Improvements in the Construction of Electric Arc Lamps and Appliances used therefor.
Year: 1891

page_text: Date of Application, 13th Jan., 1891
Complete Specification Left, 14th Aug., 1891-Accepted, 7th Nov., 1891
PROVISIONAL SPECIFICATION.
Improvements in the Construction of Electric Arc Lamps and
Appliances used therefor.
I, HERBERT JOHN ALLISON, of 52 Chancery Lane, London, in the County of
Middlesex, Patent Agent, do hereby declare the nature of this invention (which
has been communicated to me from abroad by Barton Brewer Ward, of the
City, County and State of New York, United States of America, Electrician) to
be as follows:-
My invention relates to improvements in the construction of electric arc lamps
and appliances used therefor, and consists, First, in an improved magnet system by
which the carbons of the lamp are separated to form the arc and are regulated in
their feed.
Second; My invention relates to the manner of disposing and mounting the
artificial electric resistance used in connection with electric arc lamps.
Third The invention consists in improvements in the automatic safety
appliances employed for protecting the lamp from injury in case the resistance of
the circuit through the carbons should become abnormally high or the arc should
be ruptured.
The object of the first part of my invention is to improve the action of electric
arc lamps run on constant potential circuits, by providing a system of main and
derived circuit regulating magnets which shall be steady and regular in action and
at the same time have the requisite power and delicacy in operation.
It is well known that in arc lamps run on constant potential circuits, the changes
in resistance of the arc will produce great and abrupt changes in the flow of
current in the main circuit coil of the magnet system and there is a great tendency
to irregularity of operation and to what is known as a pumping action produced by
the extreme or wide fluctuations in the movements of the parts of the magnet
system which connect to the lever that sustains the positive carbon.
The invention consists in a magnet system comprising main and derived circuit
magnets wound and connected as usual in the art but each having a movable core
carried by the lever which supports the carbon and feed regulating mechanism and
each pulling in opposition to the other, in combination with a mass of iron forming
a magnetic connection between the poles of the cores which are within the magnet
coils, and arranged in proper proximity to said coils or cores so that they may both
act upon it to change its magnetic condition or cause a change of magnetic
induction from one end to the other thereof.
When the cores and the magnetic mass of iron extending from one pole to the
other are properly organized and adjusted and when the current decreases in one of
the coils and the core thereof is thereby permitted to move in a direction to carry it
out of the coil, the core of the other magnet will be brought into closer magnetic
relation to the iron connecting piece, and through its induction upon the same will
cause an increase of the magnetic reaction between the opposite end of said con-
necting piece and the pole of the core which is moving in a direction to carry it
out of its coil. Thus, for instance, when the main circuit coil decreases in strength
and the derived circuit coil either being of the same strength or increasing, pulls
its core down into closer magnetic relation to the magnetic connecting bar, the
induction of said core upon the bar is increased and the reaction between the con-
necting bar and the end of the core of the main circuit coil increases so that there
will be a compensation for the movement which takes the core out of its coil and

page_text: for the large decrease in the power of said main circuit magnet which occurs in
lamps on constant potential circuits thereby conducing to steadiness of action.
On the other hand when the main circuit magnet draws its core down into its
coil and the derived circuit magnet core tends to move away from the connecting
bar into a less effective position, the reaction between the connecting bar and the
said latter core is increased owing to the fact that the main circuit core is brought
into closer magnetic relation with the same. There is, therefore, an increase in the
magnetic attraction between the derived circuit core and the magnetic bar which
tends to compensate for the sudden or great change of magnetic condition in the
main circuit magnet that would otherwise give rise to unsteadiness of action in the
lamp.
In constructing a lamp in which such a magnet system is used, I make the frame
of the lamp of iron and arrange the poles of the cores of the main and derived
circuit magnets so as to be in proximity to parts of said frame whereby the frame
may act as the magnetic connection just described.
