IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES AND ELECTRO-MOTORS.
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by the said Sir Charles Tilston Bright
at the Office of the Commissioners of Patents on the 4th May 1883.
Sir CHARLES TILSTON BRIGHT of 20 Bolton Gardens South Kensington, Knight
IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES AND ELECTRO-MOTORS.
In the machines hitherto constructed the coils either of the armature or field
magnets, or both, are made to rotate at a very high rate of speed.
In my invention the coils both of the armature and field magnets are fixed.
I wind the coils of the field magnets upon fixed hollow cores through which
passes an iron or steel shaft which is divided by a non-magnetic metal between
the coils; and the divided ends of the shaft, also made of iron or steel, are extended
into the form of segments of a circle or radial arms but on opposite sides to one
another, and so shaped that the outer ends of the segments or radial arms revolve
in the same plane.
The other ends of the shaft pass through an iron frame, in immediate proximity
to it but without actual contact with it's metal, the journals being supported upon
brass or gun metal plummer blocks.
In immediate proximity to the outer parts of the segments or radial arms a
circular series of insulated conducting coils are fixed, forming an armature which
may be either of the ring type, or may consist of a number of electro-magnets.
The outer surfaces of the segments or radial arms are shaped to correspond with
those of the armature.
This arrangement may be varied by using one field magnet through which the
iron or steel shaft passes with the projecting iron or steel segments or radial arms.
In another part of my improvements I employ as an armature, suitable to my
herein before described machine, a soft iron ring on the interior of which are fixed
radially a number of rectangular electromagnetic coils; These are in section
similar to a double headed iron girder, and the upper and lower parts serve as

page_text: flanges between which the insulated wire is wound. The inner poles are close
together, forming a circle, inside or about which the moving poles of the stationary
field coils revolve. This improved method of constructing armatures is also
applicable to other dynamo-electric machines and electro-motors, in which case the
poles of the field magnets are placed opposite to the outer ring.
Another part of my improvements relates to the commutators by which the
electrical connexions of the coils are changed. It is usual to employ bundles of
wires against which insulated plates connected to the ends of the coils make a
rubbing contact as the armature revolves, which method of making contact is
disadvantageous.
In my invention the ends of the armature coils are connected to divided
insulated metallic plates fixed to rings or cylinders, corresponding with and
adjacent to which are other insulated non-divided rings or cylinders which are
connected to the positive and negative poles of the machine
Against or between each pair of the divided and non-divided rings or cylinders
I employ a circular metallic brush which revolves on it's own axis and against the
rings or cylinders, making electrical contact between them.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Sir Charles Tilston Bright in the Great Seal Patent Office on the
2nd November 1883.
Sir CHARLES TILSTON BRIGHT of 20 Bolton Gardens, South Kensington, Knight
"IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES AND ELECTRO-MOTORS ">
In dynamo electric machines and electric motors as hitherto constructed the coils
either of the armature or field magnets, or both, are made to rotate at a very high
rate of speed.
Now according to my invention the coils both of the armature and field magnets
are fixed. A suitable arrangement for carrying out my improvements is as
follows:-I wind the coils of the field magnets upon fixed hollow cores through
which passes an iron or steel shaft which is divided by a non-magnetic metal
between the coils; and the divided ends of the shaft, also made of iron or steel,
are extended into the form of segments of a circle or radial arms but on opposite
sides to one another, and so shaped that the outer ends of the segments or radial
arms revolve in the same plane. The other ends of the shaft pass through an iron
frame, in immediate proximity to it but without actual contact with it's metal,
the journals being supported upon brass or gun metal plummer blocks.
In immediate proximity to the outer parts of the segments or radial arms a
circular series of insulated conducting coils are fixed, forming an armature which
may be either of the ring type, or may consist of a number of electromagnets.
The outer surfaces of the segments or radial arms are shaped to correspond with
those of the armature.
I sometimes employ as an armature, suitable to my herein before described
machine, a soft iron ring on the interior of which are fixed radially a number of
rectangular electro magnetic coils; these are in section similar to a double-headed
iron girder, and the upper and lower parts serve as flanges between which the
insulated wire is wound. The inner poles are close together, forming a circle,
inside or about which the moving poles of the stationary field coils revolve. This
improved method of constructing armatures is also applicable to other dynamo
electric machines and electromotors, in which case the poles of the field magnets
are placed opposite to the outer ring.
Another part of my improvements relates to the commutators by which the
electrical connexions of the coils are changed. It is usual to employ bundles of
wires against which insulated plates connected to the ends of the coils make a
rubbing contact as the armature revolves, which method of making contact is
disadvantageous. In my invention the ends of the armature coils are connected
to divided insulated metallic plates fixed to rings or cylinders, corresponding with
and adjacent to which are other insulated nondivided rings or cylinders which are
connected to the positive and negative poles of the machine. Against or between
each pair of the divided and nondivided rings or cylinders I employ a circular
metallic brush which revolves on it's own axis and against the rings or cylinders,
making electrical contact between them.
In Figure 1 which is a sectional elevation of a dynamo electric machine or
electro motor constructed according to my invention, a b c d e represent in section
the hereinbefore described shaft, of which ab and de are made of iron or steel,
and o of gunmetal or brass or other suitable non-magnetic metal. The ends of the
poles ab and d e are expanded into segments of ciroles at b and d. I find it
desirable to enlarge the shaft at points a and in the form of a disc as shown in
the drawing. The shaft is supported by non-magnetic bearings or plummer blocks

