An Improved Method of and Apparatus for Generating and Utilizing Electricity.
Year: 1898

page_text: [Communicated from abroad by JOSEPH JAMES FEELY, of 95, Milk Street, Boston,
Massachusetts, United States of America, Counsellor at Law.]
An Improved Method of and Apparatus for Generating and Utilizing
Electricity.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent Agents,
45, Southampton Buildings, in the County of Middlesex, 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 method and apparatus for generating and utilizing
electricity, and capable of operation by a source of power which is liable to sudden
and wide fluctuations or variations, such as wind power or the power which may
be taken from the rotating axle of a street or railway car.
For some of the uses of electricity, and especially for electric lighting, a con-
stant electric pressure on the mains must be maintained, and as the said pressure
or voltage when produced by the common forms of dynamo varies according to
the speed produced at its armature by the driving power, the ordinary methods
of electric generation cannot be employed for such purposes when the source of
power is liable to vary or fluctuate to a substantial amount. The problem there-
fore which this invention purports to solve was to successfully utilize a variable
or fluctuating source of power to generate electricity at a practically constant
pressure or voltage.
I will first describe my preferred form of apparatus for carrying out my inven-
tion. Such an apparatus is shown diagrammatically in the accompanying
drawings.
In the said drawings, A represents a dynamo having the usual field magnets 2 2
and armature 3, which parts may be of any preferred design as they are not
peculiar to my machine. The pole pieces of the field magnets are connected by an
iron core 4, forming a magnetic shunt around the armature. 5 5 are the field
coils connected in shunt with the armature and 6 is a coil in series with the field
coils and wound on the iron core 4. All these coils are of high resistance and
consist of a considerable number of turns, as is usual in the case of shunt wound
dynamos. The sizes of the coils 5 and 6 are such that, neglecting any effects due
to the action of the coil 7 hereinafter described, the intensity of magnetization pro-
duced in the magnetic shunt 4 by a given current will be the same as that produced
in the field magnets 2 2, and these coils are so wound and connected that the
magnetic lines of force produced by all of them will be driven through the
armature 3 in the same direction, as indicated in the drawings by the full-line
arrows.

page_text: 7 is a coil of relatively heavy wire and few turns, in series with the external
circuit, and wound on the iron core 4 in such manner that the magnetic lines of
force produced by a current passing through said coil will oppose and cut down
those produced by the coil 6.
B is a storage battery into which the current generated by the dynamo A is
passed, and which with its connections to the dynamo, including the coil 7, may
form the entire external or working circuit of the system, although as will
presently appear a shunt circuit may be led off from said battery and be used
to supply lamps or to perform other useful work. This battery B may consist
of cells of any approved type.
C is a switch, preferably made automatic in its action by being so constructed
and connected in the system that when the dynamo is running at speeds too
low to produce a voltage which will be useful in the system the working circuit
will be kept open thereby, but will be closed as soon as the voltage reaches a pre-
determined point, and will remain closed only so long as the voltage is at or above
that point. The specific construction of this switch is not shown or described
herein, as its details do not form a part of this invention. Any suitable switch
which is capable of performing the necessary functions may be used and in some
cases my invention does not require the use of an automatic switch, as will be
hereinafter shown.
In constructing and setting up my system, I usually proceed as follows. Having
determined what the working voltage of my dynamo is to be, I assume a minimum
speed (the best practical rate of which, in the case of any particular variable
power, may be determined by experiment), and from these data I calculate the size
of my armature and field magnets, and the coils therefor, in the usual manner,
as these parts do not differ from the corresponding parts in an ordinary shunt
wound dynamo. I then determine, by calculation or experiment, the highest
speed which my source of power is to give to the armature when the output of
the dynamo is at its maximum, and I construct the iron core 4 of such cross
section that the sum of the cross sections of said core and of the field magnets
will be to the difference of said cross sections (the cross section of the core always
being the less of the two) in the same ratio that the maximum speed of the
armature is to its minimum speed, as determined in the manner above described.
Having thus determined the size of the core 4, the coil 6 is so proportioned, as
above stated, that it will tend to magnetize said core to the same intensity that
the field coils magnetize the field magnets 2 2. Finally, the coil 7 is given such
size that when the dynamo is running at its highest speed as above determined
the effect of the current through the coil 7 will just neutralize the effect of the
coil 6 with respect to the magnetization of the core 4. The considerations which
determine the strength of this current through the coil 7 will clearly appear from
the subjoined description of the operation of the system. The proportions just
given of the several parts of my dynamo are those which I have found most
efficient in practice, but they may be considerably varied without departing from
my invention.
The storage battery B is composed of sufficient elements to yield the voltage
which has been determined upon as the working voltage of the system, and the
switch C, when used, is constructed to operate at that voltage.
As thus constructed, the operation of my system is as follows. Whenever the
external circuit is closed through the switch C, the storage battery B opposes to
the voltage of the dynamo a counter electromotive force which is steady and
practically constant. Whenever the voltage of the dynamo tends to rise above
that of the battery, the current thus generated through the battery passes also
through the coil 7 and instantly operates to cut down some of the magnetic lines
of force produced by the coil 6, so that the magnetic flux through the armature is
lessened not only by the number of lines thus neutralized but also by an additional
number, produced by the field coils, which leak or are shunted around the arma-
ture through the core 4, its intensity of magnetization having been diminished