The second part of my invention relates to a means for protecting the lamp
from injury when the circuit through the arc is interrupted, and consists essentially
in interposing a switch into a circuit of the derived circuit field regulating magnet
for opening and holding open the circuit of such coil and in controlling or bringing
such switch or circuit opener into operation through the action of a controlling
magnet or other device which is adapted to respond to any abnormal increase in
the resistance of the circuit through the arc. This part of my invention is applic-
able to arc lamps in which no main circuit magnet may be employed but the
operation shall be produced entirely by a derived circuit magnet.
The circuit opening switch in the circuit of the derived circuit magnet is prefer-
ably controlled by an electro-magnet which is in the circuit of the current flowing
to the arc but might be in the circuit of the current flowing in a derived circuit
around the arc or is acted upon by a combination of such currents.
In the first case the armature levers of the magnet would serve when attracted to
hold the circuit of the derived circuit magnet closed by making contact with a suit-
able stop and when the magnet loses its power the armature would drop back and
break such derived circuit. In case the switch or circuit opener is subjected to the
action of a derived circuit magnet alone, then the contact of the switch would
be so arranged that the armature, when it is attracted by such derived circuit
magnet, would open the circuit to protect the derived circuit regulating
magnet of the lamp. The switch may be held in position to keep the said derived
circuit open by means of an electro magnet or coil whose circuit shall be closed by
a contact which is operated by the switch lever when it is moved in a direction to
break the derived circuit containing the feed regulating magnet.
Instead of an
electro magnet any other device, known to electricians, which shall respond directly
or indirectly to variations in electric current may be used for the purpose of the
invention.
My invention further consists in the provision of means whereby the current may
be shunted around the lamp at the same time that the coils of the feed regulating
derived circuit magnet are cut out of circuit. The shunt circuit around the lamp,
preferably contains a resistance.
The third part of my invention relates to the manner of disposing the artificial
resistance used in connection with the automatic switch forming the subject of the
second part of my invention or any other resistance used in connection with an
electric arc lamp either in circuit with the carbons or in a shunt around them.
The object is to secure compactness, accessibility and facility of handling, as well
as to permit the electric resistance to be readily connected up to the lamp circuits
in any way, as in series with the carbon or into the branch circuit of the cut out
device.
The invention consists in mounting the electrical resistance wire on a frame
which is suspended or supported within the chimney for the hood of an electric arc
lamp and independently of the lamp, and providing such lamp with a vertical

page_text: passage or opening through which the lamp chimney or horn of the lamp may pass
vertically so as to permit the lamp to be removed from the hood or supported
therein at pleasure without interfering with the electrical resistance which is
supported by the hood entirely.
The invention consists further in providing the electrical resistance frame with
suitable binding posts forming the terminals of the electric resistance and in pro-
viding the hood with binding posts adapted for connection with the two line wires
and with supplemental connecting posts or screws for permitting the connections of
the resistance with the lamp and line wires to be changed at pleasure so that the
resistance may be included either in circuit with the electric arc or may be con-
nected to a binding post of the lamp which is in turn connected to an automatic
electric switch that shall close a branch circuit including such resistance when the
are becomes too long or is interrupted. Hence the lamp may be used either as an
ordinary series are lamp or by including the resistance in circuit with the carbons
may be used on constant potential circuits or the potential ordinarily employed for
incandescent lamps.
The resistance frame itself consists of two heads preferably of insulating material
connected by a tube in any desired manner, said tube forming a passage for the
horn of the arc lamp. The heads are provided with slots adapted to receive a
number of bars or rods of insulating material which are mounted one upon the
other within the slots and are preferably provided with notches or grooves to
receive the resistance wire and may have rabbets or offsets at their ends which
will engage with the heads to prevent said bars from becoming displaced or
dropping out of the radial notches or slots. The resistance wire is wound upon
these bars or rods and held in place between them. In constructing the resistance
a layer of wire is wound over the set of bars placed in the slots which may be of
any number and then a second set of bars is placed over said layer and the second
layer of resistance wound upon the latter set.
The resistance frame may be secured in the lamp hood by means of extensions
from the lower head fastened to the underside of the top plate of the lamp. Binding
posts to which the terminals of the resistance wire are connected are mounted on
the lower head in position to be readily accessible.
