IMPROVEMENTS IN ELECTRIC ARC LAMPS
Year: 1884

page_text: COME LEIE
DELICATION.
I THOMAS JOHN HANDFORD of 42 Southampton Buildings in the County of
Middlesex Patent Agent, do hereby declare the nature of this invention for
"IMPROVEMENTS IN ELECTRIC ARC LAMPS," and in what manner the same. is to be
performed, to be particularly described and ascertained in and by the following
statement:
This invention relates to that class of electric lamps in which two or more sets
of carbons are combined to operate successively in one lamp, and to afford a
continuous light, regardless of the consumption of the carbons, and without any
manual interference. The object of the invention is to so construct, combine and
connect the elements of a series of single lamps of the general character described
in the specification to letters patent granted to William Robert Lake dated the
5th December 1882 N° 5796 as to make a duplex or multiplex lamp which will
burn till the several sets of carbons are successively consumed and in particular to
accomplish this object by means of a compound automatic switch whose contact
points are the carbons of the lamp. The invention is not limited in its application
to any specific form of such single lamp, but is applicable to all electric lamps of
the general character of the said electric lamp, patented as aforesaid.-I shall
describe the present invention, in the form shown in the drawings, as applied to an
electric lamp and regulator thereof having a carbon-holder with a rod or tube
which slides through a friction clutch, or spring clamp, the latter being operated by
a magnet in a shunt circuit to produce feed, and by the recoil of a spring to separate
the carbons. The distinctive principle of this invention is conceived to consist in a
peculiar construction and use of the feed magnets of the improved lamp by the aid
of supplementary coils adapted to reinforce or neutralize, as the case may be the
electromagnetic action of the shunt coils of the said magnets, together with
appropriate connections so arranged that in a lamp of more members than one, the
electric current shall automatically control and operate the several members thereof
to produce the electric light between the members of each set; or pair of carbons in
succession. I proceed to point out the best mode in which my foreign correspondent
has contemplated applying the principle.
In the accompanying drawings
Figure 1 is an elevation partly in vertical section, of a duplex lamp, embodying

page_text: Figure 2 is an elevation, partly in vertical section, of a triplex lamp, or lamp of
three members, embodying this invention.
In Figure 1 A and B are two single electric arc lamps supported in a suitable
frame These lamps are each provided with an automatic feeding device z of the
kind above mentioned, and described in the specification to the said former letters
patent and the lamps are peculiar in their construction only as hereinafter
mentioned. The supporting springs embraced in the feed mechanism or devices,
before mentioned, are of equal stiffness and elasticity. A large wire P connected
with either pole of the generator say for example the positive pole, separates. at any
convenient point into two branches a and b The branch a proceeds to the magnet
in lamp B, is wound about the cylindrical core thereof, and constitutes the coarse
wire coil or helix a Then leaving the said magnet the same branch a passes at a²
directly to lamp A where by means of the binding post w and brush p it is
electrically connected with the carbon-rod a³ The branch wire b proceeds to the
magnet of lamp A is wound about the core thereof and constitutes the coarse wire
coil after being so wound about the said core, the branch wire b on leaving the
said magnet passes at 6 directly to lamp B where it is electrically connected,
through the binding-post w and the contact brush p' with the carbon-rods 6s.
Likewise a coarse wire N from the other pole of the generator, separates at any
convenient point into two branches a and b which are respectively connected with
the lower carbons a and b
Over the coil b¹ in lamp A in a direction to reinforce or assist the electro-magnetic
action of b¹ is wound the fine wire coil d' one end of which is connected, through
the connecting wire d and post w with the coarse wire a² and the other end of
which is electrically connected with N through the fine wire d And in like
manner, over the coil a' in lamp B in a direction to neutralize or counteract the
effect of a is wound the shunt coil e; one end of this coil is connected through the
fine wire c and the post w' with the large wire 62 and the other end of the same is:
connected with N through the fine wire c The coils b' and 'd' may be arranged in
any order, or may be wound side by side, or even on separate cores, without
departing from the essence of this invention, but I prefer to wind them in: the order
named beginning at the core of a single magnet as shewn; the coils aand c! may
also be arranged in any order, or side by side, or on separate cores without
departure from the spirit of this invention, but I prefer to arrange them about a
single cylindrical core in the order named and shown. The shunt coils d' and. c¹
which are of practically equal efficiency, are severally much stronger than the
coils a¹ and 6 severally, which also are of practically equal strength. The shunt
coils are strong enough when in.action, to overcome the resistance of the supporting
'or retractile springs in the feed mechanisms, before mentioned; while the coils a
and b' are not of sufficient power to accomplish that result. The feed mechanisms
of A and B are to be actuated by the said magnets, wound as above.
