Improvements relating to the Distribution of Electric Currents.
Year: 1899

page_text: Improvements relating to the Distribution of Electric Currents.
"
I, BENJAMIN GARVER LAMME, of 230, Stratford Avenue, Pittsburgh, in the
County of Allegheny and State of Pennsylvania, United States of North America,
Electrical Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to the regulation of electromotive force, and is especially
adapted for regulating electromotive force supplied by a generator driven at a
variable speed, or which otherwise supplies a variable electromotive force.
In operating translating devices in parallel on what is known the' constant
potential system, it is of course necessary for the efficient working of the same
that the electromotive force supplied by the generator should be maintained as con-
stant as possible, or the electromotive force may increase slightly with the load,
and in order to obtain such a result the generator has in general been run at'a sub-
stantially constant speed. Whilst such constancy may be readily secured with
some kinds of prime mover, yet when water wheels for example are used, and in
some other cases, it is almost impossible of attainment.
According to my present invention, I regulate the electromotive force of the
generator by automatically adjusting its field magnet excitation in accordance
with changes in speed or in accordance with such other variations as tend to
change the electromotive force.
f.
In the accompanying drawing, I have shewn a, diagram of machines
and circuits in which 1 is a generator rotated by a prime mover
not indicated in the diagram, said generator having a shunt field magnet
winding 3 and a series field-magnet winding 2 and supplying translating devices 7
and 8 through parallel mains 5 and 6. A variable resistance 4 is included in
the shunt circuit of the generator in order that the electromotive force may be
adjusted to suit the conditions under which it is desired to operate the system.
It will be understood, however, that when such resistance has been once adjusted
it will not ordinarily be necessary to vary the same afterwards.
For the purpose of regulating the electromotive force supplied by the gene-
rator 1, I provide a motor 9 having a shunt wound field-magnet 10 connected
across the mains. Said motor may, however, have a' series wound compound
wound. or separately excited field-magnet, instead of a shunt field-magnet, if
desired. Whatever the type of motor employed the relation between the field-

page_text: magnet core and its winding should be such that the former is maintained at the
point of magnetic saturation or approximately at that point at all times during
the operation of the system. By this means any change in the electromotive
force of the mains 5 and 6 will immediately cause a corresponding variation in
the speed of the motor 9. In case the machine 1 is an alternating current gene-
rator, a series field-magnet winding for the motor 9 would probably be most
desirable, but for a direct current system a shunt or a separately excited winding
would be more desirable for this motor.
The rotary portion of the motor is mechanically connected with the armature
f a generator 11 which is provided with a shunt wound field-maguet 12 having
an adjustable resistance 13 in circuit therewith; this resistance being adjusted to
suit the conditions of operation, and not otherwise varied, in a similar manner
to the resistance 4 herein before mentioned. The relation between the magnet
coil and its core is such that under normal conditions the field-magnet is much
below the point of magnetic saturation. I thereby ensure that any alteration
of the speed of the generator 11 will very quickly cause a change in its field-
magnet magnetisation, and consequently vary the electromotive force given out
by the machine. The armature of the generator 11 is connected in series with the
shunt winding 3 of the motor 1, and the motor 9 is so connected and driven
that the electromotive force impressed by, the generator 11 upon the shunt
circuit of the machine 1 is in opposition to that impressed upon such circuit
by the last named generator. Since the line electromotive force is adjusted by
adjusting the excitation of the field-magnet of generator 1, this adjustment of
excitation or magnetisation may be effected by providing a separate opposition
winding for the opposing electromotive force supplied by the generator 11, instead
of opposing the normal electromotive force directly in the same winding as will
be readily understood.
The operation of the system is as follows:-
If tlie electromotive force between the mains 5, 6, changes from any cause,
the speed of the motor 9 will immediately be altered as hereinabove mentioned.
The speed of the generator 11 which is driven by the motor 9 will also be altered,
and thereby vary the electromotive force supplied by the armature of said gene-
rator. This electromotive force which acts to reduce the magnetization of the
field-magnet of the generator 1 will bear such a relation to the magnetizing
electromotive force of said generator that the electromotive force given out by
the armature thereof will be maintained approximately constant.
The combination of motor 9 and compensating generator 11 may obviously be
replaced by their equivalent, namely, a motor generator or rotary transformer of
any suitable type.
The regulation obtained by the use of my invention although probably not
so close as to absolutely eliminate all fluctuations, will be sufficient for the
successful operation of ordinary translating devices.
W. P. THOMPSON & Co.,
322, High Holborn, London, W.C., Patent Agents for the Applicant.
Improvements relating to the Distribution of Electric Currents.
I, BENJAMIN GARVER LAMME, of 230, Stratford Avenue, Pittsburgh, in the
County of Allegheny and State of Pennsylvania, United States of North America,
Electrical 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:-
My invention relates to the regulation of electromotive force, and is especially

page_text: adapted for regulating. electromotive force supplied by a generator driven at a
variable speed, or which otherwise supplies a variable electromotive force.
In operating translating devices in parallel on what is known the constant
potential system, it is of course necessary for the efficient working of the same
that the electromotive force supplied by the generator should be maintained as con-
stant as possible, or the electromotive force may increase slightly with the load,
and in order to obtain such a result the generator has in general been run at a sub-
stantially constant speed. Whilst such constancy may be readily secured with
some kinds of prime mover, yet when water wheels for example are used, and in
some other cases, it is almost impossible of attainment.
According to my present invention I regulate the electromotive force of the
generator by automatically adjusting its field magnet excitation in accordance
with changes in speed or in accordance with such other variations as tend to
change the electromotive force.
In the drawings accompanying my Provisional Specification I have shewn a
diagram of machine and circuits in which 1 is a generator rotated by a prime
moved not indicated in the diagram, said generator having a shunt field magnet
winding 3 and a series field-magnet winding 2 and supplying translating devices 7
and 8 through parallel mains 5 and 6. A variable resistance 4 is included in
the shunt circuit of the generator in order that the electromotive force may be
adjusted to suit the conditions under which it is desired to operate the system.
It will be understood, however, that when such resistance has been once adjusted
it will not ordinarily be necessary to vary the same afterwards.
For the purpose of regulating the electromotive force supplied by the gene-
rator 1, I provide a motor 9 having a shunt wound field-magnet 10 connected
across the mains. Said motor may, however, have a series wound compound
wound. or separately excited field-magnet, instead of a shunt field-magnet, if
desired. Whatever the type of motor employed the relation between the field-
magnet core and its winding should be such that the former is maintained at the
point of magnetic saturation or approximately at that point at all times during
the operation of the system. By this means any change in the electromotive
force of the mains 5 and 6 will immediately cause a corresponding variation in
the speed of the motor 9. In case the machine 1 is an alternating current gene-
rator, a series field-magnet winding for the motor 9 would probably be most
desirable, but for a direct current system a shunt or a separately excited winding
would be more desirable for this motor.
The rotary portion of the motor is mechanically connected with the armature
of a generator 11 which is provided with a shunt wound field-magnet 12 having
an adjustable resistance 13 in circuit therewith; this resistance being adjusted to
suit the conditions of operation, and not otherwise varied, in a similar manner
to the resistance 4 hereinbefore mentioned. The relation between the magnet
coil and its core is such that under normal conditions the field-magnet is much
below the point of magnetic saturation. I thereby ensure that any alteration
of the speed of the generator 11 will very quickly cause a change in its field-
magnet magnetisation, and consequently vary the electromotive force given out
by the machine. The armature of the generator 11 is connected in series with the
shunt winding 3 of the generator 1, and the motor 9 is so connected and driven
that the electromotive force impressed by the generator 11 upon the shunt
circuit of the machine 1 is in opposition to that impressed upon such circuit
by the last named generator. Since the line electromotive force is adjusted by
adjusting the excitation of the field-magnet of generator 1, this adjustment of the
excitation or magnetisation may be effected by providing a separate opposition
winding for the opposing electromotive force supplied by the generator 11,.
instead of opposing the normal electromotive force directly in the same winding,
as will be readily understood.
The operation of the system is as follows:-
If the electromotive force between the mains 5, 6, changes from any cause,

page_text: the speed of the motor 9 will immediately be altered; as hereinabove mentioned.
The speed of the generator 11 which is driven by the motor 9. will also be altered,
and thereby vary the electromotive force supplied by the armature of said gene-
rator. This electromotive force. which acts to reduce the magnetisation of the
field-magnet of the generator 1, will bear such a relation to the megnetising
electromotive force of said generator that the electromotive force given out by
the armature thereof will be maintained approximately .constant.
The combination of motor 9 and compensating generator 11' may obviously be
replaced by their equivalent, namely, a motor generator or rotary transformer of
any suitable type.
The regulation obtained by the use of my invention although probably not
so close as to absolutely eliminate all fluctuations, will be sufficient for the
successful operation of the ordinary translating devices.
が
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed;, I declare that what
I claim is:-
:-
1. The combination with a dynamo supplying current to a distributing system,
of a direct current generator for varying the excitation of. the dynamo said direct
current generator being driven by an electric motor included in the distributing
system, substantially as described.
J.
2. The modification of the invention in which the electric motor and direct
current generator driven thereby are replaced by a rotary transformer substan-
tially as described.
3. A system of electrical distribution arranged and operating substantially as
described with reference to the accompanying drawing..
Dated this 3rd day of February 1900.
W. P. THOMPSON & Co.,
3
Of London, Liverpool, Manchester, and Birmingham
W. P. THOMPSON & Co.,
Of London, Liverpool, Manchester, and Birmingham