Dated this 13th day of January 1891.
ALLISON BROS.,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Construction of Electric Arc Lamps and
Appliances used therefor.
I, HERBERT JOHN ALLISON, of 52 Chancery Lane, London, in the County of
Middlesex, Patent Agent, do hereby declare the nature of this invention (which
has been communicated to me from abroad by Barton Brewer Ward, of the
City, County and State of New York, United States of America, Electrician),
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 improvements in the construction of electric arc lamps
and appliances used therefor, and consists, First, in an improved magnet system by
which the carbons of the lamp are separated to form the arc and are regulated in
their feed.
Second; my invention relates to the manner of disposing and mounting the
artificial electric resistance used in connection with electric arc lamps.
Third; the invention consists in improvements in the automatic safety appliances
employed for protecting the lamp from injury in case the resistance of the circuit
through the carbons should become abnormally high or the arc should be
ruptured,

page_text: The object of the first part of my invention is to improve the action of electric
arc lamps run on constant potential circuits, by providing a system of main and
derived circuit regulating magnets which shall be steady and regular in action and
at the same time have the requisite power and delicacy in operation.
It is well known that in arc lamps run on constant potential circuits, the changes
in resistance of the are will produce great and abrupt changes in the flow of
current in the main circuit coil of the magnet system and there is a great tendency
to irregularity of operation and to what is known as a pumping action produced by
the extreme or wide fluctuations in the movements of the parts of the magnet
system which connect to the lever that sustains the positive carbon.
The invention consists in a magnet system comprising main and derived circuit
magnets wound and connected as usual in the art but each having a movable core
carried by the lever which supports the carbon and feed regulating mechanism and
each pulling in opposition to the other, in combination with a mass of iron forming
a magnetic connection between the poles of the ccres which are within the magnet
coils, and arranged in proper proximity to said coils or cores so that they may both act
upon it to change its magnetic condition or cause a change of magnetic induction
from one end to the other thereof.
When the cores and the magnetic mass of iron extending from one pole to the
other are properly organized and adjusted and when the current decreases in one of
the coils and the core thereof is thereby permitted to move in a direction to carry
it out of the coil, the core of the other magnet will be brought into closer magnetic
relation to the iron connecting piece, and through its induction upon the same will
cause an increase of the magnetic reaction between the opposite end of said con-
necting piece and the pole of the core which is moving in a direction to carry it
out of its coil. Thus, for instance, when the main circuit coil decreases in strength
and the derived circuit coil either being of the same strength or increasing, pulls
its core down into closer magnetic relation to the magnetic connecting bar, the
induction of said core upon the bar is increased and the reaction between the con-
necting bar and the end of the core of the main circuit coil increases so that there
will be a compensation for the movement which takes the core out of its coil and
for the large decrease in the power of said main circuit magnet which occurs
in lamps on constant potential circuits thereby conducing to steadiness of action.
On the other hand, when the main circuit magnet draws its core down into its
coil and the derived circuit magnet core tends to move away from the connecting
bar into a less effective position, the reaction between the connecting bar and the
said latter core is increased owing to the fact that the main circuit core is brought
into closer magnetic relation with the same. There is, therefore, an increase in the
magnetic attraction between the derived circuit core and the magnetic bar which
tends to compensate for the sudden or great change of magnetic condition in the
main circuit magnet that would otherwise give rise to unsteadiness of action in
the lamp.
In constructing a lamp in which such a magnet system is used, I make the frame
of the lamp of iron and arrange the poles of the cores of the main and derived
circuit magnets so as to be in proximity to parts of said frame whereby the frame
may act as the magnetic connection just described.
The second part of my invention relates to a means for protecting the lamp
from injury when the circuit through the arc is interrupted, and consists essentially
in interposing a switch into a circuit of the derived circuit field regulating magnet
for opening and holding open the circuit of such coil and in controlling or bringing
such switch or circuit opener into operation through the action of a controlling
magnet or other device which is adapted to respond to any abnormal increase in
the resistance of the circuit through the arc. This part of my invention is
applicable to arc lamps in which no main circuit magnet may be employed but the
operation shall be produced entirely by a derived circuit magnet.