page_text: .
at ff, which are carried on a frame G G. The base of this frame may be made of
steel plates, as shown by the dotted lines at h. The frame also carries the two
fixed coils of insulated wire and ¹¹, also shown in section, which surround
part of each end of the shaft, and are so connected as to cause one end to be
polarised north and the other south. The shaft passes freely through the coils
and the frame, it's journals being borne by the nonmagnetic plummer-blocks f, fr
The shaft with it's extended segments is shown in the drawing as adapted to
what is technically known as a "Gramme ring" shown in section at k k. This
ring and it's coils are fixed to a nonmagnetic bearing or bearings ll, fixed to the
frame G G.
"
My improved commutator or collector. is shown in section at m m figure 1.. It
consists of an insulator p, in the form of a disc upon which are fixed three concen-
tric rings 1, 2, 3, the inner and outer of which rings 1, and 3, are respectively
connected to the positive and negative poles of the machine. The centre ring 2 is
divided into insulated sections corresponding to the junctions of the coils of the
fixed armature, the connecting wire being led outside of one of the large coils
surrounding the shaft over a shield or guide, or through a pipe as shown in Figure 2
at i. is an insulated continuation of the shaft, to which are attached two arms
carrying the circular metallic brushes o o, which are not themselves connected to
'anything except in so far as they make contact between the inner divided ring and
the two outer rings, as shown in the drawing.
:
1
1
3
Figure 2 shows an elevation of a modification of the machine on the same
principle, in which the frame, instead of being made of iron or a combination of
iron and steel as described by reference to figure 1, is composed of a frame work of
iron bolted together by two iron rods around which coils of insulated wire are
wound so as to polarise the rods and frame work upon a current being passed
through the coils. G G is the frame. 9 9 are the coils wound round one of the
rods, part of which is seen at his the pipe through which the wires are
conveyed to the commutator from the fixed armature coils at k. The armature k in
this figure is represented in detached view at Figure 3, in which the coils are
shown partly wound as at a, and partly with the iron cores unwound as at b.
The fan shaped poles of the two parts of the shaft are seen in end view at N S.
Figure 4 represents the pole pieces in sectional side view; one of the coils (a) is
shown wound with the insulated wire, the other (b) showing the iron core alone;
c is the non-magnetic division.
Figure 5 shows a segment of a fixed ring shaped armature, with divisions q,
between which the insulated coils of wire a are wound the cores being shewn
unwound at b, b,
1.03 0.
Figure 6 represents a side view in section of the armature and the extended
poles of the shaft as adapted to it. In this figure a a, shows the outer fixed
supporting ring of the armature with it's coils of insulated wire. b bare the two
sides of the shaft, and c the non-magnetic division.
', יד'
1191
'
Figure 7 represents in plan a form of my invention in which the polarisation of
the shaft a a is effected by means of the poles of the main fixed coils b b. In this
figure the non-magnetic division is shown in plan at d. The armature and pole,
pieces are of the form represented in figure 6.. d is the outer ring by which the
coils of insulated wire are supported. The surface of the disc within the induction
chamber e may be corrugated as shown, in order to extend the magnetic surface.
In place of using electro magnets to excite polarity, I find it advantageous to
employ in machines of a small type permanent steel magnets.
**
It will be observed that in all these examples of my invention the only moving
part is the shaft with it's iron or steel pole pieces and the circular brush or springs
*for making contact between the different parts of the commutator.
3
i
t
"
Having now described the nature of my said Invention and suitable' means of
carrying the same into effect, I would remark that I do, not' restrict myself to the
special forms of apparatus described for the purpose, as various modifications may

page_text: •
be devised with the same object; but what I claim and desire to be secured to me
by the herein in part recited Letters Patent are:
Firstly In dynamo-electric machines and electro motors the employment of
movable induced poles substantially as herein described.
Secondly The fixed armatures as described, or any equivalent thereof.
Thirdly The commutator herein described, or any mere modification thereof.
Fourthly. The construction and employment of dynamo electric machines and
electro motors arranged and operating substantially as herein before described and
represented in the accompanying drawing.
In Witness whereof I the said Sir Charles Tilston Bright, have hereto set my
hand and seal this thirty first day of October in the year of our Lord one thousand
eight hundred and eighty three
CHARLES T. DRIGHT (ES.)