Such being the construction of this duplex lamp the mode of its operation is as
follows. When the current is not passing, through the lamp, the positive and
negative carbons of each set are 'held apart from each. other by the power of the
supporting springs embraced in the feed mechanisms of the respective members of
the lamp, and are not in contact; but as soon as the current from the generator is
passed through the lamp, the current from P Figure 1 follows the branch wires a
and b through the two members of the lamp in the following courses viz: that
portion of the said current which follows the branch wire a passes through the
helix a' the connecting wire.a' and the shunt d d and d to N and the generator;
that portion thereof which follows the branch wire b passes through the helix bi
the connecting wire 6' the shunt wires and coil c c¹ and c³ to N and the generator.
Such is the twofold course pursued by the electric current the instant the above
conditions are fulfilled. The effect of the passage of the electric current from P to N
in the courses described, through the shunt coils, is to draw down the spring-
armature of the feed mechanism in each member of the lamp; whereby the carbons
of each set are fed together to actual contact. The circuit is thereby closed through

page_text: both sets of carbons. In lamp A the circuit is closed through Pa a¹ a² a³ at a³ a
and N and in damp B through P b b¹ b² b³ b4 65 66 and N and as these courses offer
'less resistance to the passage of the current than de the courses before delineated,
through the said shunt coils, only a slight current now passes through d¹ and c¹.
The combined electromagnetic effect of the coils d' and ' is now equal to the
sum of their several electromagnetic effects; and the combined effect of the electro-
magnetic action of a and c is equal to the difference of their several effects; In
other words, the effect of the passage of the electric current through both lamps.
while the carbons are in contact is that in lamp A the electromagnetic action of di
is reinforced by that of b¹ while in lamp B the electromagnetic action of c¹ is
neutralized by that of a For the time being therefore, the magnet in lamp B
attracts its armature with less force than that with which the magnet of lainp A
attracts the armature belonging thereto. The armature in lamp B is no longer
attracted or drawn downward with sufficient force to resist and overcome the
energy of the spring in the feed mechanism therein; by the action of the said
spring and the spring-clamp in lamp B, the carbon rod 63 and the upper carbon b
are immediately drawn upward, whereby the carbons 6 and 65 are separated from.
each other, And the whole current from P to N except that which traverses the
shunts is caused to pass between the carbons a' and a The reason why the
voltaic arc does not appear between 6 and 6 when the latter are first separated in
the manner just described lies in the fact that the carbon current of lamp B is then.
short circuited through the carbons of lamp A. The breaking of the circuit at b* 68
as described, leaves the armature and feed mechanism of lamp A to be actuated by
the current through the shunt coil d'Hence lamp A now operates in the usual
manner, as a single lamp of the type specified; that is to say the current being
short circuited through the carbons a' and a³ a diminished current is sent through
the shunt coil d' so that the armature of the feed mechanism of this member, being
drawn downward by its magnet with less force than it is drawn upward by its
spring, is retracted by the latter, the rod a³ is raised, the carbons at and a³ are
separated, and the voltaic arc is produced between them, as shown in Figure 1. In
proportion as a and a are consumed and the distance between their points
increases, the strength of current through the shunt coil d' is increased and the
armature is drawn down, and with it its appurtenant spring-clamp, until the rod a³
is released, and the upper carbon a falls until the current through the shunt coil d¹ is
diminished by the shortening of the arc, the armature is released and the spring clamp
again holds the carbon rod a³ The separation of band 65 in the sequence here described
results necessarily from the counter action of the coils a¹ and c¹ before explained;
and after being separated as described, the carbons b' and 65 are kept apart by the
same means which brought them apart, so long as the counter action of the said
coils a¹ and c¹ continues; that is to say, until the current through a' is interrupted
by the separation and consumption of the carbons a' and a hereinafter explained.
