A Method of and Means for Regulating the Supply of Current for Illuminating Bodies or Filaments composed of Second-class Conductors (Electrolytes)
Year: 1899

page_text: Date of Application, 20th Mar., 1899 -Accepted, 10th June, 1899
[Communicated from abroad by ALLGEMEINE ELEKTRICITÄTS GESELLSCHAFT, of
Schiffbauerdamm, 22, Berlin, Germany.]
A Method of and Means for Regulating the Supply of Current for
Illuminating Bodies or Filaments composed of Second-class
Conductors (Electrolytes)
I, VICTOR ISIDORE FEENY, of 60, Queen Victoria Street, in the City and 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 particularly described and ascertained in and by the following statement:-
Illuminating bodies or filaments composed of second-class conductors (electro-
lytes) cannot be directly introduced into a circuit or system, but absolutely require
a special resistance, since they do not conduct as metals but as electrolytes.
With metals having an unimportant temperature co-efficient, as for example,
Kruppine, manganine, etc., it is well known that, according to Ohm's law, the
potential difference at the terminals varies proportionally to the strength (or
intensity) of the current. With metals having a considerable temperature
co-efficient, for instance, iron, nickel and platinum, that is to say with such
as acquire greater resistance with increased temperature, the potential difference
increases more, with an increased strength of the current, than would be neces-
sarily the case according to Ohm's law. Electrolytes on the contrary have the
property that, with an increase of temperature, the resistance diminishes, so that,
as occurs, for example, with illuminating bodies composed of second-class con-
ductors, the potential difference does not increase with increasing current inten-
sity but is often actually diminished. If, therefore, such an illuminating body
be placed direct in the circuit, upon an increase of current in such circuit or
net-work (variations of potential being unavoidable in any area or net-work) the
illuminating body becomes fused, as, in consequence of the constant diminution
of the resistance, the current intensity steadily increases. For this reason, the
introduction of a special resistance hereinafter described, is necessary.
In order to reduce the loss of voltage in the resistance to the smallest possible
per-centage, it has been found necessary to employ a substance having the highest
possible temperature co-efficient, such as nickel, iron, platinum, or metal alloys
possessing similar properties, which expand rapidly under varying intensity of
current. Whilst, hitherto, resistances made of such metals, or of alloys having
similar properties, have been avoided in practice, owing to the rapid increase of
the resistance upon increasing temperature, being an extremely objectionable
quality for the usual purposes, in the present case, the employment of metals
with a high temperature co-efficient is extremely desirable. Resistances of the
kind however have the disadvantage that when the current is put in circuit the
intensity of the current running through them is at first considerably greater
during some seconds than subsequently, when the wire has acquired a greater
resistance through being heated.

page_text: This disadvantage is apparent if such a substance be employed as a resistance
for an illuminating body of second-class conducting material, since immediately
after the illuminating body has begun to glow, the current passing through is at
first abnormally large, in consequence of which the support or core for the illu-
minating body, or the filament itself, is endangered.
The present invention consists accordingly in the fact that the resistance is
made of conducting materials having a high temperature co-efficient, and heated
immediately before the illuminating body or filament begins to glow. The
arrangement of this resistance must be such that the resistance will be heated
during the preliminary heating of the illuminating body or filament.
If the exciting of the second-class conductor be effected by means of a flame
(Bunsen burner, lighted match, spirit-lamp etc.) it is advisable to arrange the
resistance so near to the illuminating body, that it may be subjected simultane-
ously to a preliminary heating by means of the flame or burning gas. This
process can be employed in a modified form in lamps where the excitation is
electrically effected, the resistance being arranged as near as possible to the elec-
trical heating body or coil. Other methods can, however, be adopted; for
instance, the resistance can be introduced in the conductor serving for both the
illuminating body or filament. and the heating body or coil, so that, being
traversed by the heating current, it can be thereby heated and brought to a high
degree of resistance, before the illuminating current passes through it.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is-
(1). A method of regulating the supply of current for illuminating bodies or
filaments composed of second-class conductors, the distinguishing feature of which
is that the resistance is formed or made of a material having the highest possible
temperature co-efficient and is heated prior to the glowing or lighting-up of the
illuminating body or filament, substantially as described.
(2). A means for carrying out the invention claimed under Claim 1, the dis-
tinguishing feature of which is that the heating apparatus for exciting the illu-
minating body is simultaneously employed for preliminarily heating the resistance
substantially as described.
(3). A means for carrying out the invention claimed under Claim 1, the dis-
tinguishing feature of which is that the resistance for the illuminating body or
filament is simultaneously employed in the same capacity for the heating body,
with the view of the resistance being heated by means of the heating current, sub-
stantially as described.