The circuit opening switch in the circuit of the derived circuit magnet, is
preferably controlled by an electro-magnet which is in the circuit of the current

page_text: flowing to the arc but might be in the circuit of the current flowing in a derived
circuit around the arc or is acted upon by a combination of such currents.
In the first case the armature levers of the magnet would serve when attracted
to hold the circuit of the derived circuit magnet closed by making contact with a
suitable stop and when the magnet loses its power the armature would drop back
and break such derived circuit. In case the switch or circuit opener is subjected
to the action of a derived circuit magnet alone, then the contacts of the switch
would be so arranged that the armature, when it is attracted by such derived circuit
magnet, would open the circuit to protect the derived circuit regulating magnet of
the lamp. The switch may be held in position to keep the said derived circuit open by
means of an electro-magnet or coil whose circuit shall be closed by a contact which is
operated by the switch lever when it is moved in a direction to break the derived
circuit containing the feed regulating magnet. Instead of an electro-magnet any
other device, known to electricians, which shall respond directly or indirectly to
variations in electric current may be used for the purpose of the invention.
My invention further consists in the provision of means whereby the current
may be shunted around the lamp at the same time that the coils of the feed
regulating derived circuit magnet are cut out of circuit. The shunt circuit around
the lamp, preferably, contains a resistance.
The third part of my invention relates to the manner of disposing the artificial
resistance used in connection with the automatic switch forming the subject of the
second part of my invention or any other resistance used in connection with an
electric arc lamp either in circuit with the carbons or in a shunt around them.
The object is to secure compactness, accessibility and facility of handling, as
well as to permit the electric resistance to be readily connected up to the lamp
circuits in any way, as in series with the carbon or into the branch circuit of the
cut-out device.
The invention consists in mounting the electrical resistance wire on a frame
which is suspended or supported within the chimney for the hood of an electric
arc lamp and independently of the lamp, and providing such lamp with a vertical
passage or opening through which the lamp chimney or horn of the lamp may pass
vertically so as to permit the lamp to be removed from the hood or supported therein
at pleasure without interfering with the electrical resistance which is supported by
the hood entirely.
The invention consists further in providing the electrical resistance frame with
suitable binding posts forming the terminals of the electric resistance and in
providing the hood with binding posts adapted for connection with the two line
wires and with supplemental connecting posts or screws for permitting the con-
nections of the resistance with the lamp and line wires to be changed at pleasure so
that the resistance may be included either in circuit with the electric arc or may
be connected to a binding post of the lamp which is in turn connected to an
automatic electric switch that shall close a branch circuit including such resistance
when the arc becomes too long or is interrupted. Hence the lamp may be used
either as an ordinary series arc lamp or by including the resistance in circuit with
the carbons may be used on constant potential circuits or the potential ordinarily
employed for incandescent lamps.
The resistance frame itself consists of two heads preferably of insulating
material connected by a tube in any desired manner, said tube forming a passage
for the horn of the arc lamp. The heads are provided with slots adapted to receive
a number of bars or rods of insulating material which are mounted one upon the
other within the slots and are preferably provided with notches or grooves to
receive the resistance wire and may have rabbets or offsets at their ends which
will engage with the heads to prevent said bars from becoming displaced or
dropping out of the radial notches or slots. The resistance wire is wound upon
these rods or bars and held in place between them. In constructing the resistance
a layer of wire is wound over the set of bars placed in the slots which may be of

page_text: any number and then a second set of bars is placed over said layer and the second
layer of resistance wound upon the latter set.
The resistance frame may be secured in the lamp hood by means of extensions
from the lower head fastened to the underside of the top plate of the lamp.
Binding posts to which the terminals of the resistance wire are connected are
mounted on the lower head in position to be readily accessible.
