Year: 1886

page_text: Date of Application, 12th July, 1886.
Complete Left, 12th Apr., 1887.
Complete Accepted, 13th May, 1887.
WILLIAM MAXWELL 34 Claybrook Road Fulham S.W. Engineer, I do hereby declare
the nature of this invention to be as follows:-
My invention relates chiefly to the winding of the armature and the field-magnets
of dynamo-electric machines.
I wind the armature with two or more sizes or guages of wire or conductors
electrically insulated from each other so as to form two or more separate or
independent electrical circuits.
The current generated in one of these circuits may be used to excite the field-
magnets either in whole or in part.
The current generated in another of these circuits may be employed either wholly
or partially in the outer circuit or circuits.
When I wind the armature with two electrical conductors or circuits-relatively of
high and of low resistance-I may excite the field-magnets wholly by the current
derived from the high resistance circuit, or I may use a shunt from the low resistance
circuit in conjunction therewith, or I may pass the whole or a part of the current
from the low resistance circuit through coils wound around the field-magnets in series
with the outer circuit, and so cause it to act in conjunction with the current from the
high resistance circuit in order to control or strengthen the magnetic field.
In applying my invention to dynamoes of the continuous current type the armature
may be first wound with the fine conductor and afterwards with the coarse, or in the
reverse order, or the conductors may be wound on together or in successive or alternate
layers sections or coils.
It is obvious that the armature may be similarly wound with more than two
conductors.
Commutators or collectors of any suitable construction may be provided for the
separate currents.
Instead of the thick coils ordinarily used in the series winding of field-magnets
I may use coils of fine wire connected in parallel or in parallel-series for the low

page_text: resistance exciting circuit and I may use similar coils connected in series or series-
parallel for the high resistance exciting circuit.
The series and parallel coils may be arranged either on separate arms of the field
magnets, or together in any suitable order or manner, and any suitable form of
commutator may be used to effect the change of any number of the coils from series
to parallel, or the reverse.
When my invention is applied to dynamoes of the alternating current type each
bobbin of the armature may be wound in the manner hereinbefore described and the
coils intended for use in the exciting circuit may be joined either in series or in
parallel to a commutator of any suitable construction, or separate bobbins may be
used for the exciting circuit.
The field magnets may be wound with coils connected in series or parallel or in
parallel-series.
These improvements may also be applied in the construction of electro-motors.

page_text: I, WILLIAM MAXWELL. of 34 Claybrook Road, Fulham, S.W. 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 winding and connecting of the coils of the armatures
and field magnets of dynamo-electric machines, in such a manner that, without
excessive speed, a strong and constant magnetic field can be produced, and that self
regulation can be effected.
I wind the armature with two sets of wires or conductors, electrically insulated
from each other, so as to form two separate independent electric circuits, or parts
thereof, and I provide a commutator or collector of any known kind for each of these
circuits.
The two sets of conductors, which, generally, are of high and low resistance
respectively, are wound on the armature side by side, or in layers one above the other,
or they may be wound in interspaced coils or sections, all those of the one set being
connected to one of the collectors or commutators, and all those of the other set being
connected to the other.
In winding the field magnets I employ two sets of conductors, preferably of high
and low resistance respectively, and I connect one set of the armature conductors to
the high resistance coils of the magnets, so as to produce the magnetic field by the
current generated in these conductors. The field thus produced is strengthened or
controlled by the current from the other set of armature conductors which passes
through the second set of coils of the field-magnets and also through the outer circuit.
Instead of thus controlling the magnetic field, I sometimes use high resistance
wires for both sets of the field magnet coils, and excite the second set by a current
derived from the low resistance conductor of the armature, as in "shunt winding."
As the strength of the shunt current is greater or less according as that of the main
current is less or greater, I connect in this case the shunt coils of the field magnets
so that they tend to produce polarity opposite to that produced by the current which
excites them. The field is thus controlled by weakening it, when the current in the
outer circuit is lessened, and by allowing it to recover strength when the current in
the outer circuit is increased.
When the dynamo machine is required to have a magnetic field of constant strength,
I wind the field magnets with one set of high resistance coils and use exclusively the
current from the armature high resistance conductors to produce the field, the current
from the low resistance conductors of the armature serving the outer circuit. This
arrangement may, however, be reversed, that is to say, the current from the low
resistance conductors of the armature night be used to excite the field magnets, while
the current from the high resistance conductors might be employed in the outer
circuit, or, if desired, for controlling the magnetic field.

page_text: Sometimes, electro-magnets are wound with a number of coils, which can be
connected together in series or parallel in any desired order.
The field magnets of a dynamo electric machine may be thus wound and, when a
constant magnetic field is required, all these coils may be connected in series with the
high resistance coils of the armature.
For self regulating machines, a part of the coils may be connected in series to form
the prime exciting circuit of the field, and a part parallel to form a low resistance
circuit, which can be connected in series with the outer circuit. Or, instead of
joining a part of the electro magnet coils parallel, they may be joined in series
forming an independent circuit for controlling the field by a shunt" from the main
circuit as previously described. Suitable switches or commutators may be used to
change any number of the coils from series to parallel, or the reverse.
"
Although I have described my invention as applied to dynamo-electric machines
generating electricity, obviously a like construction may be used in electro-motors, in
which case the electric current supplied may be caused to circulate through one of the
armature and field magnet circuits, the other being open, or currents may be used in
both circuits or, if required, the second armature circuit may be arranged to act as a
generator. With such an arrangement the machine may be used as a combined
motor and generator or transformer. The motor current may pass through one of
the armature and field magnet circuits and thus a current would be generated in the
other armature circuit. This current, according to the nature of the winding, might
be different from the motor current in pressure or quantity, and might be used to
govern, strengthen or control the magnetic field by a shunt or series winding.
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. In the construction of dynamo-electric machines, winding the armature with
two conductors or two sets of conductors, the one applied to excite the field magnets
and the other to supply the external circuit, substantially as and for the purpose
herein set forth.
2. In the construction of self regulating dynamo-electric machines, winding the
armature with two conductors or two sets of conductors, the one applied to produce
the magnetic field and the other to supply the external circuit, and also to regulate or
control the magnetic field of the machine, substantially as herein described.
3. In the construction of dynamo-electric machines, winding the armature and also
the field magnets with two sets of conductors, substantially as and for the purposes
herein set forth.