A New or Improved System of Electric Lighting and Apparatus therefor.
Year: 1888

page_text: PROVISIONAL SPECIFICATION.
A New or Improved System of Electric Lighting and Apparatus
therefor.
I, JOHN GRICE STATTER of Alliance Engineering Works West Drayton
Electrical Engineer do hereby declare the nature of this invention to be as
follows:-
My invention relates to a system of Electric Lighting whereby I am able to
effect such by incandescent lamps when arranged in series with safety and economy.
I effect this by employing alternating currents of electricity generated by an
alternating constant current dynamo which currents are transmitted through trans-
formers arranged in series and the secondary circuits of which transformers each
contain one or a few incandescent lamps. I may adapt the transformer to the base
of a lamp or to its holder and I may use switches which when placed in the primary
or main circuit short circuit one or more of the transformers but which do not open
the said circuit. I may maintain the current from, the dynamo constant by
employing an automatic electric regulator to alter the position of the brushes on the
conimutator of the exciter the said regulator being fed and actuated by the current
from the alternating current machine and not by that from the exciter.
The use of automatic cut outs to preserve the continuity of the circuit in the event
of a breakage of a lamp or lamps is unnecessary in my system.
.. A
1 1000
J. G. LORRAIN, M.S.T.E., M. Inst. M.E.,
Consulting Electrician and Patent Agent,
Norfolk House, Norfolk Street, London, W.C.,
Agent for Applicant.

page_text: A New or Improved System of Electric Lighting and Apparatus
therefor.
I, JOHN GRICE STATTER, of Alliance Engineering Works, West Drayton,
Electrical Engineer, 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:-
My invention relates to a system of electric lighting whereby I am able to work.
incandescent lamps in series with safety and economy, and even when the number
of such incandescent lamps in series is very large. At the same time I am able to
obtain such a nicety of regulation that the consumption of energy is practically
proportional to the number of lamps alight.
I effect this by employing alternating currents of electricity generated by an
alternating constant current dynamo, which currents are transmitted through trans-
formers arranged in series, and the secondary circuits of which transformers each
contain one or a few incandescent lamps. In figure 1 I illustrate diagrammatically
the arrangement which I have found most convenient for the carrying of my
invention into effect. In this figure A is an alternator of any ordinary type, having
its field magnets excited by a direct current obtained from an independent exciting
machine, and being such that a variation in the exciting current supplied to its field
magnets by the said exciting machine will cause a variation of the electromotive
force produced by the alternator. This exciting current is furnished by the direct
current dynamo or exciter C whose pole pieces are modified after the manner set
forth in the Complete Specification accompanying my Letters Patent No. 2825 of the
year 1887 (it being understood that the exploration curves, and consequently the
shaping curve, from which the pole pieces are modified, are to be obtained whilst
the machine is being run as herein set forth), so that the brushes may be moved
through a considerable angular distance round the commutator without producing
sparking, a progressive forward movement of the brushes causing a corresponding
decrease of current. I cause the brushes to be moved on the commutator automatically
by a regulator G. The said regulator G is one of the kind described in the Complete
Specification accompanying the Letters Patent granted to Sydney Lynton Brunton.
and myself No. 13,320 of the year 1887, but whose electromagnet or solenoid which
serves to determine the direction and extent of the movement has its coil connected
in series with the main circuit of the alternator, and whose armature or core is
laminated so as to be suitable for alternating currents. By this arrangement it will
be seen that the current given out by the alternator determines the amount of
current given out by the exciter and since the electromotive force of the alternator,
and hence the amount of its current, other things remaining the same, depends upon
the amount of the current given out by the exciter, I obtain an alternator which has
a variable electromotive force but a constant current when working into a variable
resistance. I am thus able to keep the main circuit supplied with a current whose
strength or quantity shall be constant, but whose electromotive force will vary with
the resistance of the said circuit, that is to say, with the number of lamps alight.
In this circuit M, each of the circles L represents an incandescent lamp with its
transformer, as is more clearly shown in a diagrammatic manner in figure 2, which