In the accompanying drawings
Fig. 1, is a side elevation of an electric arc lamp having its magnet system con-
structed in accordance with the invention. The figure shows also the switch
magnet for protecting the derived circuit magnet of the system.
Fig. 2, is a diagram illustrating the circuits of the lamp with the safety switch
applied.
Figs. 3 and 4, are diagrams illustrating modifications in the arrangements of
circuits and magnets for controlling the action of the safety switch.
Fig. 5, is a side elevation and partial section of the lamp hood illustrating the
manner of supporting the resistance frame therein and the way in which the lamp,
when suspended in the hood, has its horn or chimney projecting up into said
resistance frame.
Fig. 6, illustrates one of the ways in which the resistance may be connected
into the circuit of the lamp.
Fig. 7, is a plan of the resistance and frame.
Fig. 8, is a side elevation and vertical cross section through a part of the same.
Fig. 9, is a side elevation of a preferred form of bar of insulating material which
is supported in the frame and upon which the resistance wire is wound.
A, indicates the carbon holder or carrier which is engaged by the feed regulating
mechanism and is supported thereby while the arc is burning in any proper manner.
The mechanism herein illustrated is an ordinary gear mechanism which gears with
a rack on the carbon carrier and the whole or a portion of which gear mechanism
is supported upon the regulator lever of the lamp, indicated at R.
is
At X, is indicated the usual escapement for the gear mechanism and at W,
indicated a stop which prevents the vibration of the escapement when lifted against
the stop and thereby holds the carbon from feeding. When the escapement is
lowered from contact with the stop W, then the carbon is free to feed down.
Regulator lever R, is pivoted in a suitable frame at 3, and carries at its opposite
ends the cores G, F, of the main and derived circuit magnets. The derived circuit
magnet core F, is hung from the long arm of said lever so that it may have a
mechanical advantage over the main circuit magnet and so that further a com-
paratively limited movement of such derived circuit magnet core as compared with
that of the main circuit magnet core may result in producing a feed of the carbon.
The coils for the main and derived circuit magnets indicated at I, K, respectively,
and within which the cores move as indicated, are mounted directly upon a base
plate L, which is connected with or forms a part of the surrounding exterior frame
or case on or within which the parts of the lamp are mounted and supported. This
frame is constructed of iron. I also preferably construct the depending arms N, for
the lower carbon, of iron and attach them to, or form them in one piece with, the
base L. The core G, of the main circuit magnet, as shown, has its lower end in
rather close proximity to the iron frame or mass of iron upon which its coils I, are
mounted so that when the magnet is excited the core will be drawn down by the
attraction between its lower end and the iron mass presented to it. The derived
circuit magnet coils K, being mounted in similar manner upon the iron frame, the
core F, moving in such coils will be subjected to similar attractive influence as well
as to the pulling action of the coils which tend to pull the cores down within
the coils.
In order to give a smoother and more gradual pulling action between the ends of
the cores and the iron mass to which they are presented, the ends of the cores may
be rounded or bevelled, as indicated. The same effect might obviously be obtained

page_text: by providing the attracting iron mass with a conoidal or pointed projection
presenting itself to the end of the core.
The main and derived circuit coils K, I, may be wound in any desired manner
either in a way to cause both lower ends of the cores F, G, to be of the same
polarity or to be of opposite polarity.
D, is a switch that is placed in the circuit of the derived circuit magnet or coil and
serves to open and close the circuit of the same. In the form shown in Fig. 1, the
switch is pivoted on a post that by a suitable wire is connected to one pole of the
circuit while the contact stop 5, therefor, connects to one end of coil K, the other
end of said coil connecting to the other pole of the circuit. The connection might
instead be made and broken by contact of the lever D, or the armature carried
thereby with the core of the magnet E, which operates in it. Such connections
are indicated in the diagram Fig. 2, which also shows the connections of the
coils I, K.
E, indicates an electro magnet, or other electro responsive device, which is in the
circuit leading through the carbons and which has an armature carried by the
switch lever D. When the magnet E, is excited by the current flowing through
the carbons, in the usual manner, or to the usual extent, the magnet E, is of
sufficient power to hold the circuit opening switch D, raised against the stress of
spring S, and in position where it will close the circuit of the magnet K.
