Improvements in or connected with Drum Armatures for Dynamo, Electric Generators and Motors."
Year: 1897

page_text: Date of Application, 1st Nov., 1897-Accepted, 18th Dec., 1897
COMPLETE SPECIFICATION.
66 Improvements in or connected with Drum Armatures for Dynamo,
Electric Generators and Motors."
I, VALERE ALFRED FYNN; of 13 Bexley Road, Erith, in the County of Kent,
Electrician, 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:
The object of my invention is to so wind the drum armatures of dynamo
electric generators or motors working with direct or alternating currents of
electricity that the several spools, parts, or sections, forming the armature are
all of practically the same length and resistance, that they are symmetrically
situated, easily accessible, and readily inspected, and present as large a cooling
surface as possible and moreover so that the space occupied by the windings
shall be as limited as possible, the depth being so small that the cooling effect
is as uniform as possible, the number of soldered joints being entirely independent
of the number of conductors in each spool, part, or section, such joints being
reduced to the smallest possible number (there being such joints at the commu-
tator sections only) the several spcols, parts, or sections, being individually
insulated as completely as desired after they have been applied to the armature
without the necessity for previously bending or forming "such spools, parts,
or sections, to the requisite shape.
The winding according to this invention is more particularly adapted for
use in connection with slotted armatures and therefore. I will describe my
invention with reference to such armatures. Most of the qualities I have herein-
before enumerated belong to the known winding in which there are cylindrica!
end connections and is used where the output of a slotted armature is such that
two conductors only are required in each slot, these conductors being placed
separately one above the other in the slots the top layer being bent at each end
in one direction and the bottom layer being bent at each end in the opposite
direction. The conductors are each, after leaving the slot, carried round the
armature to the extent of usually one half the pitch. At the rear end a conductor
in the bottom layer is joined to a conductor in the top layer usually half way
through the pitch at a point where the two conductors are immediately above
each other, a ferrule being generally soldered over both. At the front end two
such conductors are soldered together to a commutator unright, also preferably
half way through the pitch.
Thus, besides the unavoidable soldered joints at the commutator uprights,
there is a corresponding number of solder joints at the rear end.
The conductors used in such cases are generally heavy and of such an oblong
section that it would be impossible to bend them in the required direction. In
some few cases where small conductors have been used they have been bent
over in the required manner thus reducing the number of soldered joints but
uch bending has usually been effected on special formers and the formed spools
or loops applied to the armature.

page_text: It will be evident to those conversant with the construction of dynamos that
the cases where such a winding can be employed are but limited.
Speaking generally such a winding is possible for different voltages with
very large machines, for low voltages only with medium machines, and for no
practical voltages at all for small machines.
" So as
5
The next possibility in that direction is the use of four superposed conductors
in each slot; this case has been dealt with in the following manner.
Conductors have been bent to the necessary shape in special "formers
to form one turn or loop. When one half of the loops had been put in place
each slot contained two conductors only and the other half of the loops had 1
to be put on before the holes were entirely filled.
The joints at the back were avoided but they were doubled at the commutator
end.
In other cases this winding has been carried out in the same manner as the
one first described every two superposed layers of conductors being alternately 1
soldered together at opposite sides and the free ends taken to the commutator
making the number of solder joints twice as great as in the case of two wires
in each slot.
I believe that it has never been attempted to arrange six superposed conductors
in each slot in regular winding with cylindrical end connections. In referring
here to the number of conductors or wires per slot I mean not the actual number
but the number of such conductors or wires which are in series with each other.
Should for instance three conductors be used in parallel in place of one con
ductor of larger section I treat them as one conductor only.
If in such case the winding be said to have two conductors per slot the actual
number of wires or conductors would not be two but six per slot.
The mode of winding according to my present invention makes it easy not
only to wind an armature without "forming" the conductors for cases where
there are four, six eight, or more superposed conductors in each slot, but also
enables that description of winding to be readily effected when the conductors
in each slot are placed not only above each other but two or more beside each
other, and when winding in this manner all joints but those at the commutator
can be avoided.
It will seldom be possible to arrange more than six conductors in a slot by
merely superposing them on account of the great depth of the slot then required
and therefore it is necessary to place the wires side by side. This case of a
plurality of conductors in each slot so that several are arranged beside each
other in several layers is almost the rule for small and medium sized dynamon
with slotted armatures.
The mode of winding adopted in such cases has invariably been either the
well known arrangement of conductors across the end faces of the armature and
near and around the shaft, an arrangement originally due I believe to von
Haefner-Alteneck (upon which innumerable attempts of improvement have been
made with only partial success) or the spool winding of Eickmayer and others.
The latter though possessing some of the qualities I enumerated at the outset,
diminishes the cooling surface of the armature itself, and involves an amount
of labour and consequent cost quite out of proportion to the size of the machine
as the spools have to be first wound on formers, and then forced into position
There is always a tendency to use as few slots as possible with such a winding, and
generally the fewer slots the worse the machine other things being equal. Ther
again the spools have to be carefully taped to be kept together and a good dea
of space is wasted unnecessarily in the case of low tension machines.
The former winding and its drawbacks are well known. It has all the dis
advantages which the winding according to my invention is intended to avoid.
In order to explain the mode of winding according to my invention I take a
an example a slotted four pole armature having seventeen slots, each slo

page_text: ntaining twelve conductors three side by side in our layers as
igure 1.
Let us further assume that a series connected drum is required the step then
ill be 1 to (7)+1=1 to (4+1).
Let the slots be numbered 1 to 17 as shewn in Figure 2. It is then necessary
wind from slot 1 into slot (1+4) the "step" of this winding is 1 to 5 or 0 to 4;
he spools are wound and connected to this same step. Let it be assumed that
here are seventeen commutator sections and seventeen spools with six turns each.
A general rule to be observed throughout is that consecutive conductors of
ne turn in each spool should always be similarly placed in their respective
lots but must be in different and adjacent planes.
In order that this first rule may be observed the number of layers must be
ven and the number of conductors per layer equal throughout or at least equal
n each pair of superposed and adjacent layers.
If this last condition be not fulfilled the first cannot be fulfilled and the
resulting winding is slightly irregular but it can still be carried out on the sare
general lines as the completely regular winding such as I now describe.
Another rule is that all conductors in the same layer should always be bent
in the same direction. As the conditions for a regular winding are very easy
of, fulfilment one would naturally always try to secure them. It is possible
with due regard to the two first rules to begin the winding in two different ways.
Winding from slot 1 into slot the first conductor may be placed in the first
layer into slot 1 so as to be nearest slot 17 then the first conductor in slot 5
will lay nearest slot 4 and be in the second layer.
After the conductor leaves slot 1 it is bent over in the direction of slot 5 the
angle being determined by the thickness of the conductors, their number si le
by side per slot, and the distance of the slots from each other.
Half way between slot 1 and 5 the wire which is still in the first layer is beut
the insulation of the wire. After the conductor has been taken through slot 5
that layer much at the same angle as it left slot 1. The change from one layer
to the other at a (see Figure 7) or b is done in an easy curve so as not to damage
After the conductor has been taken through slot 5
the insulation of the wire.
it is (still remaining in the second layer) bent towards slot 1 and about half
way between the two at bit is taken down into the first layer in the same way
as at it was taken from the first layer up to the second layer.
It will now be readily seen that the effect of placing the conductors in similar
resulting winding is slightly irregular but it can still be carried out on the same
distance from the end faces of the armature.
Having begun to wind the spool as described it becomes necessary in order to
get the second turn in place to thread the new or second conductor coming out
of slot under that portion of the first conductor already placed which proceeds
from into slot 5. After threading this second conductor can be bent up and
This proceeding clearly
back over itself at a and can be taken into slot 5.
entails much labour and would become very difficult with thick wire
5 Figure 7. It is therefore preferable to proceed differently.
see
The first conductor in slot 1 layer 1 should be placed so as to be nearest
slot 2; then the first conductor in slot 5 will be nearest slot 6 and in the second
layer (see Figure 6). The second conductor in slot will now
come outside
the first conductor and, after having been brought out to a, will be bent over
50 a portion of the first conductor from slot 1 to a, and come into the second layer
and run into slot 5 on the inside of the first conductor in slot 5. Reaching bit
will be bent down from the second into the first layer, will run through slot 1
on the outside of the second wire, at a will go onto the second layer and complete
the third turn through slot 5, on the inside of the second wire or conductor.
55 The appearance of the spool now is shown diagrammatically in Figure 6, the
thickest line representing the first turn, the thinnest the last turn. According
to the rules herein before mentioned conductors in slot 5 should be placed in

page_text: the second layer, those in slot 1 being in the first layer but in slot 5 there is as
yet no first layer. A dummy first layer should be inserted in the form of a
fibre strip (for very thin conductors this strip may be left out). The easy bends
at a and b are also preferably made over fibre sheets of suitable thickness and
shape.
In the case of a four pole machine these dummies are only necessary until
one quarter of the two layers being wound have been completed. After that
the wires already in place take the places and serve the purpose of the fibrous
pieces referred to. It will be apparent that it will be best for the second
spool to be wound through slots 17 and 4, and not through slots 2 and 6 the third
spool through 16 and 3, the fourth through 15 and 2 the fifth through 14 and 1.
The fifth spool can do without dummies as the first layer in slot 1 is already in
place. When about three quarters of the armature has been wound with the
first and second layers thirteen half spools have been put on (that is spools of
three turns only instead of six). In winding the fourteenth half spool which
goes into slots 5 and 9, the first layer is placed into slot 5 and the second layer
into slot 9. The first layer in slot 9 being already in place no difficulty is found
in placing the second layer. In slot 5 however where layer 1 is yet to be placed
layer 2 is already there. That second layer must therefore be lifted for the
time being out of the slot and the dummy (if such were used) removed and the
first layer be put in place. The same operation will have to be performed for
the slots 4, 3, 2 and it is convenient to raise these sides of the half spools out
simultaneously. The first two layers are now completed as soon as the still
missing first layers under the spools already wound have been put in and the
portions of the spools lifted out have been replaced.
The third and fourth layers are put on in exactly the same manner (and 'f
there were more than four layers there would be no difference). All the con-
ductors still available for completing the second half of the spools are hanging
at regular intervals away from the armature on the commutator side. Instead
of bending these wires at 6 down into the first layer as before I first bend them
up into the third layer, at a I bend them up again into the fourth layer, and
again coming to b down into the third layer and so on until they at last
emerge on the fourth or top layer having completed six turns per spool on
each of the 17 spools.
It will be noted that there are now seventeen ends emerging from this top
layer and bent in a different direction from the seventeen beginnings emerging
from the bottom layer these ends and beginnings will be connected two and two
to the commutator sections. For a four pole machine with a series drum in
order to carry out the "step" it is necessary to connect almost diametrically
opposite conductors as shewn in Figure 2.
These connections can be carried out in the form of commutator windings or
in the form of cylindrical end connections.
Figure shews the wires to be connected when a parallel drum is required it
will be seen that these additional connections are much shorter in this case.
In fact the wires to be joined almost naturally come above each other.
This difference does not exist in the known windings with cylindrical end
connections for the reason which will be obvious by inspecting Figure S
and Figure 9 which shew diagrammatically how the conductors lay for series and
parallel drums in the ordinary cylindrical end winding.
Figures 2 and 3 shew in a similar way this new cylindrical end winding.
For a four pole machine the connections for series and parallel drums span
about 90° in both cases in the known cylindrical winding Figures 8 and 9.
In the new cylindrical winding Figures 2 and 3 these connections span
about 270° for series drums, and about 90° for parallel drums.
4
5
All portions of the winding are situated between two cylinder surfaces the 5
one passing through the bottom of all slots the other through the top.
I have mentioned series drums and parallel drums as these are the principal

page_text: lescriptions of windings. The invention is applicable to the numerous variations
of the one or the other or of combinations of both.
The principle of the winding having been laid down there is no difficulty
n adapting it to any of the known modes of winding.
Figure 1 shews the position in the slot of the twelve conductors of the
particular winding described.
Figure 2 shews diagrammatically in two different manners the mode of
winding and connecting a series drum; the case of only four conductors in each
slot two side by side in two layers being selected for clearness of illustration,
only the first spool and the one this first spool is to be connected to being
shewn.
Figure 3 shews for the same conditions the mode of winding and connecting
of a parallel drum.
In both the last named figures the small circles represent the conductors in
the slots. The outside connections represent the connections at the back end
and the inside, those at the commutator end. The dotted lines shew conductors
in the first layer the full lines those in the second layer.
Figure 4 shews diagrammatically in two different ways a series drum con-
nection when four conductors in each slot are only superposed.
Figure 5 shews in the same manner a parallel drum connection for the same
conditions.
In these two last named figures there are of course four layers and they are
alternately distinguished by dotted lines and full lines.
To each of the principal diagrams Figures 2 to 5 is attached another diagram
illustrating in perhaps a simpler but not as accurate a manner a developement
of the connections.
When the wires per slot are only superposed then as in the case of two
wires only per slot the connections for series and parallel drums span 90° only
for four pole machines.
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
ciaim is:-
1. In a drum winding of any known description for a slotted armature the
slots or holes of which contain 4, 6 or more superposed wires the mode of
winding and connecting herein before particularly described by means of which
solder joints are avoided except at the commutator and the conductors are
wound on to the armature without previous "forming" those portions of the
conductors which are situated outside the slots or holes being symmetrically
situated and contained between two cylindrical surfaces one of these passing
through the bottom of all the slots and the other through the top.
2. In a drum winding of any known description for a slotted armature the
slots or holes of which contain any number of wires side by side per layer and
any number of such layers the mode of winding and connecting hereinbefore
particularly described by means of which solder joints are avoided except at the
commutator and the conductors are wound on to the armature without previous
forming" those portions of the conductors which are situated outside the slots
or holes being symmetrically situated and contained between two cylindrical
surfaces one of these passing through the bottom of all the slots and the other
through the top.
66
JOHNSONS & WILLCOX
47 Lincolns Inn Fields, London, W.C., Agents.