This fixes the light in lamp A regardless of which set of carbons may have struck
first in coming together at first as above described; and prevents the light from
dodging back and forth between the sets of carbons. This is a prime feature of the
present invention; for the principal difficulty to be overcome when two or more
single lamps or sets of carbons are combined to form a duplex or multiplex lamp, is;
to cause one of such sets, and invariably the same set, to operate first, and to cause
another, and invariably the same other set, to operate next in order; and so on in a.
fixed and predetermined order, and to bring the carbons of each set together while
the others are held apart. Otherwise the light might appear in either member, and
pass from member to member indiscriminately. While the illumination in lamp A
continues the carbons in lamp B are held apart in the manner stated, and the upper
carbon a is fed down gradually as consumed, just as in the single lamp described in
the said former specification until the feed in lamp A is arrested by means of the
stop 3 on the carbon-rod a³ Then as the gradual consumption of the carbons in
lamp A continues, while feed no longer takes place, the voltaic arc between at and a³
lengthens, and an increasing current is passed through the said shunt coils by the way,

page_text: of the fine wires before mentioned. As the current through the shunt coils increases
the shunt coil c¹ overcomes and neutralizes the effect of the coarse wire coil a¹ and
causes the lamp B to feed until its carbons b' and 68 meet again in electrical
connection. Then the whole current which previously passed through the carbons a
and a at once passes through the carbons b and 65 the light in A goes out; at
the same time the armature and feed mechanism of lamp B are left to be actuated
by the current through the shunt coil c¹ while c¹ is at a minimum of efficiency by:
reason of the shortcircuit through the carbons 6 and 68, the armature, above is
therefore released and the carbon-rod 63 and carbon b' are lifted by the spring and
spring-clamp of the feed mechanism of this member, the carbons b and bare
thereby separated and the voltaic arc appears between them. Lamp B now
continues to act as a single lamp of the type before specified.
.
It will of course be understood that the electric current through c¹ and dis.
never fully interrupted while this duplex lamp is in operation. From the foregoing.
explanation it will also be understood that the differential magnet in lamp B
operates differentially while a current passes between at and a³ and practically at.
Do other time; and that the magnet in lamp A operates as a reinforced maguet
when a current passes from 6 to b³ and practically then only.
In order to apply to a lamp of three elements, or members, the principles of this
invention, which have already been shewn in their application to a duplex lamp,
it is necessary to increase, modify and connect the elements in the manner shewn
in the drawings Figure 2 and as hereinafter explained In Figure 2 A B and C
are the magnets which severally actuate the feed mechanisms of the three members
of such lamp respectively. Each of the said magnets is wound with a fine wire
or shunt coil and with two separate coarse wire coils. In magnet A the two
coarse wire coils b² and c¹ are wound and connected to act as supplementary_coils
adapted to reinforce the action of the shunt coil d¹ in the same. In magnet B the
coarse wire coil a¹ is a neutralizing or differential coil, and c³ is a supplementary
or assisting coil, as related to the shunt coil e¹ in the same magnet. In magnet C
the two coarse wire coils a³ and b³ are wound and connected to act as neutralizing
coils adapted to counteract the effect of the shunt coil f¹ in the same The three
coils of each magnet may be arranged in any order or position or even on separate
cores In each magnet the shunt coil is stronger than either of the remaining coils
of the same magnet and all the coarse wire coils in the lamp are of practically
equal strength. All the coils or helices represented in Figure 2 are of coarse wire
excepting the shunt coils de¹ and f¹ The three latter are of fine wire and are
connected as shunts about their respective carbons in the usual manner In the
triplex lamp a large wire P Figure 2 connected with one pole of the generator
divides at any convenient point into three branches ab and c; and a corresponding
large wire N from the other pole of the generator separates into 3 branches as b
and c which are in any convenient manner electrically connected with the three
lower carbons of the triplex lamp one branch. with each lower carbon The-
construction in other particulars and the remaining connections of this lamp will
be readily understood from the operation of the lamp as hereinafter explained from
an inspection of the drawings Fig: 2 and from the foregoing description of like
connections and the features of construction in the duplex lamp It will be
observed in view of the construction and connections mentioned that the carbon
current of each member of the triplex lamp is conducted about the magnet of each
preceding member of the same lamp as a supplementary coil adapted to reinforce
the shunt coil of each such preceding member whereby to produce feed and about
the magnet in each succeeding member of the same lamp as a differential coil to
neutralize the shunt coil of each such succeeding member to prevent feed therein.
