Improvements in Regulators for Electric Arc-lights.
Year: 1886

page_text: Date of Application, 12th Aug., 1888.
Complete Left, 14th Dec., 1886.
Complete Accepted, 22nd Apr, 1887.
Improvements in Regulators for Electric Arc-lights.
I, ALFRED JULIUS BOULT of 323 High Holborn, in the County of Middlesex,
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention relates to improvements in regulators for electric are lights and it
consists essentially in combining the arc-light with certain resistances in such a
manner that systems of electromagnets and solenoids without mechanisın can be used
for the direct regulation of the arc-light, such systems having neither a constant
attraction nor a synetrical attraction curve, conditions which are essential and
necessary to the regulators hitherto in use.
The regulation of this regulator is perfectly independent of the attraction and only
requires a system of electromagnets and solenoids in which, by reversing the current
in one part thereof, the direction of the movement is also reversed.
The following will explain the above assertions.
Suppose an electromagnet is provided with elongated poles and on these poles two
solenoids are moving free, connected with each other by a cord running over pulleys.
If a current is sent through these solenoids in such direction that one at the top has
the same pole as the electromagnet but the other has the opposite then there will be
a movement of the solenoids repelling the same poles and attracting the opposite of
solenoid and electromagnet.
The force which moves the solenoids is different in different positions of the latter
and this difference has its cause in the fact that the forces of the solenoids are summed
together in certain positions, but partly compensate each other in others.
If the direction of the current in the solenoids is reversed, while it remains the same
in the electromagnet, then the direction of the movement is also reversed.
From this, it is easy to see, that it is possible to combine such systems of electro-
magnets and solenoids in which in large circuits, by reversing the current in a part of
the system, the direction of the movement is also reversed.
The following is to explain that with a correct reversion of the current such system
TD 077

page_text: can be used for the regulating of arc-lights and that such reversion of the current can
be produced automatically without intricate mechanism and without interrupting the
current, by a combination of the arc with proper resistances; and this is the principal
point of the present invention.
Firstly. It is to be shewn, how the system can be employed for the regulating of
the arc light. Supposing the two solenoids carry carbonholders with carbons touching
each other and the current is sent through the lamp, the solenoids must have such poles
towards the electro-magnet that a movement in such a direction results, that the
carbons are separated and the arc produced. In the moment when the normal are is
reached the current in the solenoids ceases, through the forces compensating each
other, and the movement stops. If the system is properly adjusted the carbons will
remain in this position until they burn away and the are becomes too long, in which
case the current is to flow through the solenoids in the reverse direction, resulting in
a reverse movement so that the carbons are moved towards each other until the normal
are is reached again, when the current ceases in the solenoids and the movement
stops again.
For the proper operation of the lamp there are therefor three problems to solve i.e.
with the normal length of the arc, the current in solenoids is to be nil, then with a short
arc the current must flow through the solenoids in one direction, and with a long arc,
in the other. This is effected by combining the electromagnet, the solenoids, the arc
and a rheostat of a proper resistance to a Wheatsone -or Thomson-Wheatstone
bridge in the following manner. The coil of the electromagnet is divided into two
parts between which the end of the bridge wire is connected in which are arranged
the solenoids. The other end of the bridge wire is connected between the rheostat and
the arc.
If the resistances of the two parts of the electromagnet coil are equal, the
bridge wire is without any current only when the resistance of the arc is exactly equal
to that of the rheostat. If the resistance of the arc be smaller or greater than the
resistance of the rheostat, then a current will pass through the bridge wire, with the
solenoids in one or the other direction and a movement will result until the resistances
of the rheostat and the arc are equal again or in the same proportion as one part of
the electromagnet coil to the other and the normal arc is again reached.
From the foregoing it is clear that this regulating system differs materially from
those depending on the direct action of the current, because all these are based on the
differential principle, and the two magnetic momentums, one produced by the primary
and the other by the secondary current, counter balance cach other when the arc is of
normal length. The momentums are therefor equal but of opposite direction.
In this regulating system this balance is produced by the cessation of the current
in one part of the regulating electromagnetic system when the arc is of normal
length.
