Improvements in Arc Lamps.
Year: 1890

page_text: Date of Application, 7th Nov., 1890
Complete Specification Left, 23rd July, 1891-Accepted. 12th Sent
1801
PROVISIONAL SPECIFICATION.
[Communicated from abroad by Messrs. SIEMENS & HALSKE, of Berlin, in the
German Empire, Electrical Engineers.]
Improvements in Arc Lamps.
We, SIEMENS BROTHERS & CO. LIMITED of 12 Queen Anne's Gate, West-
minster, in the County of Middlesex, Electrical Engineers, do hereby declare the
nature of this invention to be as follows:--
In order to render are lamps applicable on electric light distributing networks in,
which a greater potential difference is used than is required for ordinary arc lamps,
it was hitherto necessary to reduce the excessive tension by means of resistances, or
to arrange several lamps in series, which were then dependent upon each other, that
is to say, which required all to be in operation and out of operation at the same
time.
The present invention consists in arranging two or more pairs of carbons in an arc
lamp in such manner, that the same current has to pass through them in series.
Between each pair of carbons an arc is formed, and as a certain potential difference
is required for each arc, the total potential difference of the lamp can be increased
as may be desired, by increasing the number of pairs of carbons.
According to one arrangement of lamp for this purpose, two pairs of carbons are
employed, the current being passed first from the upper positive to the lower
negative carbon of the one pair and then from the lower positive to the upper negative
carbon of the other pair, forming the are between each pair. Preferably
however, specially in the case of continuous currents, both the upper carbons are
made positive, so that the current passes from the negative lower carbon of the
first pair to the upper positive carbon of the second pair, the current being thus
made to pass in the same direction through each pair.
When alternating currents are employed, the relative positions of the positive and
negative carbons in each pair is of course immaterial.
According to another arrangement three pairs of carbons are employed, the
current being made to pass from the lower negative carbon of the first pair to the
upper positive carbon of the second pair, from the lower negative carbon of which
it is again led to the upper positive carbon of the third pair.
Or the current may be passed simultaneously through the upper positive carbons
of the two first pairs and then from both negative carbons to the positive carbon of
the third pair. Or there may be four pairs of carbons, the current being passed
imultaneously through the first and second and then simultaneously through the
hird and fourth. In this way a great variety of groupings may be effected.
The regulation of a lamp of the above description can either be effected by
egulating all the carbons simultaneously or each pair of carbons, or each group of
airs may have a separate regulating mechanism.
Assuming the case where two pairs of carbons are controlled by the same
egulating apparatus, then in order to insure an equal consumption of both pairs the
ollowing must be observed.
The regulating mechanism will adjust the carbon holders in such manner that the
im of the two arcs remains practically constant. If now from some cause the arc
the one pair has become longer than that of the other, the shorter arc will always
e less than the normal length, and the longer arc more than the normal length.
s however the carbons of an arc lamp consume more quickly the longer the arc,
ere will always be a tendency to increase the difference once established between
e two arcs.
To obviate this defect the following arrangement may he omnloved.

page_text: the arrangement to be that in which the two positive carbons are at top, and are
simultaneously fed forward by the regulator so as to maintain the sum of the two
arcs constant; the holder of the two negative carbons is mounted as a balance
beam, and has attached to each end the armature of an electro magnet.
The coil of the electro magnet on the side where the first carbon pair is situated
is coupled in parallel to the arc of the other pair, while the coil of the other electro
magnet is coupled in parallel to the arc of the first pair.
Thus on, say, the arc of the second pair becoming greater than that of the first
pair, the electro magnet that is coupled in parallel with the former and acts upon
the latter will be traversed by an increased current and in being thereby made to
attract its armature with a greater force than the other electro magnet attracts its
armature, it will cause the pivotted lower carbon holder to be tilted over so that the
distance between the carbons of the first pair is increased and that between the
carbons of the second pair decreased. The angular movement of the carbon holder
is so limited that it will continue under the attraction until the arc of the first pair
of carbons will be slightly greater than that of the second pair. The consequence
of this will be that the arc of the first pair will now gradually increase, until the
above described action will take place in the reverse direction, and so on, a periodical
oscillation of the lower carbon holder being thus effected until the carbons are
entirely consumed. The above described electro magnetic adjustment may of
course be applied to the upper instead of the lower carbons or to the regulating
mechanism.
Dated this 7th day of November 1890.
ABEL & IMRAY,
Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements in Arc Lamps.
We, SIEMENS BROTHERS & Co. LIMITED, of 12 Queen Anne's Gate,
Westminster, in the County of Middlesex, Electrical Engineers, 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:-
In order to render are lamps applicable on electric light distributing networks in
which a greater potential difference is used than is required for ordinary arc lamps,
it was hitherto necessary to reduce the excessive tension by means of resistances,
or to arrange several lamps in series, which were then dependent upon each other,
that is to say, which required all to be in operation and out of operation at the
same time.
The present invention consists in arranging two or more pairs of carbons in an
arc lamp in such manner that the same current has to pass through them in series.
Between each pair of carbons an arc is formed, and as a certain potential difference
is required for each arc, the total potential difference of the lamp can be increased
as may be desired, by increasing the number of pairs of carbons."
Figs. 1 to 5 of the accompanying drawings shew diagrammatically various
arrangements which may be employed for carrying out the said invention.
In the arrangement at Fig. I there are two pairs of carbons, the current being
made first to pass into carbon No. 1, forming a luminous arc between 1 and 2;
from carbon 2 it passes to carbon 3 and forms between 3 and 4 the second arc.
Generally however, the arrangement at Fig. 2 will be preferable, in particular
when a continuous current is used. In this case the first arc is formed between 1
and 2, as before, but the current is then passed from carbon 2 up to carbon 4, whence
it passes over to 3 in forming the second arc.
Generally speaking, in lamps using continuous currents, the current will be
arranged to pass in the same direction through both pairs of carbons, whereas in