In fig 2 the connection of the wire a and the Carbon rod as is indicated as
immediate instead of being represented as effected by contact brush or other
appropriate means And for convenience the connections b* 65 as well as cc are
represented in the same manner Such being the construction of the triplex lamp
the mode, of its operation is as follows When no current passes through the-

page_text: lamp the positive and negative Carbons of each set are separate being held apart
from each other by the spring clamp or other equivalent device belonging to the feed
mechanism but when a current is passed through the lamp the connections having.
been made as indicated the electric current from P Figure 2 passes in three
branches d e and f to the magnets A B and C respectively there it passes through
the shunt coils d'e' and f' severally and thence by the fine wires d' e² and f
passes to N and the generator The effect of the passage of such current from P to N
through the shunt coils as described is to draw down the armature in the feed*
mechanism in each member of the lamp whereby the Carbons in each member
are caused to approach each other until the Carbons of each set are in actual
contact The circuit P to N is then closed through each pair of Carbons' In the
first member it is so closed through P a a¹ as a³ a² a³ as a² a³ N In the second
member it is so closed through P b b¹ b² b³ b¹ bb bb76 N and in the third member
through Pccccccccc and N. Only a very slight current then passes through-
the shunt coils for the current is short circuited through the Carbons.-The effect
of the passage of the current from P to N in the triple course last described is that
in lamp A the electromagnetic action of dis reinforced by that of b¹ and c¹; in
magnet B the action of e' is reinforced by that of c³ and counteracted by that
of a', while in magnet C the effect of flis opposed by that of a³ and b³. The
combined effect of which actions and counter actions is that magnet A is more
strongly energized to cause feed in the manner before described than either of the
other magnets B and C while the magnet C is actuated least of all, and the
magnet B exerts an intermediate degree of force as a feeding magnet The
magnet C therefore no longer attracts or draws downward its armature with
sufficient power to overcome or resist the retractile energy of the spring which is
attached thereto The Carbon rod c and Carbon c are therefore drawn upward
and away from the Carbon c' by the action of the said spring and of the spring
clamp belonging thereto whereby the Carbons c6 and c7 being separated the current
through and between them is interrupted being short circuited through the branch.
wires a and b and the corresponding Carbons aª a7 and 6º 67 Thus the whole
current from P to N except the insignificant part thereof which traverses the
shunt coils is caused to pass between the Carbons a and a7 and the Carbons ¿ª.
and b The reason why the Voltaic arc does not appear between c and c
when they are first so separated lies in the fact that the current is then
shortcircuited through the remaining Carbons as just explained. The inter-
ruption in the manner stated of the current which proceeded by the course P
ccl c² c³ c¹ c c c c and N leaves the magnets A and B inoperative so far as respects
their respective coils c¹ and c³ so that magnet A is for the time being practically
reduced thereby to a magnet of two coils b¹ and d¹ and magnet B to a magnet
of two coils a¹ and e¹; A and B are thus for the time being constructed and-
connected in practically the sune way, are placed in practically the same
predicament, are caused to operate in the same way upon the same principles
and subject to the same explanation and are productive of the same effects in this.
triplex lamp as are the corresponding magnets of the members A and B of the
duplex lamp herein before explained, after the Carbons have been fed to contact in
the said duplex lamp. In short the magnets A and B then become for the time
being the magnets of a duplex lamp of the type above described and explained
embracing the two members of the triplex lamp which contain the said magnets
And when in the operation of such practically duplex lamp containing the
magnets A and B the Carbons a' and a have been first consumed and separated,
then the magnets B and C practically become in turn and for the time being the
magnets of a duplex lamp of the same type and operates in the same way as do
the said magnets of the duplex lamp to feed the Carbons to contact, to separate the
same successively and to produce the electric light next between 66 and 67 and
finally between c and c.-From the above it is obvious that in the improved lamp
the Carbons constitute or furnish the Contact points in a compound automatic

page_text: switch governing and co-ordinating the action of the several members of the lamp
in the manner described.
The principles of this Invention which have now been shewn in their application
to a duplex and to a triplex lamp may be applied to a multiplex lamp of any
greater number of members if that should becoine desirable by simple extension
and addition without the introduction of any new principle There is no need of
any switch magnet in any particular member of the improved lamp but it is
desirable to have a switch magnet or automatic cut-out in each such lamp.
considered collectively; which cut out may be of any ordinary construction and
arrangement In figure 2 such a cut-out is indicated at s between N and the
generator.