The system described above has like most others the fault, that the forces of the two
solenoids partly compensate each other in certain positions, whereby the regulating
force is diminished. I have therefor chosen a system in which in no position of the
different parts is the regulating force diminished.
In an are lamp, constructed on this system, two electromagnets are fixed on the
same spindle in such a manner that the corresponding ends have opposite poles they
represent therefor an astatic needle pair and are thus not under the influence of the
earth magnetism. Each of the electromagnets revolves within one or two series of
bobbins wound like those of a galvanoscopic multiplicator so that the whole resembles
a galvanoscope with electromagnets in place of the ordinary astatic steel needles.
The positive carbon holder is attached to the same spindle as the electromagnets and
thus is moved direct with the latter. The negative carbon holder is fixed on a separate
spindle and is moved by two tooth-wheels fixed respectively on the electromagnet
spindle and the separate one. If the lamp is to be confocal the proportion of these
wheels must be as 1 to 2.
If the lamp is operated by currents of the same direction the positive carbon would
throw a strong light cone on to one side of the glass globe and thus produce a very
unsatisfactory diffusion of light. To avoid this the carbons burn within a mantle

page_text: of refractory material conically opened downwards which reflects the light
downwards. This mantle may be of marble, granite, chamotte, or any other suitable
material.
It will be easily understood, that the circular movement of the carbons may be
changed into a linear vertical one by using for example a system of rollers and
cards.
Instead of the double series of bobbins one series only may be used and one electro-
magnet would then move within and the other without the bobbins.
The current in the lamp circuit is divided in two branches, one going through the
rheostat and the arc, the other through the electromagnets; the bobbins are connected
in the bridgewire.
Instead of the ordinary straight electromagnets, circular magnets may be used
having the poles on two opposite points of the periphery. These circular magnets
may be in the form of a ring or a disc, or polygonal. The magnet may also be in horse-
shoe form, only in this instance the bobbins must be so arranged that the plane of the
winding is parallel to the plane of the horseshoe.
The round or polygonal electromagnets mentioned above may be wound in the same
manner as the Paccinotti-Gramone ring and be provided with a collector.
The above described arrangement can however be used in a different manner for
the regulating of the arc. For instance one series of bobbins may be wound with
thin and the other with thick wire and currents are sent through these series of
bobbins in such a direction that they effect the electromagnets in the opposite direction.
The thin wire forms a great number of coils and the thick much less. It is feasible
now that with a certain proportion of the current-forces in the two bobbin series, the
effect is compensated by the electromagnets and equilibrium is produced. In this
arrangement one series of bobbins is connected in the primary current and the other
in the secondary. In this arrangement the lamp acts like a differential lamp; If the
carbons are too near together then the action of the bobbins in the primary current
exceeds and the carbons are moved away from each other; if the arc is becoming too
long the action of the secondary current will exceed and the carbons will be moved
towards each other.
It is not necessary that each series of bobbins be wound with the same size of wire,
but one bobbin of each pair may be wound with thin and the other with thick wire, or
each bobbin may even be partly wound with thin and partly with thick wire, but the
direction of the currents must always be such in the two branches that they act on the
electromagnets in the opposite direction.
The electromagnets may be connected in a shunt as long as they form an astatic
needle pair. If the lamp is in a parallel shunt with the rheostat it is not necessary
to use the primary current for the regulation of the lamp as two secondary currents
will do as well.
the
In this arrangement one pair of bobbins are connected in a secondary current
branching off from the rheostat and the other pair in a secondary current branching
off from the lamp. What has been said about the winding of the bobbins applies here
also and the secondary currents must also be so arranged that they act upon
electromagnets in the opposite direction i.e. the secondary current going through the
rheostat to move the carbons away from each other and the other going through
the lamp to move them towards each other.
The regulating may also be effected by overlapping secondary currents.

page_text: I, ALFRED JULIUS BOULT of 323 High Holborn, in the County of Middlesex,
M.I.M.E. 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:
This invention relates to improvements in regulators for electric arc lights and it
consists essentially in combining the arc light with certain resistances. in such a
manner that systems of electro magnets and solenoids without mechanism can be used
for the direct regulation of the arc light such systems having neither a constant
attraction nor a symmetrical attraction curve; conditions which are essential and
necessary to the regulators hitherto in use.