Should the resistance in the circuit through the arc become abnormally high or
should the arc break, the magnet E, will decrease in power to a sufficient extent to
allow the retractor S, to open the switch thereby breaking the circuit of the
magnet K. This device is designed especially for use on constant potential circuits
where are lamps are fed in multiple between two mains a, b, as indicated. The
effect of the device is to remove the derived circuit magnet from connection with
such mains and to prevent abnormal heating thereof in case the circuit through the
arc should become broken for any reason. The switch D, or other device responsive
to such abnormal increase of current might also operate to close a shunt circuit
around the lamp containing a resistance which is the equivalent of the lamp
resistance or which is a shunt of low resistance. Such shunt or branch circuit is to
be used in those cases where two or more lamps are run in series.
Fig. 3, shows an arrangement of this description wherein the circuit opening
switch is provided with contacts that close the safety branch and is controlled by
the joint action of current in a derived circuit around the are and in the main
circuit, the effect, however, being as before, to bring such circuit opening switch
into operation on the occurrence of an abnormal increase in the arc circuit, in the
well understood manner.
When the magnet E, is wound with two coils one of which, indicated by the
numeral 1, is in the circuit with the main circuit coil I, while the other, indicated
by the numeral 2, is included in the derived circuit around the arc and, in this
instance, is shown in series with the coils of K. The two coils 1, 2, are wound so
as to oppose one another, but the coil 1, is made to be superior to the coil 2,
when the arc is burning or when the resistance in the arc circuit is of normal
amount.
One terminal of 2, connects to the core of the magnet while the other terminal
connects to the coil K. Under these conditions the magnet E, holds up the
armature lever consisting of the switch L, and thereby presses a supplemental spring
contact D, against the core of the magnet thus completing the circuit from the
terminal of coil 2, through the switch D, to the main line L, by way of an artificial
resistance R'. The resistance R', has no special function under this condition of
the parts and is only of benefit as constituting a resistance in the safety branch
around the lamp formed when the lever D, drops against a back contact stop H,
which is connected to the opposite pole of the lamp as shown.
When the lamp is burning, the switch lever D, is held up but should the arc get
abnormally high, the power of coil 1, decreases while the power of coil 2, opposing 1,
increases until finally the magnet becomes so weak that the retractor S, may operate

page_text: the circuit opening switch D, thereby breaking the circuit of the derived circuit
magnet K. This action is accompanied by the closure of a safety branch or shunt
in obvious manner.
The derived circuit magnet K, of the regulator system being thus entirely
removed from circuit, and remaining so removed, cannot by any possibility become
heated even though the lamp should remain out of operation for a long time while
connected to a line circuit.
In Fig. 4, I have shown an equivalent way of controlling the circuit opening
switch through a change of resistance in the arc circuit. Here the circuit opening
switch is held in position to keep the circuit open through the magnet K, by means
of a supplemental magnet coil 4, that is put into circuit by the movement of the
switch lever to open the circuit of the magnet K. The switch D, is here actuated
by means of a derived circuit magnet in a branch of high resistance around the arc.
The power of this magnet is ordinarily insufficient to operate the circuit opening
switch so that the latter may remain in position to keep the circuit through the
magnet K, closed. Here the normal circuit is through the back contact of the
lever D. If the are lengthens abnormally or breaks, or the resistance for any other
reason becomes abnormally high in the arc branch, the circuit opening switch D,
will be lifted and will open the circuit for the derived circuit magnet K, and will
retain its circuit opening position through the action of the magnet coil in the
circuit closed against a front contact M, in the well known manner.
It will be understood that in all cases, before described, where the switch is held
closed by a main circuit coil, such coil should be of sufficient power at starting the
lamp to operate the switch when the current is first turned on and passes through
the carbons so as to complete the circuit for the derived circuit feed regulating
magnet. In the case illustrated in Fig. 4, the switch will assume the proper
position when the current is turned off of the circuit and when the current is turned
on it will find the switch in position where the circuit of the derived circuit feed
regulating magnet is closed which position it will retain until the conditions before
described may exist.
