Improvements in a Method and Apparatus for Generating and Distributing Electric Energy.
Year: 1898

page_text: Date of Application, 8th Nov., 1898-Accepted, 4th Feb., 1899
COMPLETE SPECIFICATION.
Improvements in a Method and Apparatus for Generating and
Distributing Electric Energy.
We, THE BRITISH THOMSON-HOUSTON COMPANY, LIMITED, of 83, Cannon Street,
in the City of London, Electrical Engineers, do hereby declare the nature of
this invention (which has been communicated to us from abroad by Charles M.
Green, residing at Lynn, in the County of Essex, State of Massachusetts, United
States of America, Electrical Engineer), and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
The present invention relates to an improvement in the generation and dis-
tribution of electric energy, the object of the invention being to so construct
the armature of a dynamo electric machine that two or more separate external
circuits can be taken therefrom in such manner that the electro motive force
supplied to each external circuit shall be generated in a particular set of the
armature coils, so that the difference in potential between any two points of
said external circuits or the machine, may be reduced to and maintained at any
desired amount, thus permitting the use with safety of dynamo electric machines
capable of generating currents of high electro-motive force.
A further object is to construct the armature of a dynamo electric machine,
in such manner that the coils shall be arranged in groups or sets so disposed
relatively to each other that the difference in potential between two coils of any
group or set shall be low, whereby thin or small insulation between the coils
of each group or set will suffice and result in reducing the weight and size of
the armature without detracting from the efficiency of the machine.
A further object is to provide means whereby a closed coil armature can be
made to generate electro motive force and distribute the same in subdivided
external circuits, each of which shall be in series with the others and with
subdivisions of the armature.
With these objects in view the invention consists in generating electro motive
force in two or more sets or groups of armature coils of a closed coil armature
and in distributing electro motive force so generated in separate external cir-
cuits having translating devices included therein, said external circuits being
connected between and included in series with the sets or groups of armature
coils.
The invention further consists in the combination with a dynamo electric
machine having a closed coil armature divided into two or more sets of coils or
bobbins and a commutator for each set of coils, some of the segments of each
commutator being connected with terminals of one set of coils and cross con-
nected with the balance of the segments of the respective commutators, of external
circuits corresponding in number with the number of sets of armature coils
said external circuits being connected between and included in series with the
respective sets of armature coils and with each other.
The invention further consists in certain novel features of construction and
037

page_text: combinations and arrangements of parts as hereinafter set forth and pointed
out in the claims.
In the accompanying drawings; Fig. 1 is a view illustrating the armature
and commutator connections; Figure 2 is an end view; Fig. 3 is a side eleva-
tion; Figure 4 is a diagrammatical view; Figure 5 is an elevation of an armature
showing the manner of insulation; Figure 6 is a view showing an armature
with the coils divided into three sets or groups.
In Figure 1 is shown a multipolar machine having four pole pieces A, A¹;
B, B, and a ring armature C having two sets or groups of closed coils. All
the coils or bobbins of each set or group are electrically connected together,
and the separate coils of each set are separated from each other by means of
thin insulating strips or discs a and the sets or groups of coils are separated
from each other by heavier insulating strips or discs b, all of which will be
hereinafter more fully explained.
With an armature having its coils divided into two sets or groups, two com-
mutators D, E, are employed one for each set or group. In Figure 1, the
line a represents a division line between the two sets of coils. The terminals
of all the coils on one side of this line (which constitute one set of coils), are
electrically connected with the adjacent segments of commutator D, and the
terminals of the coils of the other set are similarly connected with adjacent seg-
ments of commutator E. In other words, the terminals of the coils a¹, a², a³,
a a³ as a² and a8 are connected, successively, with the segments 1, 2, 3, 4, 5,
6, 7, 8, 9, of commutator D. The segments 1 and 9 are cross connected by
means of a conductor c. Segments 2, 3, 4, 5, 6, 7, and 8 are cross connected
with the remaining segments 10, 11, 12, 13, 14, 15, and 16, of commutator D,
by means of conductors d, e, f, g, h, i, j. The coils of the other set or group
are connected with segments of the commutator E and said segments are cross-
connected in exactly the same manner as above explained in connection with
commutator D and the set of coils connected therewith.
Commutator brushes F, F1 bear on the segments of commutator D and as
said segments are cross-connected and have electrically connection with one set
of armature coils, said brushes will, serve continuously, to collect current gen-
erated in said set of coils, during the operation of the machine. Commutator
brushes G, G¹, bear against the commutator E and collect current, in like manner,
generated in the other set of coils.
The commutator brushes are mounted on a suitable yoke 17 and the latter
is connected with an automatic regulator 18 which serves to shift the brushes
and automatically vary and regulate the output of electro-motive force to cor-
respond to the work or resistance that may be included in the external or work-
ing circuits.
A "wall regulator" 19 may also be employed to automatically
shunt some of the current around the regulator 18. It has not been considered
necessary to illustrate or describe in detail the construction or mode of operation
of said regulators 18, 19 because such devices are well known and any preferred
construction may be employed.
Instead of dividing the armature coils into two groups as above described and
shown in Figure 1, the coils may, for a six pole machine, be divided into three
groups and a corresponding number of commutators provided as shown in
Figure 6, no attempt being made in this figure however, to show the commutator
and its connections as the arrangement will be substantially the same as above
described. It is apparent also that for an eight pole machine, the armature
coils may be divided into four groups and a commutator provided for each
group.
External or working circuits corresponding in number with the number of sets
of coils in the armature of the machine, are employed and are so arranged as
to be connected between and included in series with the sets or groups of coils
or bobbins. In the diagrammatical view (Figure 4), the commutator brush F,