The regulation of this regulator is perfectly independent of the attraction and only
requires a system of electromagnets and solenoids in which, by reversing the current
in one part thereof, the direction of the movement is also reversed.
The following will explain the above assertions. A Figure 1 is an electromagnet
provided with elongated poles S and N. On these poles two solenoids B C are moving
free, connected with each other by a cord running over the pulleys ab. If a current
is sent through these solenoids in such direction that B at the top has the same pole as
A but C has the opposite, then there will be a movement of the solenoids in the
direction of the arrow.
The force which moves the solenoids is different in different positions of the latter
and this difference has its course in the fact that the forces of the solenoids are
summed together in certain positions but partly compensate each other in others. If
in a diagram the distances of the solenoid B for instance from the electromagnet A are
represented as abscissas and the forces acting upon the solenoids as ordinates the
curve A shown in the diagram Figure 2 would result.
If the direction of the current in the solenoids B C is reversed while it remains the
same in the electromagnet A then the direction of the movement is also reversed.
From this it is easy to see that it is possible to combine such systems of electro-
magnets and solenoids in which, in large circuits, by reversing the current in a part of
the system the direction of the movement is also reversed.
The following is to explain that with a correct reversion of the current such system
can be used for the regulating of arc lights and that such reversion of the current can
be produced automatically without intricate mechanism and without interrupting the
current by a combination of the arc with proper resistances; and this is the principal
point of the present invention..
Firstly it is to be shown how the system can be employed for the regulating of the
arc light. Supposing the two solenoids B and C Figure 3 carry carbon holders mn

page_text: with carbons o, p touching each other and the current is sent through the lamp, the
solenoids must have such poles towards the electromagnet that a movement in the
direction of arrow 1 results, the carbons are thus separated and the are produced. In
the moment when the normal arc is reached the current in the solenoids ceases through
the forces compensating each other, and the movement stops. If the system is
properly adjusted the carbons will remain in this position until they burn away and
the are becomes too long in which case the current is to flow through the solenoids in
the reverse direction resulting in a movement in the direction of arrow 2 and the
carbons are moved towards each other until the normal are is reached again when the
current ceases in the solenoids and the movement stops again.
For the proper operation of the lamp there are therefore three problems to solve i.e.
with the normal length of the are the current in solenoids is to be nil then with a short
are the current must flow through the solenoids in one direction, and with a long arc
in the other. This is effected by combining the electromagnet, the solenoids, the arc,
and a rheostat of a proper resistance to a Wheatstone or Thomson-Wheatstone
Bridge in the following manner.
Figures 4 and 5 represent in a diagram the combination of the different parts.
Figure 4 is a combination for the simple Wheatstone bridge. The coil of the electro-
magnet is divided in two parts A A¹ between which one end of the bridgewire is
connected in which are arranged the solenoids B C. The other end of the bridge
wire is connected between the rheostat R and the arc o p. If the resistances of A A¹
are equal, the bridge wire is without any current only when the resistance of the arc
is exactly equal to that of the rheostat. If the resistance of the arc be smaller or
greater than the resistance of the rheostat then a current will pass through the bridge
wire with solenoids in one or the other direction and a movement will result until the
resistances of the rheostat and the arc are equal again or in the same proportion as
A to A, and the normal arc is again reached. The current is introduced into the
bridge system at a and b..
The diagram Figure 5 only differs from the preceeding in that the coil of the
electromagnet is divided into four parts A' A' A* A*.
From the foregoing it is clear that this regulating system differs materially from
those depending on the direct action of the current because all these are based on the
differential principle and the two magnetic momentums, one produced by the primary
and the other by the secondary current, counterbalance each other when the arc is of
normal length. The momentums are therefore equal but of opposite direction.
In this regulating system this balance is produced by the cessation of the current in
one part of the regulating electromagnetic system when the arc is of normal length.
