Improvements in Windings for the Armatures of Direct Current Dynamo Electric Machines.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in Windings for the Armatures of Direct Current
Dynamo Electric Machines.
I, VALERE ALFRED FYNN, of 13, Bexley Road, Erith, in the County of Kent,
Electrician, do hereby declare the nature of this invention to be as follows:-
This invention has for its object to provide improved windings for the arma-
tures of direct current dynamo electric machines, (whether generators or motors).
It is especially adaptable to armatures of the so called slotted type. The slots may
have any convenient shape, and may be entirely open, or partially closed. The
windings may also be applied to armatures provided with tunnels, or holes, in
their laminations instead of slots. By my invention I arrange the windings in
the slots or holes, so that the self induction of the armature is greatly reduced
which will have the effect of reducing considerably the "lead" required to be
given to the brushes of a generator or the “lag" to be given to the brushes of a
motor when the load is varied from nothing to full load, or more, and consequently
reduce the tendency of the machine to spark at the brushes, or for the same lead
or lag it will have the effect of increasing the effect of any given machine.
According to my invention I distribute the active wires on each side of the same
spool of a given winding into two, or more, adjacent slots, or holes, instead of
bunching all the active wires on each side of the same spool into the same slot, or
hole, as hitherto.
The combinations of the different portions into which the spools have been
divided will of course vary with different cases but in all cases the wires thus
placed in different adjacent slots or holes, and belonging to the same spool, should
be connected in series. Connecting wires, not symmetrically placed with regard
to the poles, in parallel with each other, would entail a heavy loss due to internal
differential currents.
The self induction of a winding is the greater the easier it is for the magnetic
flux produced by that winding to close around that winding.
Thus it is well known that the self induction of an armature wound in holes
is far greater than that of an armature wound in slots, and the self induction of
this latter is considerably more than that of a smooth core armature..
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The wires belonging to the same side of the same spool should be so placed that
this path of the magnetic lines is rendered as long and as difficult as possible.
This reduces the self induction and by reducing the lead or "lag" reduces the
reaction of the field produced by the armature current on the field produced by
the exciting spools of the machine. It is well known that the smaller the angle the
brushes make with the neutral line at no load the smaller the "back ampere turns
of the armature.
"
This effect is obtained by splitting the coil in such manner that instead of being
wound in one slot or hole at each side it is wound through two, or more, adjacent
slots, or holes, on each side.

page_text: Thus the wires in two adjacent slots or holes (if each side of the spool be divided
into two holes or slots) belonging to the same spool will be traversed at any moment
by the same current flowing in the same direction, the field produced by each set
of wires will be exactly equal and of same direction, and therefore two equal and
opposed magnetising forces will act on the metal between such slots or holes, the
result of such action being that no flux at all will take place through the said metal
and the lines of the field produced by the two sets of wires will have to close
around the two slots or holes and 'will have therefore to traverse a very much
longer air space than if closing around one slot only. This new path is longer and
more difficult and I thus achieve my purpose.
Having described the conditions for the case where each spool of the winding is
split into two portions wound on each side through adjacent holes, or slots, it
will be readily understood how the same principle applies to cases when the spools
of the winding are split into more than two portions. The choice of the number
of portions into which the spools of a given winding had best be split will depend
on the size of the armature and on the nature of the work it may have to perform.
The principal advantage of this description of winding makes itself felt, of course,
at the moment when the coils pass, one after another, under the collecting brushes
and are short circuited by them.
The less self induction such a coil has the weaker reversing field will it require
to secure for it a sparkless commutation therefore the smaller "lead" or "lag"
will be required to be given to the brushes. Any of the different styles of winding
may be altered to fulfil the aforesaid conditions.
Dated this 1st day of June 1897.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.
Improvements in Windings for the Armatures of Direct Current
Dynamo Electric Machines.
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
This invention has for its object to provide improved windings for the arma-
tures of direct current dynamo electric machines, (whether generators or motors).
It is especially adaptable to armatures of the so-called slotted type. The slots may
have any convenient shape, and may be entirely open, or partly closed.
windings may also be applied to armatures provided with tunnels, or holes, in
their laminations, instead of slots. By my invention I arrange the windings in
the slots, or holes, so that the self induction of the armature is greatly reduced
which will have the effect of reducing considerably the "lead" required to be
given to the brushes of a generator or the " lag to be given to the brushes of a
motor when the load is varied from nothing to full load, or more, and consequently
reduce the tendency of the machine to spark at the brushes, or for the same lead
or lag it will have the effect of increasing the effect of any given machine.
"
According to my invention I distribute the active wires on each side of the same
spool of a given winding into two, or more, adjacent slots, or holes, instead of
bunching all the active wires on each side of the same spool into the same slot, or
hole, as hitherto.