page_text: by the action of the coil 7. This diminution of the flux through the armature
reduces the voltage of the dynamo nearly to that of the battery, the excess being
just sufficient to maintain such a current through the coil 7 as is necessary to
reduce the flux through the armature and establish the requisite balance between
the speed and the voltage of the dynamo.
Thus strictly speaking my dynamo does not act to keep its own voltage con-
stant, but does keep within very narrow limits the difference between its voltage
and that of the storage battery, and by keeping the external resistance very small,
as is the resistance of a storage battery, this voltage difference will produce a
current which will vary sufficiently with varying speeds to keep said voltage
difference within practical limits. The storage battery acts as a reservoir for
this varying current and converts into stored energy the excess over what is being
used by the rest of the system. When the supply of power falls too low to generate
the necessary voltage, the switch C opens the external circuit, in which case the
voltage of the dynamo, for all lower speeds, varies with the speed, as the regulating
device is for the time being inoperative.
No depolarization or demagnetization of the field coils of my dynamo can
possibly occur, for at the highest calculated speed of the dynamo the coil 7 does
no more than completely neutralize the coil 6, and its action cannot reduce the
magnetism of the field magnets at all, even if the speed runs still higher than
was designed for, because even if the magnetic effect of the coil 7 overpowers that
of the coil 6 and generates a magnetic flux in the opposite direction, this will
not affect the polarity of the field, but will tend to draw the flux produced by
the field coils through the shunt 4, by giving the latter a pronounced polarity,
My invention thus overcomes a defect found in certain previous systems devised
for the same purpose, which were liable to be depolarized or injuriously demag-
netized by their own action.
A shunt circuit 8 may be connected to the terminals of the battery B, which
circuit by virtue of the automatic regulation above described will have a practi-
cally constant difference of potential at its terminals, and thus a number of incan-
descent lamps may be kept burning steadily in such circuit even while the dynamo
is sending a variable current through the battery, as the lamps will consume as
much of the current as they require, while the rest will be taken up by the
battery. In like manner such a shunt circuit is capable of doing other useful
work.
From the foregoing description it will be seen that the method of operation
embodied in my invention is briefly as follows. I design a dynamo which at a
given minimum speed shall generate a given voltage, to which voltage I oppose
an independent voltage which is steady and of nearly equal amount, and I
automatically keep the difference between these two voltages within relatively
narrow limits by means of a varying magnetic leakage around the armature of
the dynamo produced by impressing this small, varying difference of voltage on
a circuit of low resistance. Finally, I provide for the utilization of the current
thus produced. If my variable source of power is liable to fall so low at times
that it will not generate a sufficient working voltage, I then employ a switch
whereby the working circuit will be broken when no useful effect is being pro-
duced, but if the source of power is always adequate to produce some useful result,
then no switch C need be used.
The switch C should be so constructed that it will operate to close the external
circuit when the voltage generated by the dynamo just equals the counter electro-
motive force of the storage battery, so that the current sent through the said
battery will start from zero and increase from that point as the speed of the
armature increases.
The field coils of my dynamo and the coil 6, being of high, resistance, receive
a current which varies but little after the dynamo has begun to generate its
regulated voltage. These coils may therefore be supplied with current from some
source which is external to the dynamo, such as a storage battery.

page_text: The voltage of the storage battery of course varies somewhat according to the
extent to which it is charged. My system however, while it is able to regulate
itself at high wind speeds, is also capable of being operated by wind speeds as low
as six to eight miles per hour, which are among the most frequent of all wind
speeds, so that I am able to use a small storage battery and to charge it at
frequent intervals and thus keep its voltage from varying to any great extent.
I therefore consider my invention to be peculiarly adapted for the transforming
of wind power, but it may be made useful in connection with any other variable
and sufficient source of power, and will successfully transform the same whether
its variations be great or small, regular or irregular, sudden or gradual, inter-
mittent or continuous.
By disconnecting the source of power and sending a current through my
dynamo, it may be run as a motor, and will then tend to preserve a constant speed.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, as communicated to me by
my foreign correspondent I declare that what I claim is:-
1. The herein described method of generating by a dynamo electricity of practi-
cally constant pressure from a source of variable motion which consists in opposing
to the generated voltage an independent, steady voltage, and automatically keeping
the difference between the two voltages within narrow limits by impressing it on
a circuit of low resistance and causing the resulting current to vary the magnetic
conductivity of a magnetic shunt around the armature of the dynamo, for the
purpose set forth.
2. In a system for generating electricity, a dynamo adapted to be driven at
varying speeds and provided with means for keeping its voltage practically con-
stant, comprising a magnetic shunt around its armature and means for varying
the magnetic conductivity of said shunt and thereby automatically regulating the
magnetic flux through the armature, for the purpose set forth.
3. In a system for generating electricity, a dynamo adapted to be driven at
varying speeds and provided with means for keeping its voltage practically
constant, said means comprising a magnetic shunt around its armature, a high
resistance coil on said shunt, and a low resistance coil on said shunt in series
with a low external resistance, said coils producing opposite polarities, substan-
tially as described.
4. In a system for generating electricity, the combination with a storage
battery of a dynamo adapted to be driven at varying speeds, said dynamo having
a magnetic shunt around its armature and means for varying the magnetic con-
ductivity of said shunt and thereby automatically regulating the magnetic flux
through the armature, for the purpose set forth.
5. In a system for generating electricity, in combination with a storage battery,
a dynamo having a magnetic shunt around its armature, a high resistance coil
on said shunt adapted to be fed with a practically constant current, and a low
resistance coil on said shunt connected in series with the external circuit and
producing an opposite polarity to that of the first mentioned coil, for the purpose
set forth.
6. In a system for generating electricity, in combination, a dynamo adapted to
be driven at varying speeds, and having a magnetic shunt around its armature
and means for varying the magnetic conductivity of said shunt and thereby
automatically regulating the magnetic flux through the armature, a storage
battery, and an automatic switch arranged to close and open the external circuit,
substantially as described.
7. In a system for generating electricity, the combination with a storage battery
of a dynamo adapted to be driven at varying speeds, said dynamo having a mag-
netic shunt around its armature, a high resistance coil on said shunt, and a low
resistance coil on said shunt connected in series with the external circuit and
producing an opposite polarity to that of the first mentioned coil, and an automatic
switch arranged to close and open the external circuit, substantially as described.

page_text: 8. In a system for utilizing variable power for generating electricity at a
practically constant pressure, the combination with a storage battery of a dynamo
the voltage of which is automatically regulated as herein described by means of
an electro-magnetic shunt around its armature, whereby the voltage of the storage
battery may be kept practically constant, substantially as described.
Dated this 12th day of July 1898.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.