Year: 1886

page_text: Date of Application, 7th Oct., 1886
Complete Left, 7th July, 1887.
Complete Accepted, 7th Oct., 1887
SYDNEY FERRIS WALKER 195 Severn Road Cardiff Electrical Engineer do hereby
declare the nature of this invention to be as follows :-
My invention relates to improvements in the construction of the Armatures or
revolving portions of apparatus in which Electric currents are generated by the
passage of Electrical conductors through a magnetic Field and also in those in which
the passage of an Electric current through Electrical Conductors which lie in a mag-
netic field furnishes mechanical motive power.
In place of constructing my Armatures, in both cases (generators & motors) as at
present; of a ring of iron wire or of iron rings and coiling copper wires round the
core transversely to the plane of the lamination of the core, I build the armature itself
entirely of iron in the form of sectors of a cylinder. Each sector will be insulated
from its neighbour on either side of it by suitable insulating material, but will be con-
nected electrically at one end to its neighbour on one side, and at the other end to its
neighbour on the other side so that the whole of the sectors form one continuous con-
ductor as in the copper wires of the Gramme Ring. The usual Commutator may be
used, taking connection from certain of the sectors equally spaced round the Armature
or I may have a Sector in the Commutator for every Sector in the ring; or I may
cause the collector to take its current direct from the Armature without the interven-
tion of any Commutator; the Armature itself being its own Commutator. The
Armature when built up in the manner described or by equivalent methods will be
mounted on a spindle in the usual way but insulated from it by suitable means such as
one of the plans that have long been adopted for holding the revolving Commutators
upon Gramme & other Dynamo Machines; or I may have in connection therewith
a boss keyed on the spindle and radial arms to carry the sectors in a positive manner
but insulated therefrom. It is of course important that the mass of the iron sectors
should bear such proportion to the copper wire they displace as the difference in the
specific resistance of iron and copper would dictate.
Dated this Sixth day of October 1886

page_text: Improvements in Dynamo-electric Machinery.
SYDNEY FERRIS WALKER Electrical Engineer 195 Severn Road Cardiff Glamorgan
do hereby declare the nature of my invention for IMPROVEMENTS IN DYNAMO ELECTRIC
MACHINERY 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 revolving armatures of machines that are used for con-
verting mechanical energy into electrical currents, and for converting electrical
energy in the form of electrical currents into mechanical energy, by means of the
passage of an electrical conductor thro' a magnetic field.
In the armatures of these machines as hitherto constructed, a length of insulated
copper wire has been wound longitudinally upon an iron core; the copper wire being
divided into sections, and there being a certain number of turns according to the
electro-motive force required. In this form of armature the iron core itself generates
currents within itself which cannot be utilised, and which also tend to heat the cores
and the copper wires around them.
In my Invention, which is applicable to every known form of armature, I construct
the armature of iron, with the exception of the insulating material, and that used for
connections between the sections.
The construction of an armature according to my invention will be understood from
the following
Take a cylinder of iron whose radial depth & length are equal to those of the whole
armature under the old construction, including the copper wire.
Mark off divisions upon the periphery of this iron cylinder equal in number to the
turns of wire required to give the required electro-motive force, allowing for the
altered construction.. Saw thro' the cylinder at each of these divisions, with a saw
of sufficient thickness to leave room between the sewn segments for the insulating
material to be used. Having sawn the cylinder into the required number of segments,
build it up again, into its original form, filling up the saw cuts with Asbestos, Mica,
or any other suitable insulating material.
Now connect each segment with its neighbour on each side as follows:-
One end of each segment is to be connected to the opposite end of the segment on
one side of it; and it's other end to the near end of the segment on the other side.
Thus if we are looking at one end face of the arinature, and at three adjacent segments
respectively numbered 1, 2 & 3; the near end of 1, will be connected with the far end
of 2, the near end of 2 with the far end of 3, and so on all the way round; the whole
of the segments and their connecting wires forming one continuous circuit, as in other
armatures.
Or, a number of the segments may be connected together, and to a special form of
commutator, forming the circuit thro' the commutator, as in the armature known as
the "Brush.
The connecting wires may be conveniently of insulated copper, and may be arranged
as most convenient.

page_text: One plan is to have lugs on the iron segments, projecting inwards, and to connect
the copper wires to them.
In practice it would probably be more convenient to calculate the section of the iron
required, and have it rolled to that section, cut off in lengths and built up into a
cylinder with insulating material as before.
The connection of the armature to the spindle may be in any convenient mechanical
way that will give sufficient strength, and preserve the insulation of the sections from
each other and from the spindle itself.
The following plans may be adopted amongst others.
Each end face of the armature may be fitted with a metal disc, keyed on the spindle
& having a flange to go over the ends of the segments; leaving also sufficient space
inside the flange to allow of a disc of insulating material of similar form being placed
so as to come between it and the armature, when so fitted, the two discs are forced on
the armature, and screwed up tight by means of a flange on one side & locking nuts
on the other.
Another plan is similar to that adopted in many forms of commutators attached to
armatures.
An annular groove is turned in each end face of the armature. In this groove is
fitted a ring of insulating material also having a groove turned in it; and in this
groove in the ring of insulating material is fitted a flanged brass ring keyed on the
spindle. These rings are screwed up as before, with locking nuts.
This last plan may be strengthened by forming key ways in the segments, as pro-
jections from the annular grooves. A third plan is, to provide arms on the spindle;
either forming part of it, or in the form of a spider and boss, keyed on the spindle;
and allowing these arms to project between certain of the segments, but insulated from
them. In this case, insulated rings will also be required to keep the armature in place
longitudinally.
For the purpose of collecting the currents generated by the armature, I may either
allow the collecting brushes to rest on the segments themselves, making the armature
sufficiently long for that purpose; or I may provide a commutator attached mechani-
cally to the same spindle, as in the gramme and other dynamo machines.
If I provide a separate commutator, it may consist of an equal or a less number of
segments than are contained in the armature itself; and I may make the connections
between the segments of the armature and commutator either by providing lugs for
the purpose, or by connecting copper wires to the armature segments and to the com-
mutator segments, or in any other convenient manner. I may also make the iron
segments of the form shown in Figures 4 & 5 in those cases where the currents
formed within the segments themselves are of sufficient consequence to effect either
the efficiency of the machine, or the working cost of the installation in which the
machine is used.
I do not bind myself to these forms but may use any convenient form that will
preclude the formation of useless currents.
In the accompanying drawings;
Fig. 1. represents the armature built up of segments of iron, with insulating
material between. The armature shown is to replace the gramme type, but it is
equally applicable to other forms.
Fig. 2. shows the armature complete mounted on the spindle ready for driving, on
one of the plans described.
a is the ring of insulating material.
b is the brass ring fitting into it.

page_text: Having therefore now particularly described and ascertained the nature of my said
Invention, I declare that what I claim is
1. An armature built up of segments of iron or other metal, substantially as
described.
2. The arrangement of the electrical connections between the segments substantially
as described.
3. The use of a special form of segment to preclude the formation of useless
currents, substantially as described.