page_text: The combinations' of 'the' different portions into which the spools have been
divided will of course vary with different cases but in all cases the wires. thus
placed in different adjacent slots or holes, and belonging to the same spool, should
be connected in series. Connecting wires, not symmetrically placed with regard
to the poles; in parallel with each other, would entail a heavy loss due to internal
differential currents.
The self induction of a winding is the greater the easier it is for the magnetic
flux produced by that winding to close around that winding.
Thus it is well known that the self induction of an armature wound in holes
is far greater than that of an armature wound in slots, and the self induction of
this latter is considerably more than that of a smooth core armature.
The wires belonging to the same side of the same spool should be so placed that
this path of the magnetic lines is rendered as long and as difficult as possible.
This reduces the self induction and by reducing the "lead" or "lag" reduces the
reaction of the field produced by the armature current on the field produced by
the exciting spools of the machine. It is well known that the smaller the angle the
brushes make with the neutral line the smaller the 6.
back ampere turns" of the
armature.
This effect is obtained by splitting the coil in such manner that instead of being
wound in one slot or hole at each side it is wound through two, or more, adjacent
slots, or holes, on each side.
Thus the wires in two adjacent slots or holes (if each side of the spool be divided
into two holes or slots) belonging to the same spool will be traversed at any moment
by the same current flowing in the same direction, the field produced by each set
of wires will be exactly equal and of same direction, and therefore two equal and
opposed magnetising forces will act on the metal between such slots or holes, the
result of such action being that no flux at all will take place through the said metal
and the lines of the field produced by the two sets of wires will have to close
around the two slots or holes and will have therefore to traverse a very much
longer air space than if closing around one slot only. This new path is longer and
more difficult and I thus achieve my purpose.
Having described the conditions for the case where each spool of the winding is
split into two portions wound on each side through adjacent holes, or slots, it
will be readily understood how the same principle applies to cases when the spools
of the winding are split into more than two portions. The choice of the number
of portions into which the spools of a given winding had best be split will depend
on the size of the armature and on the nature of the work it may have to perform.
The principal advantage of this description of winding makes itself felt, of course,
at the moment when the coils pass, one after another, under the collecting brushes
and are short circuited by them.
The less self induction such a coil has, the weaker reversing field will it require
to secure for it a sparkless commutation therefore the smaller "lead" or lag
will be required to be given to the brushes. Any of the different styles of winding
may be altered to fulfil the aforesaid conditions.
The accompanying drawing illustrates the method of splitting a spool, consisting
of three turns, into three adjacent slots, (holes, or tunnels), for a four pole drum
armature with sixty-seven slots and sixty-seven commutator segments, (indicated
at E), with six superposed wires per slot, (marked 1 to 67).
For clearness of illustration two spools only, A, B, and C, D, are shewn.
The spool A B, is wound from the slot 1, into the slot 18, then to and from the
slot 2 to the slot 19, and then to and from the slot 3 to the slot 20, and the spool CD
is shewn similarly wound, but winding into any other sequence of slots can be
adopted provided the three wires, at each side of the spool, are placed, as shewn,
in three adjacent slots, and that the sides of the spools lie at, or approximately at,
the distance of one armature "step" from each other. For instance the spool A. B
*.** ...

page_text: can be wound from slot 1, into slot 20, then into slot 2, and slot 19, and then into.
slot 3 and slot 18.
From the foregoing description and illustration the possible variations will be
apparent but the first described arrangement is preferred.
When applied to a slotted Gramine armature the conductors on the outer
periphery of the armature, or the active conductors where they are embedded into
slots, should be split into adjacent slots. Those on the inner periphery, or the idle
conductors, may be wound in the ordinary way as the inner periphery is generally
smooth. If, as sometimes happens, the inner periphery is also slotted it is advan-
tageous to split the conductors of the same spool into corresponding adjacent slots
on the inner periphery but this is not essential.
The mode of winding according to my invention is therefore applicable to either
drum or Gramme wound armatures.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
Windings, for slotted, or tunnelled, armatures of direct current dynamo electric
machines, wherein the active wires on each side of the same spool of the winding,
are distributed into two, or more, adjacent slots, tunnels, or holes, in the armature,
and connected in series; substantially as hereinbefore explained.
Dated this 28th day of February 1898.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.