Improvements in Apparatus for Regulating Electric Currents.
Year: 1891

page_text: Date of Application, 25th June, 1891
Complete Specification Left, 25th Mar., 1892-Accepted, 7th May, 1892
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Regulating Electric Currents.
I, JULES FERRAND of Darnetal, Department de la Seine Inferieure, France,
Manufacturer, do hereby declare the nature of this invention to be as follows:-
This invention has reference to improvements in apparatus for automatically
regulating electric currents, and is based upon the fact that carbon (coke,
illuminating pencil or agglomerating carbon) varies its electrical resistance in
inverse ratio to the pressure to which it is subjected.
In such apparatus according to this invention, one or more carbon resistances is
or are used, connected for tension or for quantity and composed of pieces of carbon
(hereinafter called carbon plates) that may vary in form, dimensions, and numbers
according to requirements; and which are maintained side by side in a row by an
insulating mount.
The carbon resistance or resistances may be arranged horizontally, inclined, or
vertically. In order to modify the coupling thereof they may each be divided up
or connected together electrically. The pieces of carbon of any form may be solid
or hollow; they may be surrounded by a thin sheet of the same material for
increasing the cooling surface; and they may be formed of blades with wings or
ribs alternating crosswise, and projecting from the insulating mount.
The parts in electrical contact may also be composed of projecting segments in
order to provide passages for air through the row of carbon plates. The parts
designed for cooling may be metallized in order to hasten the cooling.
The regulating apparatus is constructed with an electro magnetic device that
acts automatically with a variable pressure upon the carbon plates when the current
to be regulated varies.
In the following description I will assume that the apparatus is to be employed
for the regulation of a shunt wound dynamo-electric machine used for the produc-
tion of light, and having a single winding on the induction coils. Such machines
are extremely sensitive to the variations of intensity in the main circuit.
My apparatus has for its main object, in this particular case, to regulate
automatically and instantaneously the voltage of the main current whatever its
output in amperes may be. This regulation is effected notwithstanding variations
in the speed of the motor, and independently of the greater or smaller number of
lamps in operation.
These are the conditions of regulation which are the hardest to realize, because
with compound dynamos there remains only to correct the variations in speed.
In the annexed drawings,
Figs. 1 and 2 are respectively a side elevation and a plan of regulating apparatus
constructed according to this invention.
Fig. 3 is a side view partly in section on the line 1-2 of Fig. 1.
K is a base plate supporting a frame I that carries a regulating electro magnet D
and a three arm lever E E² E³. A is a variable carbon resistance composed of a
number of plates of carbon arranged side by side and maintained in position by
three rods a of suitable material as for example glass that are fixed in two
supports a a. The three arm lever E E E³ is mounted to oscillate on an axis e;
the arm E of this lever constitutes the armature of the horizontally arranged
electro magnet D; the arm E³ supports a regulating weight P and the rod of a
brake piston L; and the arm E³ carries a screw threaded rod H which bears
against one end of the row of carbon plates A so as to transmit to these carbon
plates a pressure that will vary in accordance with the variations in the magnetic

page_text: value of the electro magnet D. B is a regulating screw which allows of setting
the apparatus at the voltage which it is desired to maintain. F is an oil brake
consisting of a cylinder containing oil and in which moves a piston L formed with
a hole. O is a screw by which the cross sectional area of this hole can be increased
or diminished.
This brake has for object to render more or less slow the movements of the
lever E E E³ according as the machine to be regulated takes more or less time
to become magnetized. This brake does not interfere with the sensitiveness of the
apparatus, but renders its movements slower according to requirements.
The operation of the apparatus is as follows:-A shunt from the main current
feeds the coil of the regulating electro magnet D and the exciting current passes
through the row of carbon plates A. I will assume that a small dynamo electric
machine is to be regulated so as to give a difference of potential of 100 volts and
a current strength of 10 amperes for feeding 20 lamps. Under these conditions the
regulating electro magnet D will have a magnetic force dependent upon the
resistance of the shunt circuit in which it is placed and upon the construction of
the coil. This magnetic force will maintain the armature E' in a certain position
of equilibrium which corresponds to the necessary pressure on the carbon plates
for obtaining 100 volts and 10 amperes in the main circuit. The apparatus thus
regulated will maintain this difference of potential of 100 volts.
Now if 20 other lamps be placed in circuit the electro motive force of the main
current would, without the regulating apparatus, fall say for instance to 80 volts,
but with my regulating apparatus in circuit as soon as the voltage tends to fall,
the electro magnet D loses a little power, and the weight p will increase the
pressure of the rod H on the carbon plates A. A more intense current will then
pass into the exciting coil; and the voltage in the main circuit will rise to its
original amount, but with a consumption of 20 amperes instead of 10 amperes.
If the machine does not sensibly undergo the phenomena of hysterisis, the effect
is instantaneous and without shock; it is a little slower if the machine is slow in
becoming magnetized.
If for any reason the machine tends to exceed the original electro motive force
or current strength or if the 20 lamps added are cut out, the effect above described
is reversed.
The regulation also takes place when, with the same number of lamps in circuit,
the speed of the dynamo is modified by irregularity in the speed of the motor by
which it is driven.
The apparatus will also operate to effect the regulation when a variation in the
number of the lamps in use and a variation in speed of the dynamo take place
simultaneously.
Regulating apparatus constructed as hereinbefore described can be applied to
dynamo electric machines producing continuous rectified, or alternating currents of
high or low electro motive force and for various purposes as for example for
lighting, transmission of power, and electro-plating.
It may also be used for the regulation of the discharge of batteries and
accumulators, and in all cases where it is required to obtain a complete constancy
in electric currents, as for instance in houses, shops, hotels, theatres, and public
buildings, whether fed by their own source of electric supply, or from an electrical
station for correcting variations in the amount of power transmitted or illumination
produced in electrical stations for rendering more regular the source of the
currents supplied to subscribers, and in telegraph or telephone stations, &c.
;
For electrical motors, the apparatus can be used to regulate the motor for
constant power and speed, or for variable power with constant speed.
The carbon plates may also be employed without the regulator where it is
required to vary at will the operation of an electrical apparatus, as for instance, for
electrical ringing apparatus, which will have more or less energy according as the
pressure exerted on the knob shall be greater or smaller than the normal amount;
for causing electric lamps to burn after the manner of night lights, and so that

page_text: they will regain their brightness when the carbon plates are subjected to pressure,
or for equalizing lamps the resistance of which is not the same.
Dated this 25th day of June 1891
J. FERRAND,
By L. W., per F. B.
COMPLETE SPECIFICATION.
Improvements in Apparatus for Regulating Electric Currents.
I, JULES FERRAND of Darnetal, Department de la Seine Inferieure, France,
Manufacturer, 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 has reference to apparatus for automatically regulating electric
currents, and is based upon the fact that carbon (coke, illuminating pencil or
agglomerated carbon) varies its electrical resistance in inverse ratio to the pressure
to which it is subjected.
In such apparatus according to this invention one or more carbon resistances is or
are used, connected for tension or for quantity, and composed of pieces of carbon
(hereinafter called carbon plates) that may vary in form, dimensions, and numbers
according to requirements, and which are maintained side by side in a row by an
insulating mount.
The carbon resistance or resistances may be arranged horizontally, inclined, or
vertically. In order to modify the coupling thereof, they may each be divided
up or connected together electrically. The carbon plates may be of any form,
solid or hollow; they may be surrounded by a thin sheet of the same material for
increasing the cooling surface; and they may be formed of blades with wings or
ribs arranged to alternate with each other and to project from the mount.
The carbon plates may also be formed with projections in order to provide
passage for air through the row of carbon plates. The parts designed for cooling
may be metallized in order to hasten the cooling action.
The regulating apparatus is constructed with an electro-magnetic device that acts
automatically with a variable pressure upon the carbon plates when the current to
be regulated varies. In the following description I will assume that the apparatus
is to be employed for the regulation of a shunt wound dynamo electric machine
used for the production of light and having a single winding on the induction
coils. Such machines are extremely sensitive to the variations of intensity in the
main circuit.
My apparatus has for its main object, in this particular case, to regulate
automatically and instantaneously the voltage of the main current whatever the
output of the machine in amperes may be. This regulation is effected notwith-
standing the variations in the speed of the motor, and independently of the greater
or smaller number of lamps in operation.
These are the conditions of regulation which are the hardest to realize, because
with compound wound machines all that remains to be done is to correct the
variations in speed.
In the annexed drawings,
Figs. 1 and 2 are respectively a side elevation and a plan of regulating apparatus
constructed according to this invention.
Fig. 3 is an end view partly in section on the line 1-2 of Fig. 1.
K is a base plate supporting a frame I, that carries a regulating electro magnet D
and a three arm lever E¹ E² E³. A is a variable carbon resistance composed of a
number of discs or plates of carbon arranged side by side and maintained in position
by three rods a of suitable material, as for example glass, that are fixed in two
supports a a. The carbon plates of the resistance A may be separated by metal
plates varying in form and nature according to requirements.

page_text: The three arm lever E' E' E' is mounted to oscillate on an axis e. The arm E
of this lever constitutes the armature of the electro-magnet D; the arm
supports a regulating weight P and the rod of a brake piston L; and the
arm E³ carries a screw threaded rod FI which bears against one end of the row
of carbon plates A so as to transmit to these carbon plates a pressure that will
vary in accordance with the variations in the magnetic value of the electro
magnet D.
B is a regulating screw which admits of the apparatus being set to
regulate at the voltage which it is desired to maintain. F is an oil brake consisting
of a cylinder containing oil, and in which moves the piston L which is formed with
a hole. O is a screw by which the cross sectional area of this opening can be
increased or diminished.
The brake has for object to render the movements of the lever E E E³ more
or less slow according as the machine to be regulated takes more or less time to
become magnetized. This brake does not interfere with the sensitiveness of the
apparatus but renders its movements slower according to requirements.
The operation of the apparatus is as follows:-
A shunt current from the main circuit passes through the coil of the regulating
electro magnet D and the exciting current for the field magnet of the dynamo to
be regulated passes entirely through the row of carbon plates A. It enters by the
conductor C and regulating screw B and passes out again by the screwed rod H,
the lever E E E³, the support for the lever and the terminal (for attachment of
the circuit wire.
I will assume that a small dynamo electric machine is to be regulated so as to
give a difference of potention of 100 volts and a current strength of 10 amperes for
feeding twenty lamps. Under these conditions the regulating electro magnet D
will have a magnetic force dependent upon the resistance of the shunt circuit in
which it is placed and upon the construction of its winding.
This magnetic force will maintain the armature E in a certain position of
equilibrium which corresponds to the necessary pressure on the carbon plates for
obtaining a difference of potential of 100 volts and a current of 10 amperes in the
main circuit. The apparatus thus regulated will maintain this difference of potential
of 100 volts. If twenty other lamps be placed in circuit, the electro motive force
of the main current would, without a regulating apparatus fall, say for instance to
80 volts, but with my regulating apparatus in circuit as soon as voltage tends to
fall, the electro magnet D loses a little of its magnetic power, and the weight P
will increase the pressure of the rod H on the carbon plates A. A more intense
current will then pass through the exciting coil of the field magnet of the dynamo
machine and the voltage in the main circuit will rise to its original value, but with
an output of twenty amperes instead of 10 amperes.
If the dynamo machine does not sensibly undergo the phenomena of hysteresis,
the regulating effect will be instantaneous and without shock; it will however be a
little slower if the machine is slow in becoming magnetised.
If the voltage of the dynamo machine, for any reason, tends to exceed the normal,
or if the twenty lamps added are cut out of circuit the effect above described will
be reversed.
The regulation also takes place when, with the same number of lamps in circuit,
the speed of the dynamo becomes modified by irregularities in the speed of the
motor by which it is driven.
Finally by the same means the apparatus will also operate to effect the regulation
when a variation in the number of the lamps in use, and a variation in speed of the
dynamo take place simultaneously.
Regulating apparatus constructed as hereinbefore described can be applied to
dynamo electric machines producing continuous commuted, or alternating currents
of high or low electro motive force, and for various purposes, as for examples for
lighting, transmission of power, and electro plating.
It may also be used for the regulation of the discharge of galvanic batteries and
accumulators, and in all cases where it is required to obtain complete constancy

page_text: of the electric currents dealt with, as for instance in houses, shops, hotels, theatres
and public buildings whether fed by their own source of supply, or from an
electrical station for correcting variations in the amount of power transmitted or
illumination produced in electrical stations for rendering more regular the source
whence currents are supplied to subscribers; and in telegraph or telephone
stations etc.
For electrical motors, the apparatus can be used to regulate the motor for
constant power and speed, or for variable power with constant speed.
The carbon plates may also be employed without the regulator where it is
required to vary at will the operation of an electrical apparatus, as for instance for
electrical ringing apparatus, which will then have more or less energy according as
the pressure exerted on the knob shall be greater or smaller than the norinal
amount; for causing electric lamps to burn after the manner of nightlights, and so
that they will regain their brightness when the carbon plates are subjected to
pressure; and for equalizing lamps the resistances of which are not equal.
With the object of not allowing all the current to pass through the carbon
plates of the regulating apparatus whilst leaving to the latter the capability of
maintaining the voltage as described, employ one or other of the arrangements
illustrated in Fig. 4 or in Figs. 5 and 6 of the accompanying drawings. This
result is obtained: First as shewn in Fig. 4, by arranging in the circuit with the
conductor C by which the current is passed into and out of the regulating
apparatus, wherein A is the carbon resistance, a fixed shunt c having a resistance r
whereby a portion of the current that does not need to be regulated as for instance
in dynamo machines, the portion necessary for exciting the machine when running
with an external load, can be shunted past the regulating apparatus. The current
necessary for feeding the machine, according to the required output thereof will
pass through the carbon resistance A.
Second. By employing a series of shunts designed to allow a current of only a
small number of ainperes to pass even when the current to be regulated would be
much more important.
For this purpose a series of electro magnets E E E E³ (Figs. 5 and 6) are
provided, through the coils of which all the current to be regulated would pass.
The armatures e e e e³ of these electro magnets are arranged to be attracted by
the corresponding electro magnet so as to establish a short circuit through the
fixed resistances. These circuits, are made of gradually decreasing length
and will be graduated in such a manner as to allow 5 amperes for instance, to pass
through into each shunt.
The armatures are weighted in such a manner that the first will rise by the
passage through its electro magnet of a current of 7 amperes; the second by the
passage of a current of 12 amperes, and so on.
The reverse operation will be effected when the current to be regulated diminishes
in intensity.
The two amperes forming the total of 7 with the 5 amperes passing in the first
shunt or the total of 12 with twice 5 amperes passing in the first and second
shunt etc. will pass through the carbon. This is the minimum number of amperes
with which the regulator will act to maintain the voltage, in the example taken.
The arrangement shewn. diagrammatically in Figs. 5 and 6 consists of three
shunts the two first being similar to that in the arrangement shewn in Fig. 4;
and the third c¹ passing to all the supports S of the armature e which are in
electrical connection with each other.
The circuit is closed by means of the terminals bh₁ which are insulated
from each other and are placed in connection with the resistances r²² på
respectively as shewn.
The current can only pass through the shunts c or c¹ when the armature e is raised
by its electro magnet. V is a screw that bears against the terminal b and
completes the short circuit when the armature e is raised.
Each of the armatures is so regulated, either by placing it near to or further

page_text: from its electro magnet or by means of a weight, that it acts only when a current
of a definite amount passes through its corresponding electro-magnet so that a
different magnetic force is required for operating each of them. The part of the
current that passes through the shunt circuit or circuit and also that which passes
through the carbon resistance A unite in a single wire and traverses the winding
of all the electro magnets.
Fig. 6 illustrates the arrangement of a short circuit by one of the armatures.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. Apparatus for automatically regulating electric currents, comprising a number
of carbon blocks or plates arranged to form part of an electric circuit, an electro-
magnetic device adapted to be energised by the action of the current to be
regulated, and mechanism capable of being actuated by the said electro magnet to
press the carbon blocks or plates together with a force that will vary in accordance
with the degree of excitation of the said electro-magnetic device substantially as
hereinbefore described for the purpose specified.
2. Apparatus for automatically regulating electric currents, comprising one or
more columns or rows of carbon discs or plates capable of being traversed by the
whole of the field magnet exciting current in the case of a dynamo electric
machine, or in the case of a primary or secondary battery, by the whole of the
current produced by such battery, an electro-magnet the windings of which is
capable of being traversed by a shunt circuit from the main circuit the electro
motive force in which is to be controlled, and a lever having three arms of which
one constitutes the armature of the said electro-magnet, another is provided with a
weight and the third is arranged to transmit pressure to the said carbon discs or
plates during the operation of the regulating apparatus, the arrangement being
such as to automatically diminish the resistance of the column or row of carbon
disc or plates when the electro motive force of the main current tends to fall and
to increase the resistance upon the electro motive force tends to rise substantially
as hereinbefore described.
3. In apparatus of the kind referred to in the preceding claim a liquid brake
comprising an oil cylinder fitted with a piston connected to one arm of the three
armed lever and formed with an opening the size of which can be varied the
arrangement being such that the rapidity of movement of the said, lever can be
controlled to suit requirement substantially as herein before described.
4. Regulating apparatus of the kind herein referred to, constructed with one or
more shunt circuits whereby a portion of the current to be regulated can be
shunted past the carbon resistance whilst leaving the latter free to maintain the
electro motive force of the current, as hereinbefore described with reference to and
shown in Fig. 4 and in Figs. 5 and 6 of the drawings.
Dated this 25th day of March 1892.
JULES FERRAND,
By L. W., per F. B.