of lamps of 110 volts., which is the tension most usually
employed in town distributing circuits. The light given by lamps of low voltage
is whiter, and the filaments being of larger section resist shocks and vibration
better.
But, on the other hand, electric lighting companies, in order to keep the cost
of the distributing installation within reasonable limits, cannot reduce below
110 volts the current which they distribute to the consumers.
From these considerations it results that in practice the voltage of the currents
distributed through the town main is too low from the lighting company's point
of view, and at the same time too high as regards the efficiency of the electric
appliances employed by the consumers.
Our invention relates to a method of distributing electric currents which per-
mits of the employment of indescence electric lamps of low voltage in a practical
and commercial manner upon electric circuits of far higher voltage. This method
therefore obviates the defects above referred to and enables, for example, 20 volt
incandescence lamps to be successfully run by means of alternating currents of
from 110 to 220 volts passing through the mains of a town or district.
Our invention consists substantially in interposing, after the consumer's meter,
and between each lamp or each group of lamps, and the switch which directly
controls this lamp or group of lamps, a small transformer having a closed mag-
netic circuit reducing the voltage of the current in the desired proportion, this
transformer being selected in accordance with the consumption of the lamp or
group of lamps, and arranged in such a manner as to be inoperative when
uncharged but operative when fully charged, immediately the lamp or group of
lamps to which it is assigned is kindled, whilst it is entirely withdrawn from the
circuit when the lamp or group of lamps is extinguished. This small transformer
therefore reduces the voltage of the main circuit or town distributing main (which
is at 110 volts for example) to the voltage at which it is desired that it should
be used by each consumer for lamps of low voltage (20 volts for example).
I
It will be readily understood that our method is independent of the detail
arrangements of the transformers employed, and also of the positions which they
occupy upon the conductors passing from each illuminating appliance to the
switch which controls it.
These transformers should be constructed in such a manner as to be of as
small a volume as possible so that they may be concealed in the illuminating
appliances when the arrangement of these latter permits of it; with this object
we prefer to employ for our transformers a special method of winding consisting
in a single winding one part of which successively serves as primary and
secondary.
In order that our invention may be readily and clearly understood we have
represented it by way of example, in the accompanying drawing, in which:
Figure 1 is a diagrammatic view, shewing an arrangement by means of which
our method of utilising electric currents is carried into practice.
Figures 2 to 5 illustrate the application of our invention to different types of
illuminating appliances.
Figure 2 shows a form of application in which the switch is arranged outside
the illuminating appliance.
Figures 34 and 5 shew, on the other hand, the application of our invention to
different types of illuminating appliance such as lustres, brackets, office or table
lamps, within which the transformer is lodged.
Figure 6 shews the application of a transformer having a single winding.
Figures 7 and 8 shew two modifications in which the transformer is applied
to a group of three lamps.
Figures 9 and 10 illustrate two modifications in which the single winding acts,
throughout its entire length, successively as primary and secondary.

page_text: In these various figures similar letters of reference, are used to designate like.
parts.
In Figure 1a a are the line. wires of the distributing circuit upon which is
arranged the meter.b provided with switches c c. From this line à a leads the
interior circuit d d supplying the electric lamps arranged either separately, as e,
or in groups as, e¹, a group of two lamps, or ell, a group of three lamps.
Each of these lamps, or each of these groups of lamps, is provided with a
switch f and a small transformer g, interposed between the said switch and the
lamps.
Under these conditions none of the transformers operates, except when the
lamp or group of lamps to which it is assigned is kindled and it is placed out of
circuit immediately the lamp or group of lamps is extinguished. In addition
to this, each of the transformers g being selected in accordance. with the, energy
absorbed by the lamp, invariably operates with a full charge, that is to say in
giving its maximum output.
=
For example, if each lamp consumes 20 watts, the transformer g of the lamp e
in the case of the installation represented in the drawing will be calculated for
20 watts, whilst that for the group of lamps el will be 2 × 20 = 40 watts, and
that for the group of lamps ell 3 × 2 60 watts. Finally it is advantageous to
arrange the transformers in as close proximity. as possible. to the lamps in order.
to decrease as far as possible the length of the large wire conductors which
receive the current of 20 volts, whilst the fine conductors a and d carry the cur-
rent of 110 volts.