page_text: alternate current lamps the simplest available arrangement may be chosen, irrespec-
tive of the direction of the currents.
Figure 3 shews an arrangement with three pairs of carbons, the current being
made to pass consecutively through all three pairs in the same direction, as
indicated.
In Figure 4 there are two groups of carbons, each consisting of two pairs, the
current being made first to pass simultaneously through the two pairs of the first
group, thus producing two luminous arcs, and then simultaneously through the two
pairs of the second group, producing two further luminous arcs. Or the two pairs
of each group might also be connected in series instead of in parallel as at Fig. 1
so as to cause the current to pass in series and alternately in contrary directions
through the four sets of carbons. A greater number than two groups of carbons
may be employed, and they may be coupled up in various other ways.
Fig. 5 shews an arrangement in which the current first passes through a group of
two pairs of carbons, and then through a single pair.
Various other combinations of pairs or groups of carbons may be arranged for
operating according to this invention, the essential feature being in all cases that
the current is made to pass in series through two or more pairs of carbons so as to
produce simultaneously two or more luminous arcs in one and the same lamp.
The regulation of a lamp of the above description can either be effected by
regulating all the carbons simultaneously or each pair of carbons, or each group of
pairs may have a separate regulating mechanism.
Asssuming the case where two pairs of carbons are controlled by the same
regulating apparatus then in order to insure an equal consumption of both pairs the
following must be observed.
The regulating mechanism will adjust the carbon holders in such manner that the
sum of the two arcs remains practically constant.
If now from some cause the arc of the one pai has become longer than that of
the other, the shorter arc will always be less than the normal length and the longer
are more than the normal length. As however the carbons of an arc lamp consume
more quickly the longer the arc, there will always be a tendency to increase the
difference once established between the two arcs.
In order to obviate this defect the arrangement shewn diagrammatically at Fig. 6
may be employed.
The current is made to pass through the carbon pairs 1, 2 and 3, 4 say in the
direction 1. 2. 4. 3. The carbons I and 4 are fixed in the upper carbon holder K o,
which can be raised and lowered in such a manner that the sum of the two luminous
arcs generally remains the same.
The lower carbon holder K u is arranged as a balance beam on the support S in
such manner that it can turn through a certain angle. To each end of the carbon
holder is attached the armature A1 A2 of electro-magnets E1 E2 fixed below, the
electro-magnet E¹ being made to act upon the armature A' which controls the
arc 4, 3, and it is arranged in parallel with the arc 1, 2.
The electro-magnet E2 acts on the armature A2 which controls the arc 1, 2 and it
is connected in parallel with the arc 4, 3.
The action of this arrangement is as follows. As soon as, say, the arc 4, 3
becomes longer than the arc 1, 2, the electro-magnet coil E' which is in shunt circuit
to the arc 4, 3 will be subject to a greater tension than the coil of electro-magnet E'.
The difference in the length of the two arcs and consequently that of the two
tensions will go on increasing until the attraction exerted by the electro-magnet E²
upon its armature A² sufficiently exceeds the attraction exercised by E' upon A¹ to
cause the position of the carbon holder Ku to be changed. As however the
attraction of an electro-magnet does not alone depend upon its excitation, but also
pon the distance of the armature, the difference between the attractions exerted
by the two electro-magnets will continue to increase as the armature A² approaches E²,
nd the carbon holder will consequently tilt over on that side until its limit of
notion is reached. This limitation is so arranged that if the are 4, 3 was in the

page_text: first instance greater than 1, 2, then after the tilting over, the arc 1, 2 will be
slightly greater than 4, 3. The consequence hereof will be that the arc 1, 2 will
now gradually increase until the difference in the action of the electro-magnets has
become sufficiently great to cause the tilting over of the carbon holder in the
contrary direction and this alternate action will continue until the carbons are
entirely burnt down. The difference between the length of the two arcs can con-
sequently never be greater than is permitted by the above sensitive device.
This regulating mechanism can of course be applied to the upper carbon
holder o instead of to the lower one, or it may be combined with the regulating
mechanism R of the lamp in any suitable manner.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what we
claim is
1. An electric arc lamp wherein two or more pairs or groups of pairs of carbons
are so arranged in combination that the current passes through them so as to
produce simultaneously two or more luminous ares, the total potential difference of
the lamp being equal to a multiple of the potential difference of a single pair of
carbons, each pair of carbons or each group of pairs being either controlled by a
separate regulating device, or several groups of pairs or all the pairs of carbons
being controlled by a single regulating mechanism, substantially as described.
2. In an electric arc lamp such as is referred to in the preceding claim, the use,
for ensuring the simultaneous consumption of all the carbons, of a mechanism whereby
when the one luminous are becomes to a certain extent longer than the other, the
positions of the carbons are altered by the differential action of the current upon
electro-magnets or solenoids, which control the carbons, thereby causing the arc
which was previously the shorter one to become the longer one, such mechanism
being employed in combination with any known regulating mechanism for maintaining
constant the sum of the lengths of the arcs, substantially as described.
Dated this 22nd day of T1. 1901
ABEL & IMRAY,
Agents for the Applicants.