The supplemental spring D², through which the circuit is closed in Fig. 3, serves
simply to preserve the circuit for an instant after the lever D, begins to move away
from the magnet so that when finally in its downward movement it opens the
derived circuit the momentary increase of power in the magnet E, in the arc
circuit, cannot again attract the armature and raise the switch."
A', Fig. 5, indicates the lamp hood of any ordinary shape adapted to protect an
out-door electric arc lamp, and having the usual chimney B.
C', indicates in outline the case of an electric arc lamp, and D, D', hooks which
may also form electric terminals of the lamp and are adapted to suspend the lamp
from hangers E², E'. These hangers may be in electrical connection with binding
posts or blocks F, F, supported by the head of the hood but insulated therefrom
as indicated. They may be held in place by means of bolts H2, which pass up
through the heads and are provided with nuts G', that may have eyes or hooks for
suspending the hood. The bolts H, have bushings of insulating material as
indicated. The blocks or posts F3, F³, of conducting material are properly con-
nected with the line wires W2, W Block F³, may have one wire fastened
directly to it while the other block F, may be connected by a short circuit
wire W, the terminals of which are fastened respectively to block F', and to a
third block or post F, sustained in the head of the hood and having the other line
wire connected directly to it.
R, is the artificial clectric resistance mounted on a suitable frame and sustained
within the chimney of the hood as indicated. This resistance frame or support is
provided with a vertical central passage adapted to receive the chimney K³, of the
lamp when the lamp is sustained within the hood in the ordinary or any suitable
manner.
The chimney B, is provided at or near its top with a number of openings as
shown through which the air heated by contact with the résistance coils may

page_text: escape. It will be seen that by this arrangement, a circulation of cooling currents
of air is provided for up through the chimney and out of the top thereof, such
current coming into contact with the resistance wires and thereby keeping their
temperature down should it tend to become excessive.
The terminals of the electric resistance wire are connected to binding posts I, I³,
sustained on the resistance frame or some part independent of the lamp. In the
arrangement of the apparatus shown one of such posts I2, connects to the block F³,
while the other is connected by a flexible wire with a post on the lamp which
connects with the cut-out circuit in the lamp. By this arrangement the
resistance R, will be in the cut-out circuit when the cut-out magnet E, lets its
armature drop to make connection with the stop that is connected to the hook D*,
and hanger E, sustained from the post or block F2. The armature lever for E,
being connected with the post that is joined to post I³, the cut-out circuit will be
formed in obvious manner.
The construction of the resistance frame whereby a suitable ventilation is
provided and whereby the central passage is readily provided for the chimney K³,
is shown more clearly in Figs. 7, 8 and 9. The supporting frame or carrier on
which the resistance wire R2, is wound is made as follows:-
L', L' are heads of a supporting frame connected by a central tube L, joined
to the heads in any proper manner. In the heads L, L³, are radial slots or
openings adapted to receive bars M', which may be of any suitable width or
thickness in a radial direction and which are superposed upon one another in the
slots as indicated. These bars or blocks are of insulating material such as
porcelain, lava, asbestos, or other suitable material and are provided at their outer
edges with notches or guides adapted to receive the resistance wire. The inner
one of the bars in each slot is provided as shown in Fig. 8, with rabbets adapted
to engage with rabbets or shoulders formed on the heads so that it cannot slip out
of place endwise. In building up the resistance the several bars or rods nearest the
centre of the heads are put in place and wire is wound around and over the same
in the grooves until the grooves are filled after which another set of bars is put in
place over the first and the winding continued, the operation being repeated a
number of times corresponding to the number of bars employed, the thickness of
the wire and the distance desired between the several layers. It is best to have
the heads cut away as much as possible leaving, however, sufficient material in
which the slots may be formed, since by this means the wire will be better exposed
to ventilating currents of air which may circulate upward freely through the same
in the spaces between the arms or extensions in which the slots are formed. On
the lower head, the binding posts I³, I³, are mounted and properly insulated there-.
from as indicated.