page_text: figure I shall describe hereinafter. T T¹ are the terminals of the main circuit M,
and X X the terminals for the leads N of the exciter. B B' represent the brushes.
In figure 2 I show diagrammatically the parts symbolically represented by the circles L
in figure 1. O is a transformer whose primary coil of is in series with the main
circuit M, and whose secondary coil o² is in circuit with the high resistance incan-
descent lamp P. Q represents a switch which short circuits or cuts out the
transformer, but which does not open the main circuit; and this is the switch which
is employed to turn tho lamp off or on.
:
Having thus described a typical manner of carrying my invention into effect,
namely that which I have found most convenient for my purpose, I would here
remark that considerable modifications may be introduced without departing from
my invention.
For example, instead of the lamp P being a high resistance
incandescent lamp it might be a low resistance incandescent lamp and if the current
required for such were larger than that transmitted through the main circuit the
secondary coil of the transformer would then be of thicker wire than that in the
primary instead of being as shown in figure 2. Any convenient form of alternating
current transformer will suit my purpose. Again the switch Q might be in the
secondary circuit and then serve to cut out the lamp P: but it would do so not by
short circuiting as in the case shown in the figure, but by causing the secondary
circuit to be broken or opened. The regulator G need not necessarily be of the kind
cited, as there are other well known forms of regulator which would answer the
purpose, provided they were actuated by the current in the main circuit as herein-
before described. Again the constancy of the current produced by the alternator
need not necessarily be produced by the employment of an exciting current generated
by a direct current machine having pole pieces modified in accordance with my
Letters Patent No. 2825 of the year 1887, as any other known method of automatically
keeping the current given out by an alternator constant would answer my purpose.
It will be seen then that the essence of my invention, in so far as it applies to a
system of Electric Lighting, lies in the employment of an alternator producing
automatically a constant current, the said constant current being passed through
transformers arranged in series, the secondary circuits of the said transformers each
containing one or a few incandescent lamps.
In the typical method of carrying my invention into effect which I have described,
I mention only one lamp as being in the secondary circuit of each transformer; and
I have elsewhere in this Specification stated that the said secondary circuits may
contain a few incandescent lamps. I desire it to be understood that, when speaking
of a few incandescent lamps in the secondary circuit, I refer to a group of lamps
constituting one centre of light as it were, and which group of lamps would under
ordinary circumstances be turned off and on by one switch. If however a large
number of lamps be arranged so as to be all turned off or on together, then my
invention would be equally applicable, just as in the case when a few lamps in one
group are employed; and this would practically be equivalent to a few lamps as
ordinarily understood and such large number of lamps might even be arranged in
parallel, but the said lamps could then not be conveniently turned off and on
individually, unless what are known as choking coils or the like were employed.
:
I desire it to be understood that that part of my invention consisting of the
apparatus for producing a current of constant quantity or strength but of variable
electromotive force as aforesaid is applicable to such cases as that wherein low
resistance incandescent lamps are worked in series without transformers, but in which
automatic cut outs are employed for each lamp.
Although such part of my invention is so applicable I prefer to employ such part
in connection with transformers as hereinbefore described, as by doing so a great
advantage is obtained, the employment of a large number of cut outs in series being
very risky and otherwise objectionable.
My invention is more particularly applicable to street lighting, though not
exclusively to such, and to demonstrate its utility I will describe its application to a
particular case. It is let us say desired to light a line of Boulevards two miles in

page_text: circumference by means of fifty candle power lamps placed twenty five yards apart.
One hundred and forty one lamps will be required and will each take fifteen volts
and ten amperes. By my system each lamp will be worked by a small independent
transformer. The primary coil of this transformer will take a current of 30 amperes
and 5-3 volts. All the primary coils will be connected in series with the alternator
at the generating station (which may be at a spot near to the line of Boulevards);
and the line wire and the primary coils of the transformers will form an uninterrupted
circuit capable of being very carefully insulated, and always good, whatever may
happen to the lamps in the circuit of the secondary coils, whilst the action of the
regulator will prevent any chance of the primary coils being burnt up.
30 amperes
being a very convenient current easily carried by a light cable, I choose this amount
for this particular case. The difference of potential at the station for 141 lamps
will be only 747 3 volts for the lamps, and for 2 miles of single cable say 52.7 volts,
making 800 volts in all. In case of the breaking of any of the lamps the counter
electromotive force of the transformer, normally 53 volts per transformer, falls, and
the current tends to increase. This increased current passing through the regulator
causes the brushes to be moved forward, and less current to be given out by the
exciter and consequently the electromotive force of the alternator falls, and the
current in the line is brought back to the normal amount. As very high insulation
may under this system be obtained on the line, as high an electromotive force as
10,000 volts might be safely used at the station. Such a plant at 30 amperes would
illuminate 1886 fifty candle power lamps, or 3080 thirty two candle power lamps;
and by using 60 amperes in the primary, and still no more than 10 amperes in the
secondary, no less than 6160 lamps of thirty two candle power could be maintained
with an electromotive force of 10,000 volts only. It will be seen therefore that as
a series system a very large number of lamps may be conveniently worked on one
circuit.
Having now particularly described and ascertained the nature of, my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
1. The new or improved system of electric lighting characterised by the employ-
ment of alternating currents generated by an alternating constant current dynamo
the said currents being transmitted through transformers whose primary circuits are
arranged in series and whose secondary circuits each contain one or a few incandescent
lamps substantially as set forth.
2. The new or improved apparatus for electric lighting consisting in the combination
of a source of constant alternating currents and a number of transformers whose
primary circuits are connected up in series with the main circuit and whose
secondary circuits each contain one or a few incandescent lamps substantially as
set forth.
3. In the new or improved system of electric lighting herein set forth the
employment of a source of constant alternating currents substantially as described.
4. The new or improved apparatus for electric lighting consisting in an alternator
whose field magnets are excited by a current from a direct current exciter this exciter
having pole pieces modified as aforesaid and having its brushes automatically moved
upon the commutator by a regulator actuated by the current in the main circuit of
the said alternator substantially as set forth.
J. G. LORRAIN, M. Inst. E.E., M. Inst. M.E.,
Norfolk House, Norfolk Street, London, W.C.,
Agent for Applicant.