Year: 1887

page_text: Date of Application, 18th Apr., 1887
Complete Left, 9th Jan., 1888
Complete Accepted, 24th Feb., 1888
We, ALEXANDER SIEMENS of 81 Kensington Gardens Square Bayswater in the
County of Middlesex, Civil Engineer, and EDWARD FREDERICK HERMANN HEINRICH
LAUCKERT of Charlton in the County of Kent, Electric Engineer, do hereby declare
the nature of this invention to be as follows:-
This invention relates to apparatus arranged in combination with a dynamo-electric
machine and its circuit supplying electric lamps or other instruments, for the purpose
of controlling the electrical circuit, maintaining the current constant or maintaining
a constant difference of potential in the main leads, notwithstanding variations in the
number of lamps or instruments connected with it. The apparatus for this purpose,
when it is applied to control a current supplying a number of arc lamps or other
apparatus in series is of the following description. The lamps being in the main
circuit of the dynamo-machine, whilst the field magnets of the machine are in a shunt
circuit, the current is regulated by introducing into this shunt circuit more or less
resistance according as there is a smaller or a greater number of lamps or other
apparatus in the main circuit. For this purpose, the main current is led through the
coil of a regulating solenoid having a moveable core suitably counterpoised. The core,
when it moves in obedience to an increased or diminished attraction of the solenoid,
makes one or other of two sets of contacts, bringing into circuit a small electric motor
machine the armature of which is thus caused to revolve in the one direction or the
other. This armature by means of suitable gearing, gives comparatively, slow rotation
to a commutator having its plates connected to a number of resistances arranged in
series. A brush or collector bearing on those plates is connected to one of the
terminals of the main dynamo machine, whilst the first of the plates is connected to
the other terminal through the coils of the field magnets of the machine. According as
the commutator is turned more or less round by the action of the motor a greater or less
number of resistances are introduced into the shunt circuit of the field magnets, and
thus the current generated by the dynamo machine is kept constant notwithstanding
variations in the number of lamps or other apparatus which it supplies. When the
main current is alternating, supplied from the armature of an alternate current

page_text: machine, the field magnets of which are excited by a separate dynamo machine, a
similar arrangement of resistances is applied to the shunt field magnet circuit of this
separate dynamo machine, the regulating solenoid being however excited by the
alternating current that is to be controlled.
When it is required to maintain a constant difference of potential in the main leads,
the regulating solenoid is wound with a coil of fine wire in a shunt circuit from the
main dynamo machine or from the separate dynamo machine used for exciting the field
magnets of the alternate current machine. Instead of employing one reversible
regulating motor, two such motors may be employed, the one serving to turn the
resistance commutator in the one direction and the other to turn it in the opposite
direction.
Obviously, instead of the resistance commutator being turned, it may be stationary,
whilst its brush or collector is turned. The contacts effected by the movement of the
core of the regulating solenoid may be so arranged that the greater the movement of
the core the greater is the amount of current transmitted to work the regulating
motor, and consequently the more rapidly is its armature driven to effect the required
regulation.
1
101 1
г •
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page_text: We, ALEXANDER SIEMENS, of 81 Kensington Gardens Square, Bayswater, in the
County of Middlesex, Civil Engineer, and, EDWARD FREDERICK HERMANN HEINRICH
LAUCKERT, of Charlton, in the County of Kent, Electric Engineer, 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 apparatus arranged in combination with a dynamo electric
machine and its circuit supplying electric lamps or other instruments for the
purpose of controlling the electrical circuit, maintaining the current constant or
maintaining a constant difference of potential in the main leads notwithstanding
variations in the number of lamps or instruments connected with it.
The apparatus for this purpose when it is applied to control a current supplying
a number of arc lamps or other apparatus in series is of the following description.
The lamps being in the main circuit of the dynamo machine, whilst the field
magnets of the machine are in a shunt circuit, the current is regulated by introducing
into this shunt circuit more or less resistance according as there is a smaller or a
greater number of lamps or other apparatus in the main circuit.
For this purpose the main current is led through the coil of a regulating solenoid
having a moveable core suitably counterpoised. The core, when it moves in obedience
to an increased or diminished attraction of the solenoid makes one or other of two
sets of contacts bringing into circuit a small electric motor machine the armature of
which is thus caused to revolve in the one direction or the other. This armature by
means of gearing gives comparatively slow rotation to a commutator having its plates
connected to a number of resistances arranged in series. A brush or collector bearing
on those plates is connected to one of the terminals of the main dynamo machine,
whilst the first of the plates is connected to the other terminal through the coils of
the field magnets of the machine.
According as the commutator is turned more or less round by the action of the
motor a greater or less number of resistances are introduced into the shunt circuit of
the field magnets and thus the current generated by the dynamo machine is kept
constant notwithstanding variations in the number of lamps or other apparatus which
it supplies.
When the main current is alternating, supplied from the armature of an alternate
current machine the field magnets of which are excited by a separate dynamo machine
a similar arrangement of resistances is applied to the shunt field magnet circuit of
this separate dynamo machine, the regulating solenoid being however excited by the
alternating current that is to be controlled.
When it is required to maintain a constant difference of potential in the main leads