!
We would. point out that the application of a small transformer to each lamp,
or each group of lamps, presents a special advantage over the employment of a
single transformer serving the whole of the consumer's installation
In the first named arrangement, as we have seen, the transformers always
operate fully charged and only the conductors h are large wire conductors.
In the second arrangement, on the other hand, the transformer being selected
with regard to the entire installation, will only operate fully charged in the
comparatively rare event of the whole of the lamps being alight at the same
time, and consequently for the greater part of the time its efficiency will be poor.
In addition to this the whole of the consumers circuit must be of large wire.
We desire it to be distinctly understood that we do not here describe any special
form of transformer; our invention is in fact absolutely independent of all detail
arrangements, and we reserve the right to apply all known systems of trans-
former and to arrange the same at any suitable point between the switches and
the lamps, for example in the switch box or in the switches themselves, or in
the supports for the lamps.
In the arrangement represented in Figure 2, the internal wiring d which leads
from the cables a of the distributing circuit, traverses, as already explained, a
switch and the primary circuit. of the small transformer g, which is selected in
accordance with the consumption of the lamp e supplied by the secondary h of
this transformer.
The transformer g is preferably arranged at the top of the wall as near as
possible to the lamp, so as to diminish to the greatest possible extent the length
of the large section wire h.
When the arrangement of the illuminating appliance permits
former should be lodged within this latter, either in the rose
Figure 3) in the rose ; of a bracket (Figure 4) or in the foot
(Figure 5).
of it, the trans-
of a lustre (see
of a table lamp
This arrangement enables the transformer to be entirely hidden and consider-
ably diminishes the length of large section wire.
In order to decrease the volume of the transformers, we apply to these latter a
special method of winding consisting in a single winding, one part of which
serves successively as primary and secondary.
Assuming, for example, that with our method of utilising electric current it

page_text: is desired to establish a transformer for an incandescence lamp of 20 volts, the
primary current being 100 volts. also that calculation gives one thousand primary,
convolutions of a wire 5/10ths, of a millimetre'in diameter and two hundred con-
volutions secondary of a wire .8/10ths. of a millimetre in diameter.
It is well known that, in accordance with the usual methods, the primary and,
the secondary wire should be wound successively, that is to say, in the case.
assumed the thousand primary convolutions and then the two hundred secondary,
convolutions; it is therefore necessary to wind twelve hundred convolutions..
Our device, on the contrary, comprises only a single winding.
As shewn in Figure 6 of the drawing, the wire for winding consists of two,
different lengths; a length d successively serving as primary and secondary and
a length d which serves only as primary inducing circuit.
The lamp e is mounted upon a double wire which is in parallel upon the
length d.
The diameter of the wire and also the number of the convolutions constituting
the length d are equal respectively to those given by calculation for the induced
portion, in such a manner as to obtain an electro motive force of 20 volts, for.
example, between the terminals upon which the line wire of the lamp é is
mounted in parallel.
The wire of this length d', which is successively inducing and induced; should
have a diameter of 8/10ths. of a millimetre and that of the length d, which
only serves as the primary inducing circuit, will have a constant diameter of
5/10ths. of a millimetre, as previously mentioned.
Our method of winding therefore only comprises one thousand convolutions.
instead of one thousand two hundred as with the ordinary method: it therefore
economises two hundred primary convolutions thus effecting a large saving in
copper and in labour, whilst at the same time diminishing the volume of the
apparatus.
When the apparatus is intended to be used for transforming a current of 100.
volts for example, for supplying a group of lamps, three lamps of 20 volts for
example, these latter may be mounted either in parallel upon the two way wire
(Figure 7) or in series upon the portion of the winding which successively acts
as primary and secondary (Figure 8).
In the first case the number of convolutions of the length d' remains the same
as in the case of a single lamp, but the section of the wire will be equal to that
previously arrived at multiplied by the number of lamps to be supplied in the
present case the section would be tripled. It will thus be seen that, in this case,
an economy of two hundred convolutions of primary wire is effected as in the
previous case.
In the second case the diameter of the wire remains. the same as for one lamp.
that is to say eight tenths of a millimetre, but the number of convolutions of
the length is multiplied by the number of the lamps to be supplied, that is to
say tripled, the number of convolutions of the remaining length du being.equal
to the difference between the total number of convolutions of the primary portion-
(one thousand convolutions in the present case) and the number arrived at for the
secondary portion (six hundred convolutions).
In this second case an economy of six hundred convolutions of primary wire is
effected as compared with the usual method of winding.
Finally, if the appliance is intended to transform a current of one hundred
volts, for example, for supplying five lamps of 20 volts, for example, these latter
should preferably be mounted as sliewn-in Figure 9 with this arrangement, the
second length disappearing completely, the whole of the primary winding is
economised.
This latter device, is particularly advantageous for the supply upon sections of
110 or 200 volts of lamps of very small luminous intensity: lamps of one or two
candles for example..
It is well known that it is impossible to establish good lamps of such a low

page_text: luminous intensity below 110 volts, for example. Now by diminishing the volt-
age to 10 volts, for example, we have succeeded in obtaining excellent lamps of
one and two candles.
The transformer serving to feed 'these lamps should of course correspond to
the requirements; upon a current of 100 volts for example, there may be fed, by
means of one of these appliances, ten lamps of ten volts (of two candles or one
candle for example) or twenty lamps of five volts.
For this purpose the number of primary convolutions is calculated giving to
them such section as is necessary for feeding one lamp, the winding being
divided into as many sections as there are lamps to be fed.
In the first example, assuming that calculation has caused us to wind one
thousand six hundred convolutions, these convolutions are divided into sections.
of 160 convolutions. There will therefore be 10 sections of 160 convolutions
upon each of which may be arranged, as shewn in Figure 11, a ten volt lamp,
of two candles for example..
This combination is of the greatest importance in making lustres as it enables
a large number of sources of light of but feeble intensity to be obtained.
.
It will of course be understood that our method of utilising electric currents
may be carried into effect by means of all kinds of electric lighting appliances
comprising incandescence lamps, and that we reserve the right to combine one
with another the devices above specified, in any manner in accordance with the
various applications.
Our invention not only enables lamps of low voltage to be utilised, but also
permits electric lighting companies. to increase the tension of the currents which
they distribute without making it necessary for the consumer to employ lamps
of high voltage; thus they can support the tension of currents distributed at 110
to 220 volts, for example. By the application of our method, electric lighting
companies are enabled to light a much larger number of lamps without being
compelled to increase the section of their distributing cables.
It will also be understood that in the case of a consumer situated upon a
section in which continuous current is distributed, our system of utilisation will
be equally applicable, it being only necessary to first of all transform the con-
tinuous current into an alternating current by means of any suitable appliance.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is:-.
1. The method of utilising alternating electric currents, for the illumination
upon a commercial scale by means of electric lamps of low voltage (20 volts for
example) upon electric currents of high voltage (110 volts for example) consist-
ing in principle in interposing between each lamp or group of lamps and the
switch which directly controls it, a small transformer of closed magnetic circuit
lowering the voltage of the current in the desired proportion, this transformer
being selected in accordance with the consumption of the lamp or group of lamps
and arranged in such a manner as to be inoperative when uncharged but to
operate when fully charged immediately the lamp or group of lamps to which
it is assigned is kindled, whilst it is completely withdrawn from the circuit when
this lamp or group of lamps is extinguished substantially as described and shown
in the drawings
2. The application of the method of utilisation above described to different
types of electric illuminating appliances by means of incandescence lamps sub¹
stantially as described and shown in the drawings.
3. The application of a special method of winding to the transformers employed
in the method of utilising alternating electric currents as above described, this
special method of winding consisting in a single winding, serving, either upon
one portion of its length or for its entire length, successively as primary and
secondary, with the object of diminishing the weight and volume of these trans-

page_text: formers and thus permitting them to be readily concealed substantially as
described and shown in the drawings.
4. The application of our method of utilising alternating electric currents for
the supply upon a system of from 110 to 220 volts for example, of lamps of very
small luminous intensity, such as one or two candles for example substantally
as described and shown in the drawings.
Dated this 27th day of June 1900.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicants.