IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
We WILLIAM HARDING SCOTT of 36 Park Street, Nottingham, Nottinghamshire
Electrician and EDUARD ALEXANDRE PARIS of 1 Warbeck Road, Shepherd's Bush
in the County of Middlesex, Electrician, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES," to be as follows
5 that is to say :-
This Invention relates to dynamo-electric machines of the kind described in the
Provisional Specification accompanying an Application for a Patent No 4683 of 1884
and it has for its object the improvement in the construction of armatures for
dynamo-electric machines.
According to this Invention the revolving drum-shaped armature has its ends
formed as described in the Specification herein before referred to but instead of
being wound with wire strips of copper are laid longitudinally from end to end of
the drum. The strips of copper are connected to strips placed at points on the
circumference of the drum nearly equal to but a little more or less than the
distance between the centres of the magnets used. Each end of the copper strips
are bent down over the end of the drum. The strips are connected together as
follows. Each bent down end of each copper strip is soldered to a turned up
part at one end of a thin curved flat copper plate. This flat plato is formed by
cutting a piece of thin sheet copper in a circular form but with a part at each end
of greater width than its middle part or as it were with a part of its outside edgo
cut away between the ends. This plate when there are four magnets is slightly
longer than the quadrant of the circle of the drum end and is curved to correspond
to the circle of the drum. At one end a small oblong piece is cut away on the side
nearest the axis of the drum and the oblong part at the end left is bent at right
angles and it is to this bit that the end of the longitudinally laid strip is soldered.
At the opposite end of the curved plate a small oblong piece is turned up from the
portion nearest the cut away part and to this bit is soldered the bent down end of
another copper strip Inid longitudinally along the drum at a part along its
circumference nearly at right angles to the strip fastened to the other end of the
curved plate. The copper strips are so connected that a strip 1 at one end of the
curved Hat plate is connected through it to another strip 2 laid longitudinally at a
part on the circumference of the drum distant from the strip 1 equal to the distance
between the centres of the magnets. This strip 2 is connected at the other end of
the drum by another curved flat plate to another strip 3 similarly placed at the

page_text: same distance to No 2 and No 3 is again connected but at the opposite end
of the drum to another strip 4 and so on until the surface of the drum is
covered. The copper strips and curved plates are all properly insulated from one
another.
With the foregoing arrangements a current will pass as it were along a strip (1) 1
then along the plate at one end of the drum along a strip (2) and thence along
another plate at the end of the drum to another strip (3) The number of times a
current will cross the outside of the drum before it has gone completely round the
drum will be equal to the number of magnets employed.
The connections to the commutator are taken of the plates at one end of tho
drum and are arranged as in the Invention described in the Provisional Specification
hereinbefore referred to so that by using four brushes only those strips that are in
the magnetic field at one time are in circuit.

page_text: COMPLETE SPECIFICATION.
We, WILLIAM HARDING SCOTT of 36 Park Street, Nottingham, Nottinghamshire,
Electrician and EDUARD ALEXANDRE PARIS of 1 Warbeck Road, Shepherd's Bush,
in the County of Middlesex Electrician, do hereby declare the nature of our said
Invention for "IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES," and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement that is to say:-
Our said Invention relates to dynamo-electric machines of the kind described in
the Specification of Letters Patent granted to us dated 11 March 1884 No 4683
and it has for its object the improvement in the construction of armatures for
dynamo-electric machines.
According to our said Invention the revolving drum shaped armature has its ends
formed as described in the Specification No 4688 of 1884 herein before referred, but
instead of being wound with wire, strips of copper are laid longitudinally from end
to end of the drum. These strips of copper are connected to strips placed at points
on the circumference of the drum nearly equal to, but a little more or less than the
distance between the centres of the magnets used.
And in order that our said Invention and the manner of performing the same
may be properly understood we proceed to describe the same with the aid of the
accompanying sheet of drawings hereunto appended. In these drawings the same
reference numerals or letters are used to mark the same or like parts wherever they
are repeated.
Figure 1 on the accompanying sheet of drawings is a view of one end of an
armaturo, figure 2 being a plan, and Figure 3 a view of the opposite end to
figure 1. All the three figures are drawn to correspond so as the better to explain
our improvements. The drum 4 forming the armature is laid longitudinally with
strips 5 of copper. Each end of these copper strips 5 is bent down over the end of
the drum 4 and the strips 5 are connected together as follows. Each bent down
end of each copper strip 5 is soldered to a turned up part at one end of a thin
curved flat copper plate 6. This plate 6 is formed by cutting a piece of thin sheet
copper in a circular form but with a part 7 at each end of greater width than its
middle part or as it were with a part of its outside edge cut away between the
ends. The form of this plate 6 will be best understood by referring to figure 4 on
the accompanying drawings. The plate 6 when there are four magnets is slightly
longer than a quarter of the circle of the drum end and is curved to correspond to
the circle of the drum. At one end a small oblong piece is cut away on the inner
or shorter side of the plate 6 leaving a short oblong part 8 at the outer or longer
side and this part 8 is bent at right angles to the plate 6. It is to this part 8 that
the end of the longitudinally laid strip 5 is soldered when placed on the drum 4.
At the opposite end of the plate 6 a small somewhat similar oblong piece 0 is
turned up from the part 7 at that end nearest the cut away part, and to this
piece 9 there is soldered the bent down end of another copper strip 5 which is laid
also longitudinally along the drum 4 at a part nearly at right angles to the strip 5
fastened to the other part 8 at the other end of the curved plate 6. The copper
strips 5 aro so connected that a strip 5 at A. at one end of the plate 6 is connected
through it to another strip 5 laid longitudinally at a part B on the circumference
of the drum 4, distant from the strip at A equal to the distance between the centres
of the magnets. The strip 5 at B is connected at the other end of the drum (see

page_text: figure 1) by another plate 6 to another strip 5 at C. This strip 5 is placed
similarly at a distanco apart equal to that between the strips at A and B and this
strip 5 at C is again connected but at the opposite end of the drum 4 to another
strip 5 at D and so on until the surfaco of the drum is covered. It is of course
necessary that the copper strips 5 and curved plates 6 be properly insulated from
one another. As the plates 6 at the ends of the drum 4 are added they will with
the insulating material between them slightly increase the length of the drum 4
and consequently the longitudinal strips require to be successively longer. The
bent down ends therefore will require to be bent down in a suitable mould or
matrix as the building up or covering of the armature progresses. It is necessary
that every alternate strip 5 be connected to the commutator and this is effected by
extending the end of that strip 5 nearest its commutator as shown at A figure 2,
and at this end in this case the bent down part is brazed or rivetted on. Figure 5
is a diagram representing the method of placing the longitudinal strips 5, the full
lines indicating the connections at one end of the armature and the dotted lines tho
corresponding connections at the opposite end. In forming the armature the space
left between the first strip 5 say at A and the strip 5 at B is gradually filled in by
the succeedingly laid strips, until the building up of the armature is completed
when it will be found that the space between A and B has been entirely filled up.
with the strips 5 and insulating material. When the wholo space is filled up the last
laid strip 5 must be connected by one of the plates 6 to the end of the first laid
strip 5 left free for that purpose. The total number of longitudinal strips required
to form the armature may be found by taking any multiple of the number of
magnet polos + or - 1 and multiplying that number by 2. For example let N be
the number of magnet poles thon the number of strips will be 2 (N + 1) or 2
(N-1) and the number of strips connected to the commutator will be-half that;
that is to say, N-1 or N + 1.
'The armature instead of being formed on a hollow drum round a fixed iron coro
may be formed on a core composed of iron discs or plates insulated from one
another and these discs may have teeth or projections on their peripheries. With
the foregoing arrangements a current will pass as it were along a strip 1 then along
the plates at one end of the armature, along a strip 2 and thence along another
plate at the opposite end of the armature to another strip 3- and so on.
The
number of times a current will cross the outside of the drum 4 before it has
gone completely round the armature will be equal to the number of magnets
employed.
The connections to the commutator are taken off the plates at one end of the
drum and are arranged as in the Specification of letters Patent hereinbefore
referred to, so that by using four brushes only those strips that are in the magnetic
field at one time are in circuit.
+
Having now particularly described and ascertained the nature of our said
Invention and in what manner the same is to be performed wo declare that what
wo claim is
(1) The improved method of forming an armature built up of copper strips (5)
and plates (6) substantially as and for the purposes herein before described with
reference to the accompanying drawings.
"
(2) The improved method of making connection across the ends of an armature
by plates (6) of sheet copper substantially as herein before described with referenco
to the accompanying drawings.