page_text: the regulating solenoid is wound with a coil of fine wire in a shunt circuit from the
main leads. The regulating motor is worked by the current in a shunt circuit
from the main dynamo machine or from the separate dynamo machine used for
exciting the field magnets of the alternate current machine."
Instead of employing one reversible regulating motor, two such motors may be
employed, the one serving to turn the resistance commutator in the one direction and
the other to turn it in the opposite direction. Obviously instead of the resistance
commutator being turned, it may be stationary whilst its brush or collector is
turned.
•
The contacts effected by the movement of the core of the regulating solenoid may be
so arranged that the greater the movement of the core the greater is the amount of
current transmitted to work the regulating motor and consequently the more rapidly
is its armature driven to effect the required regulation.
Fig. 1 of the accompanying drawings illustrates diagrammatically an arrangement
according to this invention suited for supply of a number of arc lamps or other
apparatus requiring a constant current. D is the main dynamo machine with
terminals TT from which there is a shunt circuit including the field magnet coils of
the small electric motor M having its terminals t t¹ and on its axis a worm W gearing
with a wheel having an arm which moves over contacts for a number of resistances R.
B is the regulating solenoid with its core P linked to one end of the beam F to the other
end of which is linked the counterpoise CP. An arm G projecting down from the
beam F is linked to a vertical arm L of a rocking shaft E from which four wires
project bending down into mercury cups C₁ C, CC₁. The current from T passes
through the lamps and the coil of the solenoid back to T₁. When the current
increases the core P is drawn down canting the beam F and the rocking shaft E
and causing the wires to he immersed in the mercury cups C₂ C. A current
from T is thus passed through C, to t and from through C to T¹ causing the
worm W of the motor M to revolve and drive the worm wheel in one direction so
that its arm S introduces an increased number of the resistances R into the field
magnet circuit of the dynamo machine D until the current is brought back to its
normal strength. When, on the other hand, the current from the dynamo decreases,
the core P is raised by the counterpoise CP and the rocking shaft E is canted so as
to immerse the wires in C, C₂. A current from T then passes through C³ to t¹ and
from through C, to T causing the worm W of the motor M to revolve in the
opposite direction, and the arm S to move so as to lessen the number of the resistances R
included in the field magnet circuit of the dynamo machine D until the current is
restored to its normal strength.
In Fig. 2 which illustrates an arrangement for maintaining a constant difference of
potential in the main leads, the connections are the same as in Fig. 1 except that the
coil of the solenoid B is in a shunt from the main leads.
Fig. III illustrates an arrangement for regulating the current supplied by an
alternate current machine A, the field magnets of which are excited by the current
from the dynamo machine D). According as the solenoid B is more or less excited
by the currents from A, the dynamo D has its current lessened or increased as
described with reference to Fig. 1 thereby lessening or increasing the action of the
field magnets of A and thus regulating the current from A. In cases where the
difference of potential in the leads for the alternate current is to be kept constant,
the coil of the solenoid B instead of being included in the main circuit of A as
indicated in Fig. III is in a shunt therefrom in a manner similar to that shown
in Fig. II.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed we declare that what we
claim in respect of apparatus for controlling electrical currents is :-
1. In combination with a dynamo machine having its field magnet coils in a shunt
circuit, resistances a greater or less number of which is included in that shunt

page_text: circuit by the movement of a contact arm according as an electro motor which moves
the arm is worked by a current from the dynamo machine in the one direction or the
other as determined by contacts actuated by the greater or less attraction on the core
of a solenoid that has its coil in the main circuit of the dynamo machine, substantially
as described with reference to Fig. 1 illustrating the combination applied to maintain
constant current.
2. The combination stated in the preceding claim modified by having the coil of the
regulating solenoid in a shunt from the main circuit, substantially as described with
reference to Fig. II illustrating the combination applied to maintain constant difference
of potential in the main leads.
3. The combination stated in the first claim modified by having the coil of the
regulating solenoid in the circuit of an alternate current machine which has its field
magnets excited by the dynamo machine regulated as above for constant current
substantially as described with reference to Fig. III illustrating the combination
applied to maintain constant current in the circuit of the alternate current machine.
4. The combination stated in the third claim modified by having the coil of the
regulating solenoid in a shunt from the circuit of the alternate current machine for
the purpose of maintaining constant difference of potential in the leads of the alternate
current machine, substantially as described.