The system described above has like most others the fault that the forces of the two
solenoids partly compensate each other in certain positions whereby the regulating
force is diminished. I bave therefore chosen a system in which in no position of the
different parts is the regulating force diminished.
The circuit in the lamp is arranged as shown in the diagram Figure 4 or Figure 5;
the current is divided in two branches, one going through the rheostat and the arc,
the other through the electromagnets; the bobbins are connected in the bridge wire.
I therefore use magnetic systems consisting of closed parallelograms or rings of soft
non magnetic iron.
Figure 6 represents a diagram of such an arrangement. The parallellogram abed
is provided on two sides with fixed solenoids A B and on the other two sides with
movable solenoids CD which latter are connected by a cord s running over a roller R.
Through the fixed solenoids a current is sent which converts the side a of the parallelo-
gram into an S pole and the side b into an N pole.
If now a current is sent through the movable solenoids producing poles as shown in
Figure 6 these solenoids will move in the direction of the arrows. If the direction of
the current be reversed in one pair of solenoids only while it remains the same in the
other the direction of the movement of the movable pair of solenoids will also be
reversed.
The carbon holders K K are connected directly with the movable solenoids so that

page_text: they follow the movement. One pair of the solenoids is connected up with the bridge
wire of the wheatstone bridge while through the other pair a current of unchangeable
direction is sent.
As represented in Figure 7 instead of a parallelogram a closed ring F may be used.
In this case the solenoids of each pair are placed diametrically opposite each other
and the movable solenoids C D are conected by an arm H which turns round a central
axis o; under the same conditions the effect is similar to that in Figure 6.
It is not necessary that only the bobbins A and B or C and D should be wound
with wire of the same size; the bobbins A C or A D may be wound with thin and.
BD or B C with thick wire or vice versa or each bobbin may be wound partly with
thin and partly with thick wire but the direction of the currents must always be such in
the two branches that they act on the electromagnets in the opposite direction.
The electromagnets may be connected in a shunt as long as they form an astatic
needle pair. If the lamp is in a parallel shunt with the rheostat it is not necessary to
use the primary current for the regulation of the lamp as two secondary currents
will do as well.
Figure 8 represents this arrangement in diagram. The bobbins A B are connected
in a secondary current branching off from the rheostat at a and b. The bobbins CD
are connected in a secondary eurrent branching off from the lamp at cd. What has
been said about the winding of the bobbins applies here also and the secondary currents
must also be so arranged that they act upon the electromagnets in the opposite
direction i.e. the secondary current a A B b to move the carbons away from each other
and c C D d to move them towards each other.
The regulating may also be effected by over-lapping secondary currents as shown in
diagram in Figure 9.
Having now particularly described and ascertained the nature of the said invention
as communicated to me by my foreign correspondent and in what manner the same is
to be performed, I declare that what I claim is :-
1. In Regulators for the intensity of the electric current in general and especially
for the electric arc light in which the regulating electromagnetic system is equilibrated
by the current ceasing in one part of the electromagnetic system when the intensity of
the current or the arc is normal while the current flows through the same part of the
system in one direction or the other when the arc is too short or too long, the com-
bination of the arc with suitable resistances so as to form a Wheatstone-or Thomson-
Wheatstone-bridge system as represented in the diagrams Figures 4 and 5.
2. For the direct regulating of the electric arc light the employment of a directly
regulating magnetic system, consisting of a parallelogram polygon or ring of soft
non-magnetic iron provided with a pair of fixed and a pair of movable solenoids so
arranged that when the direction of the current is reversed in one of the solenoid pairs
the direction of the motion of the movable solenoids with which the carbon holders are
connected is also reversed substantially as specified.
3. In regulators such as described the method or arrangement for regulating by
two secondary currents only as represented in diagram in Figure 8 without the use of
the primary current in such a manner that one secondary current branches off from
the two opposite sides of a constant resistance and the other current from the sides of
the varying resistance or arc; or as shown in Figure 9 in such a manner that one
secondary current branches off from the beginning of the constant resistance to the
beginning of the varying and the other from the end of the constant resistance to the
end of the varying substantially as specified.
DL: 14th dose of December 1886