page_text: is shown connected with one end of the field magnet coils H and the other end
of the field magnet coils is connected, by a conductor 20 and through the regu-
lators 18, 19, with a contact post 21 of a switch board H. A shunt circuit 22
extends from the wall regulator 19 around the main regulator 18. The com-
mutator brush F is connected by a conductor 23, with a contact post 24 of the
switch board and another contact post 25 is connected by a wire 26 with the
commutator brush G. The brush G¹ is connected by a conductor 27 with a
contact post 28 of the switch board. The contact post 21 is connected by a
conductor 29 with a contact post 30. Another contact post 31 is connected,
by a conductor 32 with the commutator brush F. The contact posts of the
switch board are arranged in pairs and the posts of each pair are adapted to
be bridged by switch arms 33, 34, 35. The terminals of the external circuit (I)
are connected with the contact posts 24 25 of the switchboard and the terminals
of the external circuit (J) are connected with the contact posts 28, 30. From
this construction it is apparent that when all the switches are open, the two
external circuits will be in series with each other and with the two sets or groups
of armature coils of the dynamo electric machine. By means of the switch
arms 34, 35, the working circuits may be short circuited and by means of the
switch arms 33, the machine can be rendered inactive by short circuiting the
field magnet coils.
With all the switches open, the circuits may be traced as follows. Beginning
with the commutator brush F, through commutator D and the set of armature
coils connected therewith to brush F'; then by conductor 23 to post 24 of the
switchboard; then through external circuit I to post 25; then by conductor 26
to brush G; then through commutator E and the set of armature coils con-
nected therewith to commutator G'; then, by conductor 27 to post 28 of the
switch board; then through the external circuit J to contact post 30; then by
conductor 29 to post 21; then by conductor 20 through the regulators 18, 19,
and to one end of the field magnet coils and then from the other end of the
latter, to the commutator brush F. Thus all the electro motive force generated
in one set or group of armature coils will flow through the external circuit I
and the translating devices included therein, and all the electro motive force
generated in the other set or group of armature coils will flow through the
external circuit J, and the translating devices included in that circuit.
When it is desired to render the machine inactive the switch 33 will be
made to connect posts 21, 31, whereupon the field magnet coils will be short
circuited through the conductor 32. In the case of a six pole machine having
its armature coils divided into three groups, three external circuits will be
employed and in an eight pole machine having the armature coils divided into
four groups, four external circuits will be employed in each case, a corresponding
number of commutators will be used and placed in series with the external cir-
cuits in the manner above explained.
In each external circuit translating devices are included and, for the sake of
illustration, it may be assumed that in each circuit there are included 40 arc
lamps of 50 volts each, so that the load of each external circuit will nearly
balance the electro motive force generated in each of the sets or groups of coils
of the armature, the total capacity of the dynamo shown in Fig. 1 of the draw-
ing being assumed to be between 4,000 and 5,000 volts. The above conditions
are desirable in practice but they are not essential, since any one or more of
the circuits may be cut out or any number of lamps in either one of the circuits may
be included in which case the automatic regulator will operate to cut down
the total output of electro motive force generated by all the coils of the armature
to correspond to and operate the remaining lamps in circuit.
It is of course
understood that the figures above given are for the purpose of illustration
merely, although they closely approximate the conditions that exist in actual
practice and that in practice the inachine will have a capacity for generating
an amount of electro motive force, somewhat in excess of the amount expended

page_text: in operating the lamps or other translating devices in the external circuits.
It will be found that the difference of potential between any two points on the
machine or in the external circuits will but slightly exceed 2,000 volts, notwith-
standing that the machine (shown in Figure 1) is capable of generating a total
electro motive force of 4,000 volts or more.
By arranging the armature coils or bobbins in groups (as hereinbefore ex-
plained) so that each group will generate an electro motive force which will be
commutated and distributed in a separate external circuit, the difference of
potential between the coils will be low and consequently very light insulation a,
between the coils or bobbins will suffice and thus the weight and size of the
armature will be reduced to a minimum without detracting from the efficiency
of the machine.
Heavier insulation b, will, of course, be employed between the sets or groups
of coils.
Having now particularly described and ascertained the nature of our said
invention (as communicated to us from abroad) and in what manner the same
is to be performed, we declare that what we claim is:-
-
1-A system of electric generation and distribution consisting in generating
electro motive force in two or more sets or groups of armature coils of a closed
coil armature and in distributing the electro motive force so generated in separate
external circuits having translating devices included therein, said external
circuits being connected between and included in series with the sets or groups
of armature coils, substantially as set forth.
2-The combination with a dynamo electric machine having a closed coil
armature divided into two or more sets of coils or bobbins and a commutator for
each set of coils, some of the segments of each commutator being connected
with terminals of one set of coils and cross-connected with the balance of the
segments of the respective commutators, of external circuits corresponding in
number with the number of sets of armature coils, said external circuits being
connected between and included in series with the respective sets of armature
coils and with each other, substantially as set forth.
3-The combination in a dynamo electric machine, of an armature having its
coils or bobbins divided into two or more successive or adjoining sets, light
insulation between the individual coils or bobbins of each set and heavier insula-
tion between the sets of coils or bobbins, substantially as set forth.
4 The combination in a dynamo electric machine having a closed coil arma-
ture divided into two or more sets of coils or bobbins and a commutator for each
set of coils, of lighting or working circuits corresponding in number with the
number of sets of armature coils, said working circuits being connected between
and included in series with the respective sets of armature coils and with each
other, and an automatic regulator for varying the electro motive force of the
current generated to correspond with work included in said working circuits,
substantially as set forth.
THE BRITISH THOMSON-HOUSTON CO., LTD.,
A. R. MONKS,
W. MARTINDALE,
ALFRED CLEMENTS,
Directors.
Assistant Secretary.