Improvements in Electric Arc Lamps.
Year: 1890

page_text: Date of Application, 27th Dec., 1890
Complete Specification Left, 28th Sept., 1891-Accepted, 31st Oct., 1891
PROVISIONAL SPECIFICATION.
Improvements in Electric Arc Lamps.
We, ALBERT GAY of 47 Gloucester Road, Brighton, in the County of Sussex,
Electrical Engineer, and ROBERT HAMMOND of 117 Bishopsgate Street, Within,
in the County of London, Electrical Engineer, do hereby declare the nature of this
invention to be as follows:
In the Specification of an application for Letters Patent filed by us on the
31st March 1890 No. 4991 there is described a construction of electric are lamp in
which the position of the carbons is regulated by two electric motors one of which
is in the main circuit of the lamp whilst the other is in a shunt circuit around the.
arc, the two motors being so arranged that they oppose each other and produce a
condition of equilibrium when the arc is of normal length.
Now this invention has reference to improvements in lamps of the kind referred
to whereby the tendency of the carbons to be sometimes forcibly moved into
contact by the shunt motor and to remain in contact for a time due to this motor
racing on first lighting up, (thereby producing a large increase of current through
the lamp) is prevented. To prevent the shunt motor racing, a brake is provided to
retard the rotation of the shaft driven by the two motors. An arrangement for
this purpose comprises a number of spring arms or blades fixed to the motor shaft
and into the path of which an arın or abutment is brought when the carbons come
into contact and cause an excessive current to pass.
This arm or abutment is moved into its operative position by the core of a
solenoid in the circuit of the series motor and into its inoperative position by a
spring or equivalent or this arrangement may be reversed. In one arrangement
the arm or abutment is pivotted to the core in such a manner that it can turn and
offer comparatively small resistance to the motion of the spring arms or blades
when these are rotated by the series motor, but will be held rigid so as to offer
considerable resistance to the motion of the spring arms or blades when these are
moved in the opposite direction by the shunt motor.
The field coil of the shunt motor is so arranged that when the arc of the lamp
becomes too long and the armature of this motor tends to rotate so as to bring the
carbons nearer together, the action of the field coil on the armature is increased so
as to assist the motion of the armature and increase the action of the motor to
shorten the arc.
To this end instead of fixing the closed field coil that encircles the armature of
the shunt motor as in the lamp described in our said former Specification, we
mount it in such a manner that it can partly turn around the armature and so vary
the strength of the motor. The coil is connected at one side of its pivot to the
core of a solenoid arranged either in the series or in the shunt circuit, and at the
other side to a spring or its equivalent, the arrangement being such that when
the rotative force of the shunt motor armature tends to overcome that of the series
motor armature, the solenoid will cause or allow the core to move the closed
magnet coil partly around the shunt motor armature in such a direction as to
increase the speed and regulating action of this armature.
In a modified construction of lamp the shunt motor is dispensed with, and the
carbons are brought together by gravity or other means when the lamp ceases
working. In this construction the closed field coil around the armature of the
series motor is pivotted, and so arranged, that when the lamp is burning with its
normal length of are, it will assume a position in which the rotative power of the
motor will be balanced by the weight of the carbons, carbon holders and attached
parts.

page_text: When the closed field coil is moved in: one direction from the neutral position
the armature will commence to rotate and move the carbons apart, and when it is
moved in the opposite direction from the neutral position, the armature will rotate
in the reverse direction, and bring the carbons together. The closed field coil is
moved in one direction by the core of a solenoid placed in the circuit of the lamp,
and in the reverse direction by a spring or equivalent. The motion of the armature
can be transmitted to one or both of the carbon holders by any suitable means such
as a pulley and a cord or cords.
The lamp may be modified so as to work as a shunt lamp having a shunt motor
only; the rocking closed coil being controlled by a solenoid either in the shunt
circuit or in series with. the carbons. In this case the carbons will move apart by
gravity when perimitted to do so by the shunt motor.
Dated this 27th day of December 1890.
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicants.
COMPLETE SPECIFICATION.
Improvements in Electric Arc Lamps.
We, ALBERT GAY formerly of 47 Gloucester Road, Brighton, in the County of
Sussex, liut, now of Kensington Central Electric Lighting Station, Richmond
Road, SW, in the County of London, Electrical Engineer, and ROBERT
HAMMOND of 117 Bishopsgate Street, Within, in the County of London,
Electrical Engineer, do hereby declare the nature of this invention and in what
manner thie-same is to be performed to be particularly described and ascertained in
and by the following statement:—
In the Specification of an application for Letters Patent filed. by us on the
31st March 1890 No. 4991 there is described a construction of electric arc lamp in
which the position of the carbons is regulated by two electric motors one of which
is in the main circuit of the lamp whilst the other is in a shunt circuit around the
arc, the two motors, being so arranged that they oppose each other and produce a
condition of equilibrium when the arc is of normal length.
Now this invention has reference to improvements in lamps of the kind referred
to whereby the tendency of the carbons to be sometimes forcibly moved into
contact by the shunt motor and to remain in contact for a time due to this motor
racing, on first lighting up, (thereby producing a large increase of current through
the lamp) is prevented. To prevent the shunt motor racing, a brake is provided to
retard the rotation of the shaft driven by the two motors. An arrangement for
this purpose comprises a number of spring arms or blades fixed to the motor shaft
and into the path.of which an. arm. or abutment is brought when the carbons come
into contact, and cause an excessive current to pass.
This arm or abutment is moved into its operative position by an electro magnetic
device such as the core of a solenoid in the circuit of the series motor and into its
inoperative position by a spring or equivalent, or this arrangement may be reversed.
In one, arrangement the arm or abutment is pivoted to the core in such a manner
that it can turn and offer comparatively small resistance to the motion of the spring
arms or blades when these are rotated by the series motor, but will be held, rigid. so
as to offer considerable resistance to the motion of the spring arms or blades when
these, are moved in the opposite direction by the shunt motor.
Referring to the accompanying drawings,
Figs. 1 and 2 are two elevations at right angles to each other shewing a part of
an electric arc lamp provided with a brake according to this part of my invention.
1 and 2 indicate the armatures of two electric motors; they are mounted on one
spindle 3,, on which is also a brake comprising a number of spring, blades. 5,. 5.
Below the spindle, and almost in the path of the spring blades 5, 5, is an arm. or

page_text: abutment 6, capable of being moved to and fro sideways. It is connected to the
core 7. of a solenoid 8 which is situated in the circuit of the series motor. This
core is moved in one direction when there is an excessive current in the solenoid,
and is drawn in the opposite direction by a spring 9 when the current decreases.
When the core is drawn in by the solenoid the arin or abutment 6 is moved into
the path of the spring blades 5, 5. If the blades are rotating in the direction of
the arrow, the arm or abutment 6 is pushed over and opposes but little resistance
to their progress, while if they are rotating in the opposite direction the arm or
abutment is rigid. A spring 10 serves to raise the arm 6 which, is pivoted at 11.
The field coil of the shunt motor is so arranged that when the arc of the lamp
becomes too long and the armature of this motor tends to rotate so as to bring the
carbons nearer together, the action of the field coil on the armature is increased so
as to assist the motion of the armature and increase the action of the motor to
shorten the arc.
To this end instead of fixing the closed field coil that encircles the armature of
the shunt motor as in the lamp described with reference to and shown in Figs. 1, 2
and 3 of our said former Specification, we mount it in such a manner that it can
partly turn around the armature and so vary the strength of the motor. This
arrangement as well as a brake such as hereinbefore described, is shown diagram-
matically in Fig. 3. 12 is the closed field coil; it is connected at one side of its
pivot to an electro magnetic device such as the core 13 of a solenoid 14 arranged
either in the series or in the shunt circuit, as may be found most convenient, and at
the other side to a spring 15 or its equivalent: In the arrangement shown, the
solenoid 14 is placed in the series or main circuit of the lamp, but when it is placed
in the shunt circuit the points of connection of the core 13 and spring 15 with the
coil 12 are reversed. The arrangement in each case being such that when the
rotative force of the shunt motor armature 2 tends to overcome that of the series
motor armature 1, due to the lengthening of the are, the solenoid 14 will allow or
cause the core (according as it is in series or in the shunt circuit) to move the
closed' field magnet coil 12 partly around the shunt motor armature in the direction
of the arrow and thereby increase the speed and regulating action of this armature.
In a modified construction of lamp the shunt motor is dispensed with, and the
carbons are brought together by gravity or other means when the lamp ceases
working. In this construction the closed field coil around the armature of the series
motor is pivoted and so arranged, that when the lamp is burning with its normal
length of are, it will assume a position in which the rotative power of the motor
will be balanced by the weight of the carbons, carbon holders and attached parts.
When the closed field coil is moved in one direction from the neutral position
the armature will commence to rotate and move the carbons apart, and when it is
moved in the opposite direction from the neutral position, the armature will rotate
in the reverse direction, and bring the carbons together. The closed field coil is
moved in one direction by the core of a solenoid placed in the circuit of the lump, and
in the reverse direction by a spring or equivalent. The motion of the armature
can be transmitted to one or both of the carbon holders by any suitable means such
as a pulley and a cord or cords.
Figs. 4 and 5 are two elevations at right angles to each other illustrating the
construction of an electric are lamp according to this invention in which the shunt
motor is dispensed with and the carbons are brought together by gravity.
16 is the upper carbon suspended by a cord or chain from a drum or pulley 17,
driven by pinion and wheel from the spindle 3, on which is the armature 1, of a
series motor. The field coil 18 of this motor, with its two polar extensions 19, 19 is
fixed to the framing. 20 is a closed coil surrounding the armature 1, in the manner
usual in alternate current motors of the type shown; it is pivoted to the spindle 3
and is subject on one side of the spindie to the pull of the core 21 of the solenoid 22,
and on the other side of the spindle to the pull of the spring 23. When the lamp
is burning with its normal length of are the coil 20 assumes a position in which the
rotative power of the motor is balanced by the weight of the carbons, and attached

page_text: parts. When the are is too long the spring 23 will overcome the pull of the
solenoid 22, and the closed coil 20 will be turned into its neutral position allowing
gravitation to bring the carbons together. When the are is too short the closed
coil will be turned in a direction to cause the armature to revolve and move the
carbons apart.
The lamp may be modified as shewn in the diagrammatic view Fig. 6 so as to
work as a shunt lamp having a shunt motor only, the rocking closed coil 20 being
controlled by a solenoid 22 either in the shunt circuit as shewn or in series with the
carbons. In this case the weight of the lower carbons and attached parts will be
so arranged that when the arc is too short, the closed coil 20 is pulled into its neutral
position, and the carbons will fall apart. When the arc is too long the closed cuil
will be pulled round into such a position as will cause the armature to rotate and
bring the carbons nearer together.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed we declare that what we
claim is
1. In an electric arc lamp in which the position of the carbons is regulated by
one or more rotary electric motors, the combination of an elastic brake with an
arm or abutment which is moved into and out of engagement with the said elastic
brake by means of an electro-magnetic device substantially as described and for
the purposes specified.
2: In an electric arc lamp in which the position of the carbons is regulated by an
alternate current motor, a closed coil surrounding the armature of such motor, and
capable of being moved in relation thereto, in combination with an electro-magnetic
device which alters the position of the coil according to the amount of current
circulating in the said device.
·
3. In an electric are lamp of the kind herein referred to wherein the position of
the carbons is regulated by two alternate current motors, a series motor and a shunt
motor, pivotting the closed field coil of the shunt motor and connecting it to an
electro-magnetic device arranged either in the series circuit or in the shunt circuit,
so that when the rotative force of the shunt motor tends to overcome that of the
series motor the pivoted closed field coil will be moved partly around the armature
of the shunt motor in a direction to increase the speed and regulating action of this
motor substantially as hereinbefore described.
4. An electric are lamp in which the position of the carbons is regulated by a
single alternate current motor having an armature provided with a rocking closed
field coil controlled by an electro-magnetic device, the arrangement being such that
when the arc is of normal length the closed field coil will assume a position in
which the rotative force of the motor will be balanced by the weight of the carbons
and attached parts, and when such coil is moved in one direction from the neutral
position by the said device the armature will commence to rotate in one direction
and move the carbons apart, and when moved in the opposite direction from the
-neutral position the armature will rotate in the reverse direction and bring the
carbons together substantially as hereinbefore described.
5. The improved electric arc lamp for alternating electric currents constructed
and operated substantially as hereinbefore described with reference to and shown
in Figs. 4 and 5 of the accompanying drawings or modified according to Fig. 6.
Dated this 28th day of Santambor 1001
W. Lloyd Wise,
ALBERT GAY,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicants.