Improvements in or in connection with Constant Current Generation and Regulation.
Year: 1897

page_text: Date of Application, 13th Apr., 1897-Accepted, 29th May, 1897
:
COMPLETE SPECIFICATION.
Improvements in or in connection with Constant Current
Generation and Regulation.
A communication by THOMAS H. HICKS, of 48 Brackenridge Street, Fort
Wayne, in the County of Allen and State of Indiana, and T. STEWART
WHITE, of 915 Michigan Trust Building, Grand Rapids, in the County of
Kent and State of Michigan, and THOMAS FRIANT, all of 915 Michigan Trust
Building aforesaid, United States of America.
1, WILLIAM PHILLIPS THOMPSON F.C.S., M.I.M.E., of The Agency for
Foreign Patent Solicitors, 6 Lord Street, Liverpool and 6, Bank Street,
Manchester, both in the County of Lancaster, 118 New Street, Birmingham in
the County of Warwick and 322 High Holborn in the County of Middlesex,
Civil 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 a system of constant current generation and
regulation.
Figures 1, 2 and 3 are side elevations of three different modifications;
Figure 4 is a detailed plan of a brush holder and its controlling device which is
used with either of the constructions shown in Figures 1, 2 and 3;
Figure 5 is a plan of a magnet discharger which may he applied to either the
field magnets or the solenoid helix or core;
Figure 6 is a diagram view showing how the field magnet coils E E of the two
generators G G may be connected together in multiple are with a switch placed
in either circuit for cutting in or out resistance to divert the right amount of
current through either field coil for the purpose of balancing the field magnet
strength of the two generators.
The scheme is best carried out in the construction shown in Figure 1 which
includes that portion shown in detail in Figure 4.
A represents a shaft. B is an armature. C is a commutator and C'C' its
brushes. D is a pole piece of a field magnet D'. E E' and E2 are. field magnet
coils. Fis a work circuit.having translating devices F' arranged therein in linear
series. G is a generator for supplying the work circuit with current.
G' is a
second regulating generator; in Figure 3, the two generators are combined
in one.
H is a resistance and H' is a switch for cutting in or out resistance. I is a brush
arm having attached at either end a solenoid core I¹ which operate in solenoid
helices J. K are counter springs attached to the solenoid cores. L is a special
discharge coil which may be applied to either the field magnets or the solenoids.
The arrangement and combination of parts above referred to will now be
described together with their functions, whereby new and valuable results are
produced.
Starting with Figure 1:
The coils E of the generators G and G₁ are connected in linear series through
the armature of the generator G and work circuit F. The two generators, in this
case, are excited to primary action by the current which flows through the work
circuit. The armature of the regulating generator Glis.closed in its circuit through

page_text: the coil E of the work circuit generator G, and the current is caused to How
through the coil E' in such a direction as to tend to neutralise the effect of the
current which flows through E of generator G. This coil. El is, therefore, a
differential coil. Of course, if the current flowing through coil E' were to entirely
neutralise the effect of the current which flows through the coil E of the work
circuit generator G, then the generator G would be inoperative. But the coils E
and E are so proportioned to each other, and the electric pressure of the
generator G so regulated by speed and armature windings that the current which
flows through the coil E of the generator G will, under all conditions, overpower
the current of coil E¹ to such an extent that a pre-determined excess of current
will flow through its coil E, sufficient for maintaining the desired volume of current
for the work circuit, no matter what the resistance of the work circuit may be, even.
to short circuiting the brushes of the work circuit generator. The construction
thus far described controls the volume of current in such a manner only as to
prevent the current of the work circuit from exceeding the volume of pre-determined
strength.
The next improvement refers to a scheme for preventing the current of the work
circuit from decreasing in volume below its pre-determined amount. This is
accomplished by the coil E which is connected in shunt from the brushes of the
generator G, the current which flows through this coil E always being proportional
to the resistance and volume of current of the work circnit. The coil E² is
differentially wound to the coil E of the generator G, therefore, when the ampère
turns of the two coils E and E³ equal each other, their generator G¹ will cease to
send current through the differential coil E', and the current which flows through
the coil E of the generator G will thereafter be unaffected by the coil E.
Therefore, when the generator G is supplying its maximum load, the generator G₁
is manifesting its minimum effects, and when the generator G is supplying its
minimum load, the generator G¹ is then doing its greatest work. The two machines,
therefore, always operate conjointly, but still in a manner inversely to each other.
But the proportional outputs of the two generators equal each other when the
generator G is doing one half of its capable work. It will be readily understood
that inasmuch as the generator G' is excited to primary action by the current of the
generator G, that any flow of current from G will instantaneously bring the
generator Ginto effective action, and the generator G' will therefore control
the generator G as effectually as the series coil of a compound constant potential
generator will effect its work circuit.
The functions of the coils E and E¹ of generator G, and the coil E' of generator G¹
can be reversed and still be effective. That is to say, the coil E2 could have the
direction of its current reversed so as to become supplemental to its fellow coil E.
The coil E of generator G could have its current reversed so as to become
differential, and the coil E' could be reversed so as to become the primary exciting
coil of the generator G. But such changes would impair the efficiency of the
machine, inasmuch as the current. of the work circuit would always be flowing
through the coil E of the generator G, thereby lowering the field of force. But
in the former case, as shown in Figure 1, the current which flows through the
coil E diminishes as the load in the work circuit increases. The proper
proportional windings embodied in the four-field magnet coils, shown in Figure 1,
can be determined when the machine is being constructed in the following
manner :-
Suppose the machine to be constructed suitable for one hundred are lamps, having
a current volume of ten amperes, and the coils E E connected together in linear
series, as shown in Figure 1. The coil E would first be wound suitable for
obtaining a field of force suitable for the total output of the one hundred lamps,
next the coil E' would be wound and connected in series with the coil E, but so as to
produce differential effects, and contain sufficient convolutions to reduce the voltage
of the work circuit for one lamp. The fall of potential would then be taken
between the terminals of the coil E¹. The generator G¹ would then be constructed

page_text: so that a ten ampère current, flowing through its coil E would produce a pressure
at its brushes equal to the fall of potential of the coil E¹, the speed of the
armature of the generator G' being adjusted to produce the desired voltage.
Next, the number of watts consumed in the coil E of generator G¹ would be
determined, and the coil E' would then be constructed so as to have a resistance
capable of letting through just enough current when the full load of the one
hundred lamps is on, to equal in watts, the number of watts consumed in the
coil E of the generator G. The two generators being thus constructed, will
control each other so as to maintain a current of constant volume in the work
circuit during all variations of load, and that, too, with an accuracy that can never
be equalled by mechanical devices, which operate by fluctuations alone in the
volume of current flowing through the work circuit.
This method for determining the proportional windings for the two machines is
based upon the construction shown in Figure 1, in which the coils E E of the two
generators are joined together in linear series, but if the two coils be joined in
multiple are, as illustrated in Figure 6, then a switch H' and a resistance I would
be interposed in the circuit of one of the coils for the purpose of either cutting in
or out the resistance H. In this way, the proportionate amounts of current
required to flow through the two coils E E to balance the generating capacity
of the two generators, can be easily adjusted. The essentials of this feature
of the scheme shown in Figure 6 may be carried out in any of the constructions
shown.
It has already been mentioned how constant current may be maintained in the
work circuit by reversing the function of the coils E E and E². Such a con-
struction is shown in Figure 2, except that the coil E of the generator G' is
supplied with current from its own armature. In this case, the regulating
generator becomes the primary exciter of the generator G. In this figure it is
also shown how the coil E2 may be applied to either generator, or both; coil E² of
generator G being shown connected in shunt with the work circuit by dotted lines,
marked M. A resistance H is also shown in Figure 2 arranged in series with the
coil E. This is quite essential in practice, as it affords an easy way for adjusting
the flow of current in the coil E to agree with the current flowing through coil E.
The coil E in Figure 2 may be dispensed with as shown by the dotted line N which
cuts the coil out by short circuiting its terminals through the conductor N. But
the machine will respond to variations of load in the work circuit more quickly if,
the differential coil E' be used.
The modification shown in Figure 3 has the two armature circuits rotatable in
the same field of force, otherwise, this construction is very similar to Figure 2.
In either case, the work circuit generator field magnets are wound with
coils EE and E2, and the coil E' may he cut out in the construction shown
in Figure 3, as mentioned in the case of Figure 2 indicated by the dotted line N.
In all of the constructions the resistance H is intended to be used, as shown in
Figure 2.
In Figure 4 a device is shown for automatically operating the brush holder
which is constructed and operated as follows:-
At either one or both ends of the brush arm I is secured thereto a solenoid.
core curved so as to suit its movable circle, and a solenoid helix is constructed
stationarily secured, and curved in a form to suit the core I¹. These helices are
wound with a coil of very high resistance, so as to be capable of standing the total
voltage of the work circuit. The terminals of the helices are connected to the
brushes of the generator G as is here indicated in Figure 4. But in practice they
may be connected in linear series with the shunt coil E².
KK are springs which are made strong enough to pull the brush holder to a
position suitable for the minimum load of the machine. These springs are therefore
counter-springs, pulling against the solenoid current. The current which flows
through the solenoid helices will vary directly proportional to the resistance of the
work circuit, therefore, the solenoid pull on the brush holder will increase, so as to

page_text: move the brushes in a position on the commutator suitable to all loads, of the
machine. Solenoids have been used heretofore to move the brush holder of a
constant current generator, but they have always been connected in series with the
work circuit, and therefore such a scheme is faulty inasmuch as in a constant
current system, there is too little variation in the volume of current to practically
operate any device requiring to move the brush holder. It is desired to call special
attention to the fact that the brush holder is not moved by the current of the work
circuit, but instead thereof the solenoid helices are arranged in multiple arc with
translating devices arranged in linear series with each other. This is an important
distinction. My correspondents do not wish to limit themselves to the particular
form of solenoid illustrated in Figure 4 for a modified form of solenoid or even an
electro magnet might be used.
The spirit of this feature of the invention lies in connecting the device in a short
circuit of a constant current system. There are also new features in the specific
device shown in Figure 4 in which the circuits of the solenoids and work circuit
are shown to terminate in the brushes, and each of said circuits is indicated by
arrow heads located on each circuit. The full arrows indicate the direction of
rotation of the armature suitable for the arrangement of the solenoids, as shown
in Figure 4. In a high potential constant current system, used for are lighting,
the resistance of the work circuit seldom changes less than five ohms at one time,
and such changes should be counter-balanced by a corresponding change in the
field magnetism, otherwise either the translating devices or generator will become
either defective in action, or else injured. Now, from the fact that changing the
magnetism of the field magnets will set up a counter electromotive force, due to
the discharge of the field magnet cores, therefore, provision should be made for the
escape of the induced current, otherwise the induced current will oppose the flow
of current through the fields, or else be induced into the armature windings, and
therefore cause a burn out. Metallic cylinders have been used heretofore for such
discharges. But they are sometimes expensive and troublesome to apply to
magnets and controlling devices, therefore the construction show. in Figure 5 is
devised. The scheme is carried out by winding a layer of insulated wire over the
core of the magnet, and then securing the ends of the wire to the core. In this
way, the core becomes part of the conductor for the How of current, which is
illustrated by the long arrow and the arrow heads in Figure 5. Two layers of
wire could be wound on the magnet core instead of one, and in such a case
the ends might be joined together, so as to form a closed circuit, the two ends
of the wire being at the same ends of the magnet. It is proposed to construct.
both the field magnets and solenoid helices in this way, so that they may respond.
instantaneously without being retarded by an opposing force.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, as cominunicated to.
me by my foreign correspondents, I declare that what I claim is :-
1. In a system of constant current generation and regulation, the combination of
two electrical generators with a work circuit, each of said generators having two
sets of field' magnet coils, one field coil of each generator and the work circuit
being connected in linear series with each other, one field coil of one generator
being arranged in multiple arc with the work circuit; and the remaining
field coil being supplied with current from the other generator, substantially as
described:
2. In a system of constant current' generation and regulation; the combination
of two electrical generators with a work circuit, each of said generators having
two sets of field coils, three of said sets of coils being supplied with current from
one of said generators and the remaining set of coils being supplied with current
from the other generator, the currents of electricity which flow through the two
sets of field coils of each generator, acting in a.differential manner to each other;
substantially as described!"

page_text: 3. In combination, a work circuit having its translating devices arranged in
linear series with each other, two electric generators, each being provided with two
sets of field coils, one of said sets of field coils being connected in multiple arc with
said work circuit only, means provided for causing said multiple arc field coil
to increase the potential of the work circuit current proportional as translating
devices increase the resistance of said work circuit, substantially as described.
4. In a system of constant current generation and regulation, the combination
with two generating armatures, of a work circuit having its translating devices
arranged in linear series with each other, and a shunt field magnet coil E'
traversed by a current of electricity, the volume of said current being caused
to increase when the resistance of the work, cir uit increases, substantially as
described.
5. In a system of constant current generation and regulation, the combination
with an electrical work circuit, of two sources of electricity, and a shunt circuit
having a coil E2 arranged therein, one of said sources of electricity supplying said
work circuit and also said shunt circuit, the current which flows through said work
circuit being caused to suitably lower the potential of its source of supply, and the
current of said second source, together with the current which flows through said
shunt circuit, being caused to suitably raise the potential of said first named source
of supply proportional to the resistance of said work circuit, substantially as
described.
6. In a system of constant current generation and regulation, the combination
with a work circuit having its translating devices arranged in linear series with
each other, of the generators G and G¹, each of said generators being provided
with field magnet coils, the generator G' supplying two sets of field coils, one of
said sets being wound upon its own magnet cores and the other set being wound
upon the magnet cores of the other generator, said two sets of field coils being
connected in multiple arc with each other, a third set of field magnet coils
being connected in multiple arc with the work circuit, a resistance H being
arranged therein, substantially as described.
7. In a system of clectrical generation and regulation, the combination of an
electric-generator provided with field magnets, and a discharge coil L coiled
upon said magnets, the ends of the coil being electrically joined to the core
upon which said coil is wound, having the core thus form a part of the
electrical circuit through which the discharge takes place, substantially as
described.
8. In a system of constant current generation and regulation, the combination
with two sets of field coils EE arranged in multiple arc with each other,
of a resistance H and switch H¹ arranged in the circuit of one of said field
coils E for balancing the current flowing through said coils, substantially as
described.
9. In a system of constant current generation and regulation, the combination
with a work-circuit having its translating devices arranged in linear series with
cach other, of two sources of electricity, a coil E2 connected in shunt with said
work circuit, and said coil having a resistance H arranged in electrical circuit
therewith, and means for cutting said resistance in or out of circuit, substantially
as and for the purposes set forth.
10. In a system of constant current generation and regulation, the combination
with a work circuit having its translating devices arranged in linear series with
each other, of two sources of electricity and two sets of field magnet coils, one set
of said coils being arranged in linear series with said work circuit, and the other
set of said coils being arranged in shunt with said work circuit, the current from
the two sources being used in combination to maintain a current of constant volume
in said work circuit, substantially as described.
11. In a system of constant current generation, the combination with an
electrical work circuit, of a shunt circuit, two sources of electricity, one of said
sources supplying said work circuit and also said shunt circuit, the current which

page_text: flows from the other source of supply, together with the current which flows
through said shunt circuit being caused to raise the potential of the current
supplying the work circuit proportional to the resistance of said work circuit,
while the current which flows through said work circuit is caused to lower the
potential of its source of supply suitably for maintaining. a current of constant
volume in said work circuit, substantially as described.
Dated this 12th day of April 1897.
WM. P. THOMPSON & Co.,
Agents.