To support the resistance frame I may provide the lower head with arms or
extensions as indicated in Fig. 7, in which bayonet joint slots are formed adapted
to engage with the pins i, on the head of the hood. The hood and resistance
frame with resistance wire in place are fastened together as shown in Fig. 5, and
connection with them is made when the lamp is put in place. Should it be desired
to use the resistance as a shunt or branch resistance around the lamp controlled by
a cut-out switch, the connections may be made as in Fig. 5. If, however, it is
desired to place the resistance in circuit with the carbons of the lamp, as may be
sometimes necessary, then the connections may be readily changed as indicated in
Fig. 6. In this case the connecting wire between post F, and post F, is detached
so as to break connection from F', to F'. Post I, and post or block F, are also
disconnected, and a wire is run from F, directly to I'. Another connection is run
directly from post I³, of the resistance to the block F2, thus putting the resistance
in the circuit with the carbons, as indicated in Fig. 6.
It will be obvious that by means of these connecting devices, or similar con-
necting devices adapted to change the connections between the resistance, the lamp
and the line blocks or binding posts, that the resistance might be put into circuit
in other ways.
When the lamp is removed the resistance remains in place.

page_text: Having thus particularly described and ascertained the nature of my said inven-
tion and the manner in which the same is to be performed, I declare that what I
claim is :-
1. In an electric arc lamp, the combination with the main and derived circuit
coils, of movable cores for both coils supported by a feed regulating lever of the
lamp and having their ends both presented in magnetic relation to an iron plate or
mass, formed by the iron frame of the lamp or otherwise, which extends from one
coil to the other and into close proximity with the ends of said cores, as and for
the purpose described.
2. The combination in an electric arc lamp, of a derived circuit feed regulating
magnet, a circuit opening switch which normally or while the arc is of normal
length, maintains the connection of such derived circuit magnet coil with the main
or supply circuit closed, but which is adapted on operation to hold such connection
open, and a device such as an electro-magnet responsive to abnormal resistance in
the circuit of the arc for bringing said switch into operation, as and for the purpose
described.
3. The combination in an electric arc lamp, of a switch D, normally completing
the circuit through the feed regulating derived circuit magnet for the lamp, a
magnet coil in the circuit of the are adapted whea excited to hold such switch in
circuit closing position, and a retractor operating on such switch for opening the
circuit of the feed regulating magnet when the current through the arc decreases
to an abnormal extent.
4. The combination in an electric arc lamp, of a switch having back and front
contacts, the front one of which is included in the circuit of the derived circuit
feed regulating magnet, while the back contact is in a shunt or branch circuit
around the lamp, and a controller magnet for such switch having a coil in a
circuit through the arc, as and for the purpose described.
5. The combination with an electric arc lamp, of a lamp hood, a chimney for
the arc lamp, and an artificial resistance frame mounted in the chimney of the hood
independently of the lamp and provided with a vertical passage or opening to
receive the lamp chimney.
6. The combination with an electric arc lamp, a hood therefor, a chimney for the
arc lamp, binding posts for connection with the line wire mounted in the head of
the hood for such lamp, an electric resistance frame secured within the chimney of
the hood and having a vertical central passage or opening for the chimney of the
lamp, and binding posts or connecting devices, substantially as described, for
permitting the connections of the resistance with the lamp and line wires to be
changed at pleasure.
7. In an electric resistance frame, the combination with the supporting frame
having the heads provided with radial slots, of insulating bars or rods scated in the
slots and superposed upon one another, and resistance wire wound over said bars in
layers between them.
8. The combination with the resistance frame having the connected heads and a
central passage or bore, of a wire supporting bar or rod provided with notches in
its outer edge and with rabbets or shoulders at its inner edge to hold it against
longitudinal displacement.
Dated this 14th day of August 1891.
ALLISON BROS.,
Agents for the Applicant.