Having now particularly described and ascertained the nature of the said
Invention and in what manner the same is to be performed I declare that what
I claim is
First. An electric arc lamp containing two or more pairs or sets of Carbons
whose feed inechanisms are actuated by a series consisting of a corresponding
number of electromagnets; the first magnet in the said series being wound with a
shunt coil and with one or more supplementary coils and the last magnet in the
said series being wound with a shunt coil and with one or more differential coils in
which lamp each such set or pair of Carbons constitutes a pair of contacts in a
compound automatic switch regulating such lamp and coordinating the functions
thereof.
Second-In an electric arc lamp having two or more pairs or sets of Carbons.
whose feed mechanisms are actuated by a series consisting of a corresponding number
of magnets the first magnet in the said series being wound with a shunt coil and with
one or more coils supplementary thereto and the last magnet in the said series being..
wound with a shunt coil and with one or more differential coils, a compound
automatic switch whose contact points severally coincide with the points of said,
Carbons.
Third. The feed mechanism of an electric arc lamp in combination with an
electromagnet which is furnished with a spring armature or its equivalent and is
wound differentially and supplementarily with independent coils or helices for
operating the same: so that one or more of the said coils may be energized without
the others so that two or more of the said coils the same being wound in one and
the same direction may reinforce, or assist each other when traversed by the
electric current; and so that two or more of the said coils the same being wound
in different directions may neutralize or counteract each other when energized
whereby the action of the said feed mechanism may be governed and determined
by the number direction and electromagnetic energy of such of the said coils as are
for the time being brought into operation.
Fourth An electromagnet wound differentially and supplementarily with several
independant coils or helices for operating the same and furnished with a spring
armature or its equivalent in combination with a carbon rod or holder and.
intermediate feed mechanism of an electric arc lamp whereby the carbon which is
carried by such rod or holder may be raised lowered or held up according to the
number direction and electromagnetic energy of such of the said coils as are for the
time being brought into operation.
. Fifth-In an electric lamp a pair or set of Carbons, a Carbon rod or holder,
and a magnet wound with indepen·lant supplementary coils in combination with
intermediate feed mechanism whereby the said. Carbons may be made to approach
recede or stay apart according to the number and electromagnetic energy of the,
coils of such magnet which are for the time being traversed by the electric.
current.
Sixth In an electric lamp containing, two or more pairs or sets of Carbons a
series consisting of a corresponding nuinber of electromagnets the first magnet in.
the said series being wound with a shunt coil and one or more coils supplementary:
thereto and the last magnet in the said series being wound with a shunt coil and

page_text: with one or more coils differential thereto in combination with spring armatures
which are actuated similarly or dissimilarly thereby according to the course
pursued for the time being by an electric current in passing through the said
magnets.
Seventh In an electric arc lamp containing two or more pairs or sets of Carbons,
a series consisting of a corresponding number of supplementarily and differentially
wound electromagnets in combination with armatures of the said magnets actuated
thereby to produce similar or dissimilar motion or rest in the said armatures
according to the course pursued for the time being by an electric current energizing
the said magnets.
Eighth In an electric lamp containing two or more pairs or sets of Carbons a
corresponding number of interconnected electromagnets wound with independent
coils in combination with feed mechanisms actuated thereby; whereby the action
of such feed mechanisms is governed and determined by the course pursued by an
electric current energizing the said magnets.
Ninth In an electric arc lamp containing two or more pairs or sets of carbons:
a series consisting of a corresponding number of electromagnets the first magnet
in the said series being wound with a shunt coil and with one or more coils
supplementary thereto and the last magnet in the said series being wound with a
shunt coil and with one or more coils differential thereto in combination with a
corresponding number of Carbon supporting rods and intermediate feed mechanisms
actuated by the said magnets whereby the said Carbon supporting rods may be
independently raised lowered or held in position according to the number direction
and strength of the currents energizing the said magnets.
Tenth In an electric lamp two or more pairs or sets of Carbons and a
corresponding number of differential and supplementary magnets in combination
with intermediate mechanisms actuated by the said magnets to impart to the said
sets of Carbons independent separating and feeding movements, whereby, the
electric light may be established between the members of one of the said pairs or
sets at a time while the members of the remaining pair or pairs are held apart.
Dated this 21st day of October 1884.